Strand, London, WC2A 2LL
B e f o r e :
| HALLIBURTON ENERGY SERVICES, INC.
|- and -
|(1) SMITH INTERNATIONAL (NORTH SEA) LIMITED
(2) SMITH INTERNATIONAL, INC.
(3) SMITH INTERNATIONAL ITALIA SpA
David Kitchin QC, Adrian Speck and James Abrahams (instructed by Bird & Bird) for the Defendants
Hearing dates: 19-21, 24-28, 31 January, 1-4 February 2005
Crown Copyright ©
Mr Justice Pumfrey : Introduction
62. For example, if a significant amount of breakage or chipping was consistently found in certain locations of the cutting structure of these dull bits, consideration would-be given to changing the number, shape or material used for the teeth in these locations. Adding rows of teeth to distribute the drilling forces may be considered. If this type of chipping or breakage was only found occasionally, the bit records for those bit runs. would be analyzed to determine if excessive WOB, excessive rotary speed or some other condition could have been the cause for the breakage. Consideration would also be given to the effects that changes to the tooth shape or quantity could have on the penetration rate of the bit. The experience and judgement of the bit designer would eventually be used to make changes to the design.
63. Another example would be if excessive wear was consistently noted in certain areas of the cutting structure, changes in the profile of the cone might be considered to decrease the amount of gouging and slicing that those teeth would experience. Again the effects that these changes would have on bit performance would be considered before changes would be made.
64. Unusual wear patterns observed on the bit would be considered in an attempt to determine possible causes for these conditions. Sharpening wear of the teeth on a bit can result from a condition known as "tracking". This condition is where as the cones rotate, one tooth falls into a crater on the bottom of the hole that has been caused by a previous tooth hitting at the same location. This condition causes a loss of penetration rate and results in wear to the cone shell as well as the teeth of the bit. Concentric rings worn into the cone shell can indicate that the bit is "running off-center" and is therefore not covering the bottom of the hole with cutting teeth in the desired locations as intended. This condition also results in decreased penetration rates and decreased bit life. Changes that would be considered to correct these conditions could include adding or removing. rows of teeth, changing the pitch scheme of teeth in the rows of teeth, changing the shape and length of teeth or other changes that a designers experience would indicate.'
The Force Balancing patent
' The present invention relates to down-hole drilling and especially to the optimisation of drill bit parameters. In particular it relates to a roller cone drill bit, a method of designing the same, and a rotary drilling system.'
'Chisel shaped inserts have opposing flats and a broad elongated crest resembling the teeth of a steel tooth bit. Chisel shaped inserts are used for drilling soft to medium formations The elongated crest of the chisel insert is normally oriented in alignment with the axis of cone rotation. Thus, unlike spherical and conical inserts the chisel insert may be directionally oriented about its center axis. (This is true of any tooth which is not axially symmetric.)The axial angle of orientation is measured from the plane intersecting the center of the cone and the center of the tooth.'
' It has long been desirable to predict the development of bottom hole patterns on the basis of the controllable geometric parameters used in drill bit design, and complex mathematical models can simulate bottom hole patterns to a limited extent. To accomplish this it is necessary to understand first, the relationship between the tooth and the rock, and second, the relationship between the design of the drill bit and the movement of the tooth in relation to the rock. It is also known that these mechanisms are interdependent.'
This passage acknowledges the existence of 'complex mathematical models' that simulate bottom hole patterns. The bottom hole pattern is the cutting pattern left by the teeth in the formation at the bottom of the hole as the bit, subject to the WOB, rotates. The passage points out that in order to simulate the bottom hole pattern two things must be known: the way in which the tooth interacts with the formation and second 'the relationship between the design of the drill bit and the movement of the tooth in relation to the rock'. The specification acknowledges that it is known that these mechanisms are interdependent, and it could not be otherwise, because the forces acting on a cone are made up of the forces transmitted by the leg of the bit and the drag caused by the passage of the teeth through the rock along a path constrained by the geometry of the bit as it rotates in the hole.
' To better understand these relationships. much work has been done to determine the amount of rock removed by a single tooth of a drill bit. As can be seen by the forgoing discussion, this is a complex problem. For many years it has been known that rock failure is complex, and results from the many stresses arising from the combined movements and actions of the tooth of a rock bit. (Sikarskie, et al, PENETRATION PROBLEMS IN ROCK MECHANICS, ASME Rock Mechanics Symposium. 1973). Subsequently. work was been done to develop quantitative relationships between bit design and tooth-formation interaction. This has been accomplished by calculating the vertical, radial and tangential movement of the teeth relative to the hole bottom to accurately represent the gouging and scraping action of the teeth on roller cone bits (Ma, A NEW WAY TO CHARACTERIZE THE GOUGING SCRAPING ACTION OF ROLLER CONE BITS Society of Petroleum Engineers No 19448, 1989) More recently computer programs have been developed which predict and simulate the bottom hole patterns developed by roller cone bits by combining the complex movement of the teeth with a model of formation failure (Ma THE COMPUTER SIMULATION OF THE INTERACTION BETWEEN THE ROLLER BIT AND ROCK Society of Petroleum Engineers No 29922, 1995). Such formation failure models include a ductile model for removing the formation occupied by the tooth during its movement across the bottom of the hole and a fragile breakage model to represent the surrounding breakage.
 Currently roller cone bit designs remain the result of generations of modifications made to original designs. The modifications are based on years of experience in evaluating bit run records and dull bit conditions. Since drill bits are run under harsh conditions, far from view, and to destruction it is often very difficult to determine the cause of the failure of a bit. Roller cone bits are often disassembled in manufacturers' laboratories, but most often this process is in response to a customer's complaint regarding the product, when a verification of the materials is required. Engineers will visit the lab and attempt to perform a forensic analysis of the remains of a rock bit but with few exceptions there is generally little evidence to support their conclusions as to which component failed first and why. Since rock bits are run on different drilling rigs in different formations under different operating conditions it is extremely difficult [to] draw conclusion[s] from the dull conditions of the bits. As a result, evaluating dull bit conditions, their cause and determining design solutions is a very subjective process. What is known is that when the cutting structure or bearing system of a drill bit fails prematurely it can have a serious detrimental effect of the economics of drilling.'
Force balanced Roller-Cone bits
'the roller cone bit designs should have substantially equal mechanical downforce on each of the cones. This is not trivial: without special design consideration, the weight on bit will NOT automatically be equalised among the cones.'
The Addressee of the specification
The Rock Bit Computer Model
'3 Q. Does it not therefore follow that the bit designer would be
4 aiming to design his bit, at least one of his objectives in
5 designing his bit, would be to ensure that the loads acting on
6 these bearings, as between the cones, were the same or as
7 close to the same as he could manage?
8 A. Again, running the risk with, and all due respect, loads
9 per se in the act of bit design really are not considered
10 implicitly. They are by moving [compacts] around, by deciding
11 how many cutting teeth to put on a cone, whatever. He would
12 know that he is effecting the way in which the cone would be
13 loaded, but loads per se had not been a part of bit design.
14 They are just not known, so they were not really considered.
15 Wear was the element that actually drove design modifications.'
'After having the single element force model the next step is to determine the interaction between inserts and the formation drilled. This step involves the determination of the tooth kinematics (local) from the bit and cone kinematics (global) as described bellow
(1) The bit kinematics is described by bit rotation speed O=RPM (revolutions per minute), and the rate of penetration, ROP. Both RPM and ROP may be considered as constant or as function with time.
(2) The cone kinematics is described by cone rotational speed. Each cone may have its own speed. The initial value is calculated from the bit geometric parameters or just estimated from experiment. In the calculation the cone speed may be changed based on the torque acting on the cone.
(3) At the initial time, t0, the hole bottom is considered as a plane and is meshed into small grids The tooth is also meshed into grids (single elements). At any time t, the position of a tooth in space is fully determined. If the tooth is in interaction with the hole bottom, the hole bottom is updated and the cutting depth for each cutting element is calculated and the forces acting on the elements are obtained.
(4) The element forces are integrated into tooth forces, the tooth forces are integrated into cone forces, the cone forces are transferred into bearing forces and the bearing forces are integrated into bit forces.
(5) After the bit is fully drilled into the rock, these forces are recorded at each time step. A period time, usually at least 10 seconds, is simulated. The average forces may be considered as static forces and are used for evaluation of the balance condition of the cutting structure.'
' There is a distinction between force balancing techniques and energy balancing. A force balanced bit uses multiple objective optimization technology, which considers weight on bit, axial force and cone moment as separate optimization objectives. Energy balancing uses only single objective optimization as defined in equation (11) below.'
(a) Selection of design variables. In the simplified example given by reference to Figure 3, these are tooth-related, the cone profile, offset and journal angle being assumed to be invariant. The design variables are the radial position of the tooth, the length of the crest and the tooth angles.
(b) Definition of objectives, and expression of objectives as function of design variables. In the example given, the objective selected is to let each cone remove the same amount of rock in one revolution of the bit. It appears to be assumed that the bit has a specified cutting depth per revolution (it is called ., and is never referred to again in the specification). It is then stated that
'It is not difficult to calculate the volume removed by each row, and the volume matrix may have the form
This expression is vacuous: it states that there exists a matrix V which describes the amount of rock removed per row of teeth (the index j) and per cone (the index i). So far as the patent is concerned, all the Vij are to be calculated as functions of the design variables. There is no disclosure in this document of a method (an algorithm, an analytic expression or whatever) for doing this. The matrix V is not the end of the matter, because it is recognised that the matrix calculated in a 2-D manner, which I assume means on the assumption of a cone rolling about a radius with no offset, must be further modified by a scale matrix, the elements of which reflect the number of teeth and the tracking condition. I quote paragraph :
'In reality the removed volume by each row depends not only on the above design variables, but also on the number of teeth on that row and the tracking condition. Therefore the volume matrix calculated in a 2D manner must be scaled. The scale matrix, KV may be obtained as follows.
where V3d0 is the volume matrix of the initial designed bit (before optimization). V2d0 is obtained from the rock bit computer program by simulate the bit drilling procedure at least 10 seconds [sic]. V2d0 is the volume matrix associated with the initial designed matrix and obtained using the 2D manner based on the bottom pattern shown in Figure 4. The volume matrix has the final form
In fact, equations (9) and (10) are the same. Equation (10) repeats the information that the matrix is a function of the four variables identified in paragraph , that is the selected design variables. Paragraph  told us that the elements Vij of the matrix V are functions of the design variables. The actual objective is identified finally in paragraph , which is to minimise the root mean square deviation in volume removal between the cones.
(c) Define the bounds of the design variables and the constraints. This stage is described in paragraphs -. Examples are given (minimum tooth crest length, for example) and it is emphasised that it is particularly important to avoid interference between teeth on different cones during rotation, and to specify the width of the uncut rings on the hole bottom. Further expressions are given which merely repeat what is said in words (equations (12) and (13)). These are purely geometrical constraints.
(d) Solution of the problem. Paragraph  describes how to carry out the optimization of the design.
' After having the objective function, the bounds and the constraints. the problem is simplified to a general nonlinear optimization problem with bounds and nonlinear constraints which can be solved by different methods. Figure 6 shows the flowchart of the optimization procedure. The procedure begins by reading the bit geometry and other operational parameters. The forces on the teeth, cones: bearings, and bit are then calculated. Once the forces are known, they are compared, and if they are balanced, then the design is optimized. If the forces are not balanced, then the optimization must occur. Objectives, constraints. design variables and their bounds (maximum and minimum allowed values) are defined, and the variables are altered to conform to the new objectives. Once the new objectives are met. the new geometric parameters are used to re-design the bit, and the forces are again calculated and checked for balance. This process is repeated until the desired force balance is achieved.'
It is worth observing that the whole of the description of the preferred embodiment, this passage apart, is concerned with volume balancing, as paragraph  makes clear. That paragraph explicitly states that once volumes are equalized, force balancing is also achieved. This is inconsistent with paragraph  and slightly inconsistent with paragraph , where it said to happen 'in most cases'. I do not think this particularly matters.
The relevance of the Orientation patent to the Force-balancing patent
'US Patent Application 09/387,304 filed 31 August 1999' if he wants any information about how to implement a bit design system according to this invention. I quote the passage: 'U.S. Patent Application 09/387.304, filed 31 August 1999 (issued as US patent 6.095,262), entitled "Roller-Cone Bits, Systems, Drilling Methods, and Design Methods with Optimization of Tooth Orientation" (Atty. Docket No. SC-98- 26), and claiming priority from U.S. Provisional Application 60/098.442 filed 31 August 1998, describes roller cone drill bit design methods and optimizations which can be used separately from or in synergistic combination with the methods disclosed in the present application.'
Let me take an example. If the designer is interested in force-balanced bits with conical inserts, whose cutting effect does not depend upon orientation, why, one might ask, should he look at this specification at all? There is no direction to consult the specification with a view to obtaining further information on the modelling techniques called for by the claim. I do not think it is legitimate as a matter of interpretation to take a passage such as that above and build out of it a suggestion that if the skilled person is at a loss as to how to proceed, the solution to his problem is, or may be, available in the cited publication. For this reason, the disclosure of the Orientation patent is not part of the disclosure of this patent, and I can interpret the claims without regard to it.
'4.18 Reference documents
References in European patent applications to other documents may relate either to the background art or to part of the disclosure of the invention.
Where the reference document relates to the background art, it may be in the application as originally filed or introduced at a later date (see II, 4.3 and 4.4).
Where the reference document relates directly to the disclosure of the invention (e.g. details of one of the components of a claimed apparatus), then the examiner should first consider whether knowing what is in the reference document is in fact essential for carrying out the invention as meant by Art. 83:
If not essential, the usual expression "which is hereby incorporated by reference", or any expression of the same kind, should be deleted from the description.
If matter in the document referred to is essential to satisfy the requirements of Art. 83, the examiner should require the deletion of the above-mentioned expression and that, instead, the matter is expressly incorporated into the description, because the patent specification should, regarding the essential features of the invention, be self-contained, i.e. capable of being understood without reference to any other document. One should also bear in mind that reference documents are not part of the text to be translated pursuant to Art. 65.'
The claims of the Force Balancing patent
A method of designing a roller cone drill bit comprising a plurality of arms rotatable cutting structures mounted on respective ones of said arms and a plurality of teeth on each of said cutting structures, the method comprising the steps of
(a) calculating the volume of formation cut by each tooth on each cutting structure (16) of the roller cone drill bit (10);
(b) calculating the volume of formation cut by each cutting structure per revolution of the drill bit;
(c) comparing the volume of formation cut by each of said cutting structures with the volume of formation cut by all others of said cutting structures of the bit;
(d) adjusting at least one geometric parameter on the design of at least one of the culling structures; and
(e) repeating steps (a) through (d) until substantially the same volume of formation is cut by each of said cutting structures of said bit (10) when the drill bit is drilling into a formation.
A method of designing a roller cone drill bit comprising a plurality of arms, rotatable cutting structures mounted on respective ones of said arms and a plurality of teeth on each of said cutting structures, the method comprising the steps of:
(a) calculating the axial force acting on each tooth (18) on each cutting structure (16) of the roller cone drill bit;
(b) calculating the axial force acting on each cutting structure per revolution of the drill bit;
(c) comparing the axial force acting on each of said cutting structures with the axial force on the other ones of said cutting structures of the bit;
(d) adjusting at least one geometric parameter on the design of at least one of said cutting structures; and
(e) repeating steps (a) through (d) until substantially the same axial force will act on each cutting structure when the drill bit (10) is drilling into a formation.
Construction—when a drill bit is drilling into a formation
Construction: 'axial force'
'(a) The first, overarching principle, is that contained in Art 69 itself. Sometimes I wonder whether people spend more time on the gloss to Art 69, the Protocol, than to the Article itself, even though it is the Article which is the main governing provision.
(b) Art 69 says that the extent of protection is determined by the terms of the claims. It goes on to say that the description and drawings shall be used to interpret the claims. In short the claims are to be construed in context.
(c) It follows that the claims are to be construed purposively – the inventor's purpose being ascertained from the description and drawings.
(d) It further follows that the claims must not be construed as if they stood alone – the drawings and description only being used to resolve any ambiguity. The Protocol expressly eschews such a method of construction but to my mind that would be so without the Protocol. Purpose is vital to the construction of claims.
(e) When ascertaining the inventor's purpose, it must be remembered that he may have several purposes depending on the level of generality of his invention. Typically, for instance, an inventor may have one, generally more than one, specific embodiment as well as a generalised concept. But there is no presumption that the patentee necessarily intended the widest possible meaning consistent with his purpose be given to the words that he used: purpose and meaning are different.
(f) Thus purpose is not the be-all and end-all. One is still at the end of the day concerned with the meaning of the language used. Hence the other extreme of the Protocol – a mere guideline – is also ruled out by Art 69 itself. It is the terms of the claims which delineate the patentee's territory.
(g) It follows that if the patentee has included what is obviously a deliberate limitation in his claims, it must have a meaning. One cannot disregard obviously intentional elements. Hoffmann LJ put it this way in STEP v Empson  RPC at 522:
"The well known principle that patent claims are given a purposive construction does not mean that an integer can be treated as struck out if it does not appear to make any difference to the inventive concept. It may have some other purpose buried in the prior art and even if this is not discernible, the patentee may have had some reason of his own for introducing it."
(h) It also follows that where a patentee has used a word or phrase which, acontextually, might have a particular meaning (narrow or wide) it does not necessarily have that meaning in context. A good example of this is the Catnic case itself – "vertical" in context did not mean "geometrically vertical", it meant "vertical enough to do the job" (of supporting the upper horizontal plate). The so-called "Protocol questions" (those formulated by Hoffmann J in Improver v Remington  FSR 181 at p.189) are of particular value when considering the difference of meaning between a word or phrase out of context and that word or phrase in context. At that point the first two Protocol questions come into play. But once one focuses on the word in context, the Protocol question approach does not resolve the ultimate question – what does the word or phrase actually mean, when construed purposively? That can only be done on the language used, read in context.
(i) It further follows that there is no general "doctrine of equivalents." Any student of patent law knows that various legal systems allow for such a concept, but that none of them can agree what it is or should be. Here is not the place to set forth the myriad versions of such a doctrine. For my part I do not think that Art. 69 itself allows for such a concept – it says the extent of protection shall be determined by the terms of the claims. And so far as I can understand, the French and German versions mean the same thing. Nor can I see how the Protocol can create any such doctrine.
(j) On the other hand purposive construction can lead to the conclusion that a technically trivial or minor difference between an element of a claim and the corresponding element of the alleged infringement nonetheless falls within the meaning of the element when read purposively. This is not because there is a doctrine of equivalents: it is because that is the fair way to read the claim in context.
(k) Finally purposive construction leads one to eschew what Lord Diplock in Catnic called (at p.243):
"the kind of meticulous verbal analysis which lawyers are too often tempted by their training to indulge."
Pedantry and patents are incompatible. In Catnic the rejected "meticulous verbal analysis" was the argument that because the word "horizontal" was qualified by "substantially" whereas "vertical" was not, the latter must mean "geometrically vertical."'
(a) Given that the words 'cutting structure' undoubtedly mean 'cone', the literal meaning of the words 'calculating the axial force acting on each tooth on each cutting structure' at first sight indicates the axis of the tooth, principally because when the tooth is not in formation there is no force on it. Generally speaking, a force acting on the tooth will have a component along the tooth's major axis: this is what is shown as the WOBi in figure 2.
(b) The skilled reader would realise that the forces acting on the tooth varied very substantially as the cone rotated. The specification does not say anything about the loads on the journal bearings (that is, perpendicular to the cone axis) as one of the forces to be equalized. The journals carry a substantial proportion of the WOB, as a quick look at Figure 2 makes clear. To this extent, equalisation of WOB per cone will tend to make the journal loadings more equal.
(c) The words 'axial force acting on each cutting structure per revolution of the drill bit' may be thought to suggest a different axis but the phrase 'force per revolution' read literally is more or less meaningless because the force will not increase with the number of revolutions. If one remembers that the force on individual teeth will vary greatly as they enter, interact with, and leave the uncut formation on the hole bottom as the cone rotates, it seems sensible to suppose that what the claim is probably looking at is the average axial force over a rotation of the bit, i.e. over somewhat more than one rotation of a cone.
(d) Feature (c) of the claim seems to me to throw no light on the question which axis is being talked about. To equalise forces acting along the axis of the cones makes sense, since it will tend to equalise wear on the cone thrust bearings. It is also one of the forces expressly referred to in paragraph  and . To equalise WOB per cone also makes sense. Feature (c) is accordingly indifferent as to the nature of the axial force under discussion, and the same goes for (d) and (e).
(e) Claim 6 does provide some oblique support for the construction for which Halliburton contend. It calls for a bit in which in use 'the axial force on each of said cutting structure[s] is between [31%] and [35%] of the total of the axial force on the bit…'. It is only possible to construe claim 6 so as to be consistent with the meaning of claim 3 for which Smith contends if the word 'force' relates to the magnitudes of the axial components of the forces on the cones, ignoring their direction, since they are more or less at right angles to the bit axis. There is every reason to make the cone-axis components of the cone forces equal in magnitude (this is what equation (5) describes) because that will ensure that the forces acting perpendicularly to the bit axis sum approximately to zero. Nobody suggested a plausible reason for relating them to WOB at all. This claim plainly relates to the bit-axis component of the force on each cone.
Construction: the product claims
'6. A roller cone drill bit comprising:
- three arms;
- one rotatable cutting structure mounted on each one of said arms; and
- a plurality of teeth on each of said cutting structures;
wherein the number and locations of said teeth are not identical between ones of said rotatable cutting structures;
characterised in that the axial force on each of said cutting structure is between thirty-one percent and thirty-five percent of the total of the axial force on the bit when the drill bit is drilling into a formation.
7. A roller cone drill bit comprising:
- three arms;
- one rotatable cutting structure mounted on each one of said arms; and
- a plurality of teeth on each of said cutting structures, wherein the number and locations of said teeth are not identical between ones of said rotatable cutting structures;
characterised in that the volume of formation drilled by each of said cutting structures is between thirty-one percent and thirty-five percent of the total volume drilled by the drill bit when the drill bit is drilling into a formation.'
Infringement of the Force Balancing patent—general
1. Incorporation of the cutting structure CAD file into a larger overall CAD file including bearings and legs;
2. Production of engineering specifications, bills of materials, manufacturing drawings, tooling lists, CNC programs;
3. Manufacture of the legs, a complex process in itself;
4. Manufacture of cones with milled teeth including the steps of forging, rough boring, external machining, shot-blasting, case-hardening, grinding and turning— the complexity of milling a cone with integral teeth can be seen immediately from the figure on for example page 10 of Halliburton's inspection report, which is a Pro/E display showing what the result should look like;
5. For cones with machined inserts, the like complexity, with the addition of drilling the holes and pressing them in;
6. Finally, cleaning, greasing and assembly of the legs, followed by insertion of ball bearings and the plugging of the hole, and welding together of the legs.
The IDEAS software in use
'14. As 1 have explained, my objective in producing this design was to create a bit that could compete effectively with an existing Hughes product. I identified that the Hughes product had a weakness in the gage row [the outermost row on each cone]. In order to design around this weakness I identified the following (in decreasing order of importance) as optimization criteria for my design:
• Gage Forces;
• Gage Scraping Distance;
• ROP; • Fz Inserts; and
• Cone Balance.
15. I set out my optimization criteria in a Power Point presentation which I gave at the design review meeting which the design team normally holds to discuss new designs. A copy of that Power Point presentation is attached marked Exhibit "AS-6". The first of my criteria was to optimize the forces acting on the gage row of each of the cones of the bit. It can be seen from the charts on page 13 of the Power Point presentation that compared to the 15 MFD and the GFi18 bits, the forces acting on the gage rows on my new design were much lower. The second criterion was to optimize the scraping distance that was covered by each of the gage rows on my design. Page 14 of the Power Point presentation demonstrates that I was able to even up the distance (and therefore the amount of work) that each of the 3 gage rows covered in my new design. My third criterion was ROP. As page 15 of the Power Point Presentation clearly shows, my new design had a much faster ROP in the Leuders Limestone than the comparator bit. It also performed marginally faster in the Carthage Marble than either the 15MFD or the GFi18. My fourth criterion was to optimize the Fz force on each of the inserts of my bit. I was attempting to create a design where the highest force acting on any one tooth at any one time was lower than any of the baseline or comparator bits that I had investigated, in order to avoid insert breakage, particularly on the drive rows of the bit. The drive rows are essentially the 'middle' rows on the cone in between, but not including, the gage row and the nose row. Finally, my fifth optimization criterion was to balance the cones on the bit that I designed. By this I mean that, to the extent possible without detracting from what I had achieved for the other more important criteria, I was attempting to balance the Fz forces acting on the cones of this bit. However, this was only one of my optimization criteria. In fact it was the least important of the five criteria that I identified and, as with all the design work on bits, the final design was a compromise, trying so far as possible to achieve my various goals. As a result it is difficult to quantify how well I achieved my goals and, in particular, this last one.
16. Unfortunately I cannot remember which cutting structure I used as my starting model in Pro/E when I created this design. However, I think that I probably used the cutting structure design for the GFi18 as my start point, and then made alterations to that in order to create my new design. As far as I recall, the changes that I made to my starting design were made in Pro/E. I do not remember whether I used 1ayout.tk at all.'
3 Q. We have seen that one of your optimization criteria was to
4 balance the Fz forces as indicated in the product and process
5 description. When you were designing the 174GXI, that was one
6 of your criterion.
7 A. Yes. Obviously, as everyone understands by now, balancing the
8 forces on the cones is not going to hurt anything. To an
9 extent, yes, that has been one of my criterias when
10 I designed. It is not always the most important criteria. On
11 a mill tooth bit, my Lord, typically you are drilling a soft
12 formation; so the key there is how fast you can drill. They
13 do not drill for too long, there is not too much wear on the
14 bit, so all the other factors that you are looking at cannot
15 sacrifice the ROP. You are trying to compromise between ROP,
16 the forces on the cones, forces on the teeth, and so on, but
17 the predominant factor on a mill tooth bit is ROP because you
18 want to drill fast.
19 In the end, you have to land up feeling happy about
20 a compromise that you made, that, OK, the forces on my cones
21 are 38%, 29%, close enough, but my ROP is 20 % faster. Now
22 I would not drop my ROP or sacrifice it to be 15% faster in
23 order to get my forces to be 33, 33, 33. That would not make
24 any sense for that specific bit. Yes, I would look at the
25 forces on the cones, but that would not - not at the expense 2 of ROP, or some of the other factors that I was looking at.
8 Q. There are a number of internal Smith documents stressing that
9 force balancing, that is the Fz force one was talking about,
10 has an optimization criteria. Would you agree that it was
11 known amongst the Smith designers that when designing
12 a criteria, an important criteria was to attempt to force
13 balance the Fzs?
14 A. Again, I guess you have to go back to the deposition. It
15 depends on the application of the rock that you are drilling.
16 Also you are talking about a prior art pre-IDEAS design or
17 IDEAS design?
18 Q. I am talking about IDEAS designs.
19 A. Yes, it just depends. For softer rock, maybe it is not a good
Infringement of the Force balancing patent—the particular bits
(a) 122 GFi18SD: Amardeep Singh: the Singh/18 bit.
(b) 160 GXiV/160MGXi: Scott McDonough: MM8355, MM4541 and MM3439: the McDonough bit.
(c) 174 GXiV: Amardeep Singh: Singh/twist bit.
(d) 084 FGSi30ODV: Dennis Cisneros/Joshua Gatell: the Cisneros bit.
(e) 122 GFi11YV: Amardeep Singh: the Singh/11 bit.
(f) 160 MGS05V: Gary Portwood: the Portwood bit.
'12 Q. All right. It was just .... You were also, while using IDEAS,
13 attempting to balance the Fz force on the cones as one of the
15 A. Yes.
16 Q. Your bit, as I understand it, and we have the details, you ran
17 it with different parameters, the final design, what you
18 believed to be the final design. For some parameters, it was
19 better balanced than others. Is that right?
20 A. Yes. '
17 Q. And you are showing the sales force that as a result of using
18 IDEAS, you were able to arrive with your new (the red) bit at
19 a design which was much more closely balanced in terms of the
20 total cone Fz force.
21 A. Correct.
22 Q. Presumably if this graph was what you were showing the sales
23 force, this is data taken from the final design.
24 A. Yes. I believe this was one of the sets of data from my final
25 designs. I believe this was run at different parameters, but 1209
2 everything else remaining the same - the model and also the
3 rock file, the chisel rock file that I had used.
4 Q. And you were telling the sales force, so they could tell the
5 customer, that here you are, you had achieved the level of
6 balance we see on page 5.
7 A. Correct.
...a) The Patent provides no or no sufficient teaching of a method of design.
(b) The Patent provides no or no sufficient disclosure of how to calculate the volume of formation cut by each tooth or by each cutting structure; what comparison is made in relation to the volumes of formation cut or how that comparison is calculated; how to utilise the results of the comparison for the purposes of the iteration referred to; or how to account for the physical aspects of drilling into a formation, in particular how to determine and apply the physical properties of the formation and/or the bit.
...c) The Patent provides no or no sufficient teaching of a method of design.
(d) The Patent provides no or no sufficient disclosure of how to calculate the axial force acting on each tooth and on each cutting structure; what comparison is made in relation to the axial forces or how that comparison is calculated; how to utilise the results of the comparison for the purposes of the iteration referred to; or how to account for the physical aspects of drilling into a formation, in particular how to determine and apply the physical properties of the formation and/or the bit.
...e) The Patent provides no or no sufficient disclosure of or how to achieve a roller cone drill bit which is characterised in that the axial force on each of said cutting structures is between thirty-one and thirty-five percent of the total of the axial force on the bit when the bit is drilling into a formation, or of the formation referred to.
...f) The Patent provides no or no sufficient disclosure of or how to achieve a roller cone drill bit which is characterised in that the volume of formation drilled by each of said cutting Structures is between thirty-one and thirty-five percent of the total volume drilled by the bit when the bit is drilling into a formation, or of the formation referred to.
5. If, which is denied, the Claimants' products and/or process infringe the claims of the Patent (or any of them) then the specification of the Patent does not disclose the invention claimed clearly enough and/or completely enough for it to be performed by a person skilled in the art in that the scope of protection of those claims is so wide that the claims extend beyond the patentee's contribution to the art (if any).'
'The subsection is concerned with the disclosure of the invention in the specification. Thus it is necessary to read the specification through the eyes of the skilled addressee to ascertain what is the invention that is disclosed. Even where patents relate to articles, the inventions disclosed in difference specifications can be different in kind. For example, the invention disclosed may relate to an article which will perform a particular function or an article which is cheaper to make that similar articles. In the latter case, it is the very essence of the invention disclosed in the specification that the article can be made more cheaply and therefore too perform the invention the person skilled in the art must be able to make the article cheaply as described in the specification. In the former case, the person skilled in the art must be able to produce the article which will perform the function, as that is the invention disclosed.
The section requires the skilled man to be able to perform the invention, but does not lay down the limits as to the time and energy that the skilled man must spend seeking to perform the invention before it is insufficient. Clearly there must be a limit. The subsection, by using the words "clearly enough and completely enough," contemplates that patent specifications need not set out every detail necessary for performance, but can leave the skilled man to use his skill to perform the invention. In so doing he must seek success. He should not be required to carry out any prolonged research, enquiry or experiment. He may need to carry out the ordinary methods of trial and error, which involve no inventive step and generally are necessary in applying the particular discovery to produce a practical result. In each case, it is a question of fact, depending on the nature of the invention, whether the steps needed to perform the invention are ordinary steps of trial and error which a skilled man would realise would be necessary and normal to produce a practical result.
The section requires the skilled man to be able to perform the invention. Such a man is the ordinary addressee of the patent. He must be assumed to be possessed of the common general knowledge in the art and the necessary skill and expertise to apply that knowledge. He is the man of average skill and intelligence, but is not expected to be able to exercise any invention. In some arts he may have a degree, in others he will be a man with practical experience only. Further, in circumstances where the art encompasses more than one technology, the notional skilled person will be possessed of those technologies which may mean that he will have the knowledge of more than one person.'
(a) The skilled reader would be unable to set up the geometrical model of the bit, and in particular the transformations required for the kinematic calculations are inadequately disclosed, the volume matrix V3d0 being difficult to work out and not described;
(b) The skilled reader would be unable to calculate the forces acting on the teeth, and in particular paragraph  of the specification is misleading and wrong in assuming that force and volume may be equated (equations (1) to (3)) and no method of calculating forces for the purpose of paragraph  is described. The experiments, equipment and data required are not described.
(c) The skilled reader would be unable to calculate the cone-bit speed ratio, and in particular paragraph (2) is obscure and may require a calculation nowhere described which is both complex and difficult; and
(d) The section of the specification entitled 'Design of a Force Balanced Roller Cone Bit' contains such inaccuracies and omissions as would prevent the skilled reader from designing a bit by following the instructions provided.
15 MR. BURKILL: I was going to since that one was just a for
16 instance. Let us move on to drill bits specifically. Leaving
17 aside your rate of penetration concern, which we will
18 obviously come to, the computer modeller would be able to
19 model a roller cone drill bit if provided sufficient geometry
20 to show the position of teeth, cones and bit relative to each
21 other and those could be combined into an assembly and
22 displayed on a computer screen, could they not?
23 A. I do not agree that it is an easy problem. If I explain how
24 I see it, perhaps that will help. The problem is one of
25 3-dimensional geometry as far as I think your question is. As
2 a concept, it is clear what is happening. One can easily
3 visualize this thing descending and the cones rotating and the
4 teeth moving and saying that I could put a spot of white paint
5 on one tooth in one position, then as the thing moves I could
6 take, for example, photographically a series of pictures and
7 I would be able to see where that point had moved in the
8 operation of the drill bit. But it has to be said that the
9 geometry is complicated. Whether you use matrix methods or
10 whether you use Euler angles -- in another reference you show
11 me Euler angles, or Bryant angles or Euler parameters, or the
12 3-dimensional trigonometry that Ma use, whatever you use, the
13 result must be the same because that point has one and only
14 one trajectory, given the starting parameters. So whether
15 this calculation is done by matrices and transforms or whether
16 it is done by 3D geometry in the way that Ma did it, the
17 upshot must be the same. Otherwise either Ma is wrong or
18 whoever has done it is wrong. There is not any doubt about
19 it. It is 3D geometry. It has an answer right or wrong . If
20 the correct answer is arrived at, my position is just this,
21 that it does not make it any easier to do it by matrix
22 transforms than to do it by the method that Professor Ma
23 adopted. In the end you have to come to the equations that
24 are in Ma's book which tell you where that little spot of
25 white paint is at every instant of time. Although we can
2 discuss matrix transformations, and of course they are in the
3 engineering undergraduate curriculum, that is completely
4 different from saying here is a complicated 3-dimensional
5 geometrical problem, what is it solution?
8 A. My position is that CAD was commonplace in the industry. It
9 could model the shape of very complex mechanical engineering
10 components like a roller drill bit, so that it would produce
11 effectively a photograph of the device in three dimensions and
12 could you look at it from above, from below, the side and at
13 an angle. All that could certainly be done, but what it could
14 not do is model either the kinematics or the dynamics of how
15 the drill bit works.
16 Q. In the ground. Works in the ground is ----
17 A. The kinematics is not in the ground. The kinematics is
18 a theoretical exercise with the drill bit, if you like, in
19 suspended animation -- not cutting. That is what Ma deals
20 with in his chapter 2 and reaches the equations in chapter 2
21 that I am talking about - his kinematic equations. Then
22 another issue is the whole one of tooth to formation
13 Q. But, on the other hand, you might reward him for using
14 a little initiative in appreciating that these things are all
15 out there already, would you not?
16 A. Well, in describing the project as I have, I would certainly
17 expect the student to study the literature and to see Ma's
18 book and the papers that led to that book and possibly the SPE
19 paper, although there are difficulties mentioning that in this
20 context, but to look at the literature. Even if I took the
21 equations straight out of Ma's book, it would still be
22 a significant project because you have got to understand all
23 the aspects of them and get the correct numbers into them and
24 model this. Following all those points on every tooth, into
25 contact with the ground and out of contact with the ground, is
2 just a huge task. I know how students get things wrong and
3 projects do not work out, even though they may seem to be
4 conceptually very simple. The devil is in the detail of this
5 project, in my opinion.
6 Q. But all this could be done with techniques known in the art
7 well before 1998.
8 A. They would be using conventional techniques for 3-dimensional
9 computer modelling.
10 Q. So you would not disagree when Smith, in their own patent, say
11 that this is something that could be done using techniques
12 known in the art?
13 A. I would not disagree that it uses techniques known in the art.
14 It is just that they are complex and getting it right is
15 a difficult thing to achieve.
10 Q. To get a sufficiently accurate determination of the cone to
11 bit speed ratio, to make one's model worthwhile, one would
12 need to consider the forces acting on the teeth.
13 A. I feel that that would be desirable, yes. It is not
14 essential, but it is desirable to get accurate results, yes.
15 Q. If we consider together a cone to bit speed ratio, it may be
16 anything between 1 and 1.5, may it not?
17 A. Typically they would be included in that range. 1 would be an
18 abnormal one, but 1.2-1.5 I would feel to be a more reasonable
19 potential range.
20 Q. 1.2-1.5. If, for example, one has an error of, say, 1% to the
21 cone to bit speed ratio, that translates into 3.6 degrees
22 every rotation of the bit, does it not?
23 A. It would.
24 Q. And over 10 seconds, a period of simulation considered by this
25 patent, there may be 40 revolutions of the bit, may there not? 517
2 A. There may be.
3 Q. So even with a 1% error, the estimate of cone position may
4 bear no relationship to reality. Is that fair?
5 A. That is the potential problem that exists with any simulation.
6 There is the error that can result. I will accept your
7 numbers. Yes, I would agree.
8 Q. Accordingly, to determine the forces acting on the cone with
9 any reasonable degree of accuracy, may I suggest to you that
10 it is therefore necessary to actually calculate the cone to
11 bit speed ratio by taking into account the forces acting on
12 the teeth as they interact with the formation?
13 A. I would agree that that should give you the most accurate
14 results. In fact, a varying cone to bit speed ratio would
15 enhance the accuracy of the results.
16 Q. And, indeed, that is what you need to get a worthwhile model.
17 A. The term "worthwhile" would be a controversial term. You can
18 get a simulation without total accuracy. The better the
19 accuracy, the more reasonable the simulation. Professor Ma
20 thought that he was doing meaningful stuff, and I do not
21 believe that he had an accurate determination. My point is
22 that the more accurate the result, the input, the more
23 accurate the output. That is true of any simulation.
'The element forces are integrated into tooth forces, the tooth forces are integrated into cone forces, the cone forces are transferred into bearing forces and the bearing forces are integrated into bit forces.'
'5 A. It does not. I construe figures 1, 2 and 3 as not being your
6 modelling at all. This is the data acquisition guidance where
7 you will feed information into your model. This I do not
8 believe by any means as being the patentee's method of telling
9 you how to model. This is telling you how to determine data
10 that will be used when you do your modelling. This is just
11 describing indentation tests by which your interaction between
12 teeth and formation properties will be determined. I cannot
13 conceive of anybody believing that this would be guidance as
14 to your actual simulation. This is just guidance as to
15 determining the properties of the formation and the nature of
16 the forces that will exist when a tooth interacts with that
17 formation both in an axial and a lateral fashion.
18 Q. May I respectfully suggest that that is simply not consistent
19 with the description at paragraph 40, which is discussing the
20 use of an element force model, and it is saying that the force
21 on an element in the normal direction may be determined by the
22 application of equation 1.
23 A. I still disagree. If you will read the first sentence, "The
24 present invention uses a single element force-cutting
25 relationship in order to develop the total force-cutting
2 relationship of a cone [with the bit]". But the effort here
3 is coming up with the force-cutting relationship. It is not
4 actually performing the simulation yet. It is rather
5 determining the nature of the forces that will result from
6 either axial or lateral motion of a tooth when engaged in
7 a given formation. That is why the specific formation
8 properties are being determined here by these equations.
9 Again, my understanding is unquestionable, that it has nothing
10 to do with the simulation itself per se. It is only providing
11 me with the cutting relationship between axial and lateral
12 motions that will be ascertained during my simulation. By
13 these equations I can calculate the forces when I know what
14 the axial and lateral motions are at a given point in time of
'16 Q. Yes. You break it down into vertical matchsticks. As far as
17 those concerned, if they are in contact with the rock, then
18 you use those to calculate the forces from equations 1, 2 and
19 3, do you not?
20 A. Well, as I understand what this model does, and beginning
21 initially with equation 1, it takes a matchstick of elemental
22 size Sc. It does not give any information as to what
23 that area is. It says it is a cross-section on the XY plane.
24 I understand that. It does not tell you how big it is,
25 whether large, small or infinitesimal. It does not appear to
2 come into the resulting calculation, nor does the length LE,
3 along the Z axis. This force formulation seems to say that
4 the vertical force is in proportion to the depth of
5 penetration SE to the rock parameter s, which
6 is defined as the compressive strength of the rock, and
7 a parameter ke associated with the formation
9 I think it must be true, must it not, that on any
10 analysis ke must depend on the area Sc and will not be
11 a property of the rock per se but the property would be
12 something to do with the size of the matchstick. At any rate,
13 the formulation says that the vertical upforce on the
14 matchstick is in proportion to its depth of penetration and
15 that you can assemble a bundle of matchsticks into a complete
16 tooth and you will then have an accurate model or
17 a satisfactory model of the upthrust on the tooth. I have not
18 seen any evidence that that is a correct realistic
6 A. Possibly I did not make my answer clear. I will attempt
7 again. The simulation will give me a geometric interaction of
8 teeth with formation. I can determine from that interaction
9 an axial penetration of the tooth. This equation will give me
10 the force in an axial direction that results from that.
1 I will know from my simulation the direction of motion
12 sideways of that tooth and equations 2 and 3 give me my method
13 of assigning a force value to that motion.
14 Q. I am sorry, Mr. Hall, I think I am failing to make myself
15 clear. The forces actually bearing on a tooth, as it goes
16 through the formation, may well be, and indeed are likely to
17 be, very different to the forces necessary to produce your
18 threshold mu that you have described is the practical result
19 of carrying out the tests of two and three. That must be
20 right, must it not?
21 A. I would disagree. You would recall my example of a plough and
22 the land. Once motion occurs, regardless of how far or
23 theoretically how fast you would do that, that force will
24 remain the same. Work will increase, as you go further, but
25 the force will remain the same.
2 Q. There is no explanation here as to how to take into account or
3 determine the forces acting on a tooth which is moving at an
4 angle to the surface of the formation other than axially or
6 A. It is an angle of motion not composed of axial and sideways
8 Q. I suggest to you, Mr. Hall, that a skilled person would
9 appreciate that the forces acting on the tooth, as it is
10 moving axially or scraping through the formation, cannot be
11 resolved by a simple application of what you have described,
12 the result of experiments 1, 2 and 3 to be.
13 A. I would submit that in my opinion, sir, it can. If I am
14 moving at an angle into formation, I am, by so doing,
15 increasing my depth of penetration and moving sideways.
16 I have equations to give me both of the forces that result
17 from those components of motion. That is what these tell me.
18 That is what they teach me.
19 Q. They only give you the threshold, do they not, as you have
20 described your mule analogy? What equation 2 on your analysis
21 gives you is the force which would be necessary to get that
22 element moving, and that is all.
23 A. That is correct, because once it begins to move, it can move
24 indefinitely at that force level.
25 Q. May I ask you a slightly different question. To determine any
2 forces, one would have to test a tooth. Is that correct?
3 A. You would have to conduct at least one test on some tooth,
4 that is correct.
5 Q. One would then have to try and work backwards and determine
6 the forces acting on each element which you have chosen to
8 A. To utilize this preferred embodiment of breaking it into
9 elements, that would be correct. This is only a preferred
10 embodiment and, therefore, if you so chose, you could conduct
11 multiple tests on actual teeth and actual formation and just
12 use your element as one relative to that tooth; but, yes, you
13 would have to work backwards to use this preferred embodiment
14 elemental model. That is correct.
15 Q. All one can derive from that is information for an average
16 element in a tested tooth. Is that not so?
17 A. I disagree, again, an "average" element. I do not understand
18 your term there, but you would break your tooth up
19 analytically where you fix the number of elements, the
20 location of the elements, the sideways exposure of the
21 elements, and it would be up to the modeller to determine the
22 exact nature of the elemental analysis that he was performing.
'The cone kinematics is described by cone rotational speed. Each cone may have its own speed The initial value is calculated from the bit geometric parameters or just estimated from experiment. In the calculation the cone speed may be changed based on the torque acting on the cone. '
'Q Could Professor Ma accurately calculate the forces on a cone per revolution of the drill bit. A No he could not.
Q Why not, sir? A He's never come up with a method of determining the true cones speed ratio to bit speed ration to be able too do that. Even though that sounds like a simple thing, it really is very important in really determining the true forces that act on a bit.
So the force and the penetration rate and all that sort of thing all depend on being able to accurately determine really what speed this cone is going to turn relative to the speed of the bit. And it's a very complex thing to do, because like I say, it's constantly changing. And it depends on the combination of inputs of all these teeth.
Q Now sir, is it also complicated because some of the teeth don't just actually cut through the ground, but they actually slide or skip along the ground? A. No question about it, that's correct, yes.
Q Could Professor Ma accurately calculate the cone speed too bit speed ratio? A No, he could not, and he stated that he could not on several of his publications.'
'12 Q. And the patent gives you no help along that road.
13 A. It is mute along that line. I was trying, I do not know if
14 you desire it, but like I say, Hughes actually undertook to
15 attempt to develop such a program. We did work on it for
16 several years and finally abandoned it because it never
17 accurately forecast what the bit would do. That was one of
18 the reasons why we never could come up with an accurate cone
19 speed to bit speed ratio. Our indentations were not in the
20 right location, and all that sort of thing.
Conclusions on insufficiency
20 Q. And he would be aiming to ensure that the wear did not occur
21 unevenly between those bearings.
22 A. That would be one aspect that he would consider.
23 Q. And, consequently, he would be aiming, would he not, to try
24 and ensure that the loads, for example, on the thrust
25 bearings, if we take those to start with, the loads on the
2 thrust bearings, were the same as between each of the cones.
3 A. With all respect, I would have to state he would not actually
4 even think about loads per se but, rather, he would observe
5 wear and his intent would indeed be to try and even wear; but
6 loads per se, not having any method of determining,
7 calculating, those, all he really observes is wear.
8 Q. But he would understand that wear is caused by load?
9 A. That he would understand, yes.
16 Q. And he would appreciate that if there was an imbalance in the
17 wear on the thrust bearings, for example, that would be as
18 a result of an imbalance in the load on the thrust bearings.
19 A. He would have that intuitive knowledge, yes.
20 Q. Similarly, if he saw an imbalance in the wear on the journal
21 bearings, he would appreciate that that was because there was
22 an imbalance in the load of the journal bearings.
23 A. Possibly. There are other reasons for wear.
The design of the various bit parts is largely dictated by the formation properties and size of hole. The three legs and journals are identical, but the shape and the distribution of cutters on the three cones differ. The design should also ensure that the three legs are equally loaded, to avoid the excessive loading of one leg only. The following factors are normally considered when designing and manufacturing of soft and hard three-cone bits: (a) journal angle; (b) amount of offset; (c) teeth; (d) bearings; and (e) interrelationship between (c) and (d).
Important bit nomenclature is presented in Figures 4.3 and 4.4.
The bit journal is the bearing load-carrying surface, as shown in Figures 4.5 and 4.6. The journal angle is defined as the angle formed by a line perpendicular to the axis of the journal and the axis of the bit. Figure 4.6 is a section through one leg of a three-cone bit. Angle θ in Figure 4.6 is the journal angle.
The magnitude of the journal angle directly affects the size of the cone. An increase in journal angle will result in a decrease in the basic angle of the cone and, in turn, cone size. Figure 4.7 shows how the cone size decreases as the journal angle increases from 0º to 45º. At a journal angle of 45° the cutters can theoretically become truly rolling.
The smaller the journal angle the greater the gouging and scraping action by the three cones….
10 Q. There is no dissection of the various forces and discussion as
11 to downforce as a pure force on its own?
12 A. That is true and therefore when I read that, I would say it
13 means that if we take the phrase "the three legs are equally
14 loaded" and that means that all the loads are essentially the
15 same as taken between cones, it is not restrictive into
16 bearings. It is not restrictive into forces on legs. It is
17 not restrictive as regards the direction of any of the forces
18 which may be on the bearings or the legs or the cones or
19 anything. It is a general statement that to the extent that
20 it is possible, my Lord, things should be balanced up.
(transcript 1096) who took the view that it confused two questions, viz. would the designer consider that load imbalance caused wear, and what could he do about it, given that load could not be measured. He regarded the proposition that it was necessary to balance the downforce (WOB) between the cones as being (variously) so evident that it did not need to be mentioned and blindingly obvious (transcript 1122), providing the forces could be measured.
The Ma Paper.
'In this paper, the surface of each tooth of roller bits is represented by scores of points, whose 3-D compound coordinates are used to reflect the shape and size of the tooth. Thus the cutting structure of the bit together with their movement is represented by the time-sequence of the coordinates of the several thousand points. Hence, the computer simulates the roller bit.'
Ma's teaching is not straightforward, and the language gives difficulty from time to time, but what he provides is a scheme for simulating the action of the bit on the rock, and so the penetration of the bit into the rock. He describes the deficiencies of existing models in this way:
'Up to, now, however, all the bit's motion models, the interacting force models, the ROP and torque models of roller bits are obtained by simplifying the interaction between the bit and bottom hole. The major simplifications and suppositions are: (1) without any regard to the shape and size of the tooth by using a point or a line of the tooth; (2)'. Mistaking the compound motion of the tooth as vertical motion and . . regarding the force as proportional to the inserted depth; (3) Neglecting the bumps and craters and taking the bottom hole as a plane or smooth cones; (4) Regardless of the shape and size of craters and modelling only by a relation model. of the crater volume with the inserted depth; (5) Neglecting the differences among the contacting teeth and thinking that each has the same interacting force with the bottom hole and breaks the same volume of rock.
Although these models revised by fitting the field data or the experiment data and have some values of applications after being, yet their scopes of application are very limited. In particular, they can not reflect the effect of subtle changes of bit structures such as the shape and size of the tooth, the cone offset, the shape of cones and the arrangement of teeth on cones, on the bit motion, the interacting force and the ROP.'
'(1)The position of the bit cutting structure and the relative position of the teeth in space.
(2)The shape and size of the bottom hole and the well bore.
(3)The interacting factors such as the contacting teeth of the bit, the number of the contacting teeth, the inserted depth of each tooth, the shape and size of the inserted part of each tooth.
(4 )The size and direction of each interacting force.
(5)The shape and size of a crater by any contacting tooth.
(6)The torque of the bit and the size and direction of the resultant lateral force.
(7)The deviation and the lateral displacement of the bit.'
'Compared with the conventional methods (design, manufacture, test and repeating the circle), to develop a new type of roller bit, this software can save a lot of expenses and time.'
'In view of bearing loads it would therefore be desirable to have a bit with the same button pattern on all rollers. Each roller would then absorb the same amount of the feed force and all three rollers would be subjected to the same bearing toad But the demand for the largest possible rollers can be better met by provision of different button patterns. '
'In redesigns and new designs of roller bits it has proved necessary already on the drawing board to get some idea of the force balance on the bit, both that among the three rollers and that between individual bearings in anyone roller. This is done in a miniature computer of type PDP 11 by means of two simulation programmes specially prepared for roller bits. The FORTRAN programming language is used for this purpose. There is naturally an effort to achieve as good an agreement as possible between the simulation models and the bearing force measurements on the rig. The most difficult thing with the models is to describe as correctly as possible the play of forces between the cemented carbide button and the rock, how great the force is, in which direction it works, etc.
In order to get an idea of the magnitude of the bearing forces and their variation during rotation of the rollers, the bearing forces were previously projected on the drawing board geometrically for each 15º which the roller was turned. This was a time-consuming method and it took several weeks to draw one's way through the three rollers on a bit.
The corresponding work can now be performed in a few minutes with the aid of a computer. Today, it takes five minutes to calculate interval moves of 5º on the three rollers of a 250mm bit,. In this way a large number of alternative solutions can be calculated in order to arrive at the alternative which best satisfies the stipulated requirements.'
Soviet patent 1691497 'Tricone drill bit'
The Composite Catalog and the Reed lecture
'NOT AN INVENTION'
'4.—(1) Subject to subsection (2) below, an invention shall be taken to be capable of industrial application if it can be made or used in any kind of industry, including agriculture.
(2) an invention of a method of treatment of the human or animal body by surgery or therapy or of diagnosis practised on the human or animal body shall not be taken to be capable of industrial application.
(3) Subsection (2) above shall not prevent a product consisting of a substance or composition being treated as capable of industrial application merely because it is invented for use in any such method.'
'(a) a discovery, scientific theory or mathematical method;
(b) a literary, dramatic, musical or artistic work or any other aesthetic creation whatsoever;
(c) a scheme, rule or method for performing a mental act, playing a game or doing business, or a program for a computer;
(d) the presentation of information;
but the foregoing provision shall prevent anything from being treated as an invention for the purposes of this Act only to the extent that a patent or application for a patent relates to that thing as such.'
...1) European patents shall be granted for any inventions which are susceptible of industrial application, which are new and which involve an inventive step.
(2) The following in particular shall not be regarded as inventions within the meaning of paragraph 1:
(a) discoveries, scientific theories and mathematical methods;
(b) aesthetic creations;
(c) schemes, rules and methods for performing mental acts, playing games or doing business, and programs for computers;
(d) presentations of information
(3) The provisions of paragraph 2 shall exclude patentability of the subject-matter or activities referred to in that provision only to the extent to which a European patent application or European patent relates to such subject-matter or activities as such.
THE ORIENTATION PATENT
'1. A method of designing a roller cone bit, comprising the steps of:
(a) adjusting the orientation of at least one tooth on a cone, in dependence on an expected trajectory of said tooth through formation material at the cutting face, in dependence on an estimated ratio of cone rotation to bit rotation;
(b) recalculating said ratio, if the location of any row of teeth on said cone changes during optimization;
(c) recalculating the trajectory of said tooth in accordance with a recalculated value of said cone speed; and
(d) adjusting the orientation of said tooth again in accordance with a recalculated value of said tooth trajectory.'
(a) A very convenient way for designers to take full advantage of a computerimplemented calculation of geometries. (The motion over hole bottom of roller cone bit teeth is so complex that only a complex mathematical model and associated computer program can provide accurate design support.)
(b) Convenient calculation of tooth trajectory over the hole bottom during the period when the tooth engages into and disengages from the formation.
(c) The disclosed methods permit the orientation angle of teeth in all rows to be accurately determined based on the tooth trajectory.
(d) The disclosed methods permit the influence of tooth orientation changes on bit coverage ratio over the hole bottom to be accurately estimated and compensated.
(e) The disclosed methods also permit designers to optimally select different types of teeth for different rows, based on the tooth trajectory.
15 MR. BURKILL: Professor, I think the outcome of all this, and this
16 may be a slightly shocking proposal, is that actually pages 13
17 and 14 are the wrong way round and that the way to make sense
18 of it is that if the calculation proceeds with the full
19 simulation on page 14 first and then uses page 13 in order to
20 generate the figures ----
6 A. I agree that from an engineering point of view the procedure
7 by which you, first of all, run the full simulation for such
8 a length of time as is required to establish steady cutting.
9 From that simulation, you withdraw information on cone to bit
10 speed ratios and rate of penetration, probably averaged, and
11 that is not I think mentioned, but it would seem to me to be
12 sensible to average them, and then separately put that
13 information on cone to bit speed ratios into a kinematical
14 calculation which generates an initial bottom hole plot like
15 that in figures 3A, B, C and D from which the tooth
16 orientation could be decided. That I think is indeed
17 a logical explanation, but of course it is different from what
18 the flow diagrams show.
19 Q. Yes, I accept it requires cutting and pasting to transpose
20 pages 13 and 14, but from an engineering point of view, that
21 would actually be the way of achieving the figures at 3A, 3B,
22 3C and 3D. Is that right?
23 A. That would be one way of sorting out the position. There may
24 be others.
14 A. Well, my Lord, what I think is this. If we were starting from
15 scratch, we would have to read in the bit parameters, the
16 geometrical parameters, and the positions and details of the
17 teeth. We would then have to feed in the known angular rate
18 of bit rotation and details about the formation properties,
19 then start the kinematical calculation, which would tell the
20 computer which teeth are above and immediately adjacent to the
21 formation at the starting position so they would have to
22 establish the start position.
23 Then the time[s] stepping process would begin. As I tried
24 to describe this morning, each time set would be made.
25 A balance would be sought between upforces and downforces and
2 cone to bit speed ratios would be subjected to updating
3 according to the torsional statement of Newton's laws. This
4 process would be established to get dynamical equilibrium in
5 what is happening so that the drill is now in actual .... Of
6 course the weight on bit would have been specified. The drill
7 is now in the simulation, drilling steadily down into the
9 At that point, the cone to bit speed ratios would be
10 drawn out and averaged over the period of 10 seconds, or
11 however much is agreed, and then the bottomhole plane would be
12 constructed for the average trajectories with the average
13 properties for that motion; so it would then be a bottomhole
14 plane picture from which the teeth could be oriented whenever
15 required. The optimization would have to be built into this,
16 so it would then look at the results that have been achieved,
17 whether they be forces or volumes, or some other parameter,
18 and compare them with an objective requirement and would say,
19 "If not met, change one or more parameters, go back to the
20 beginning and run the whole simulation again."
Calculation of Cone/Bit Rotation Ratio 
The present application also teaches that the ratio between the rotational speeds of cone and bit can be easily checked in the context of the detailed force calculations described above simply by calculating the torques about the cone axis If these torques sum to zero (at a given ratio of cone and bit speed) then the given ratio is correct if not an iterative calculation can be per- formed to find the value of this ratio.
 However it should be noted that the exact calculation of the torque on the cones is dependent on use of a solid body tooth model as described above rather than a mere point approximation.
 Previous simulations of roller cone bits have assumed that the gage row is the 'driving" row which has no tangential slippage against the cutting face However this is a simplification which is not completely accurate. Accurate calculation of the ratio of cone speed to bit speed shows that it is almost never correct if mul- tiple rows of teeth are present to assume that the gage row is the driver.
 Changes in the tooth orientation angle will not themselves have a large immediate effect on the cone speed ratio However the tooth orientation affects the width of uncut rings and excessive uncut ring width can require the spacing of tooth rows to be changed Any changes in the spacing of tooth rows will probably affect the cone speed ratio.
'Calculating cutting depth, area, volume and forces for each [tooth] in cutting, Updating the hole bottom matrices based on the crater model for rocking being [drilled]. [Counting] the number of teeth […] cutting for cones and bit [in] any time step. Projecting the teeth force into cone and bit coordinates and getting the total cone and bit forces and moments. Calculating the specific energy for the bit.'
Construction of the claim.
'A method of designing a roller-cone bit, comprising the steps of:
(a) adjusting the orientation of at least one tooth on a cone, in dependence on an expected trajectory of said tooth through formation material at the cutting face, in dependence of an estimated ratio of cone rotation to bit rotation;
(b) recalculating said ratio, if the location of any row of teeth on said cone changes during optimization;
(c) recalculating the trajectory of said tooth in accordance with a recalculated value of said cone speed; and
(d) adjusting the orientation of said tooth again, in accordance with a recalculated value of said tooth trajectory.'
6 looked at the various outputs that are referred to in 10 and
7 11. Is that correct?
8 A. I most likely would have, yes.
'10. I cannot remember exactly what 1 looked at in lDEAS when I designed this cutting structure. However, I would have looked at the "insert" output for each row of each cone in the analysis phase of IDEAS because the teeth on my design were oriented. Although I cannot remember doing so, I would have probably attempted to ensure that the red areas (indicating contact with the formation) were not concentrated in one small area on the output, by rotating the tooth to ensure that contact with the formation was distributed across as much of the tooth as possible.
11. I may also have viewed the 'bottom hole plot' and the 'animation' design tools within IDEAS. The animation tool shows the cutting structure design in rotation, and can assist in detecting gross design issues and errors in the design process. For example, if I had made a mistake in translating my design from Pro/E to IDEAS that mistake could be quickly detected by looking at the animation. Predominantly, this would be my reason for pulling up the animation window. This window also allows the user to visualize occurrences of tracking. However, it would require the user to watch the simulation with a close eye throughout the entirety of the simulation in order to understand whether a tooth is tracking often enough to warrant alteration, so I did not think it was the best means for detecting tracking and altering tooth orientation. I would not have used the animation window to alter tooth orientation on my design. The bottom hole plot can also be used to detect tracking but is not very useful for determining tooth orientation. If tracking were to occur on one or more of the rows, then a pitch break may have been added to prevent this from happening. I would have relied upon the "insert" output as means for altering tooth orientation. I say this because the "insert" output is more or less a summary of all the occurrences of contact with the simulated formation of all the teeth for a given row.
12. During the design process I would also have looked at the Fz_Aver information for each of the rows and cones as I changed the crest length, orientation, location and/or crest width of the milled teeth, so that I could see how my changes were affecting the ratio of cone load to bit load. This is a difficult task as, more often than not, a design yielding a faster ROP would also yield more unbalanced cones. It is a general assumption by bit designers that if you distribute the forces acting on each cone disproportionately, then one of the bearings of the bit may fail sooner than if they all took the same load. Therefore, I always like to try to get the milled tooth bits that I design to be as close to being balanced as I can manage, while still taking into account the need for as fast an ROP as possible. '
'The Patent provides no or no sufficient disclosure as to how to perform the recited adjustments: how to determine or recalculate the expected trajectory or the relative positions of the bit and formation that would be required; how to estimate or recalculated the recited ratio of cone rotation to bit rotation; how to determine the cone speed; or how to account for the physical aspects of drilling into a formation in particular how to determine and apply the physical properties of the formation and/or the bit.'
(a) the errors and difficulties in Figs 1A-1C;
(b) the need to calculate the transformation matrices required for the kinematic calculations, including ascertaining that the equations given contain errors and correcting them;
(c) the lack of a force model, which must be created from scratch; if a crossreference to the Force Balancing Patent is permissible as Halliburton suggests, the skilled person must also deal with the incorrect description of the force model as a single element model, and the other inadequacies of the Force Balancing patent, including the need to develop experiments to obtain data from real life; this would involve designing and building the specialist equipment needed and thereafter carrying out all the required experiments;
(d) the calculation of the cone to bit speed ratio;
(e) the failure to take account of the shape of the tooth on the P1 – P2 line in cone coordinates and its effect on the calculated line of trajectory;
(f) alternatively to (e): the failure to mention or describe the different transformation of the trajectory from hole coordinates to cone coordinates.
'Mr Hall's evidence on torque balance was at Hall I para 34, and Hall II paras 70, 75 and 77. He was XX'd on Day 3 at 439 et seq., more especially from 451. The thrust of his evidence was that:
- Rate of penetration and cone speed are interrelated.
- You solve for them by an iterative process.
- You would initially assume an advance for the bit, and iterate on that to find the rate of penetration.
- Thereafter, having that, you iterate on torque balancing to check the cone speed. o If necessary, you then go back and iterate penetration again.
As to this, see passages starting at 456/15, 457/12, and at 460:'
12 Q. We have assumed an ROP and a cone to bit speed ratio.
13 A. We determine an ROP or a penetration. You would assume an
14 advance for the bit. You would have to then calculate what
15 forces that would produce, balance those off against the
16 weight on bit to determine if they were correct, and you would
17 have to iterate first on the degree of advance.
18 Q. The ROP cannot be determined entirely by a static test
19 involving simply omitting the bit to rest on top of the rock.
20 A. That is correct.
21 Q. One is inevitably making an assumption about the ROP and the
22 cone to bit speed ratio when one does this exercise of
23 determining the forces on movement and thereafter assessing
24 whether it talks about the cone axes amount to 0 or not.
25 A. Yes.
5 MR. JUSTICE PUMFREY: Yes, of course. Do I understand you to be
6 saying therefore that if I sit there fondly imagining that
7 what I have been doing is looking at the trajectory as
8 projected on to the bottomhole plot, and if I thought that
9 what the patent was talking about was orientating the tooth so
10 as -- let us be normal -- to get maximum scraping effect to
11 the trajectory on the bottomhole plot, I would have got it
12 seriously wrong, because, as I understand your evidence, what
13 in fact you feel the author is telling you to do is to look at
14 that line as it appears in cone coordinates effectively on the
15 surface of the cone therefore and projected on to the surface
16 of the cone so that I will find notionally on my cone a nice
17 line drawn through the tooth, and when I find that line drawn
18 through the tooth, I twist my tooth until it is normal to that
19 line projected on to the surface of the cone. Have I
20 understood your evidence correctly?
21 A. Yes, my Lord, you have. That I understand to be the
23 Q. And the line that is projected on to the surface of the cone
24 is the projection of a straight line in space joining the
25 entry and exit points in cone coordinates. Is that also
3 A. It is a straight line on the surface of the cone. P1 may
4 not ----
5 Q. Straight line on the surface of the cone?
6 A. That is the way in which it is expressed. It is a line in
7 3-dimensional space. You are absolutely correct, my Lord; it
8 is curved, but it is approximated in the calculation I gave in
9 my appendix as a straight line.
10 Q. It is the point joining the entry and exit points in cone
11 space in a space on the surface of the cone.
12 A. Yes. To be precise, it has to pass through the cone surface
13 in order to join P1 and P2.
15 Q. Mr. Burkill suggested, as I understood him during the course
16 of his submissions to my Lord, that this point was simply
17 addressed by having a single crest point.
18 A. Yes.
19 Q. But that is not an answer, is it, Mr. Hall, because if P1
20 equals P2, then there is no pair of points between which
21 a line can be drawn to determine the trajectory?
22 A. Not so. It is not at all so. In fact, actually using one
23 single point is what I would probably guide my modeller to do.
24 The reason for that is, as I stated first, P1 and P2 are
25 two points on the hole bottom initially, not on a cone. So if
2 you have a tooth with a point, it will begin contact with
3 a hole bottom in a location, but due to the scraping and
4 gouging and traversing, it will leave contact at a different
5 location. If I now take a snapshot of that entry and exit
6 point and project it on to my cone coordinates system, it is
7 not a single point. It is a path. It is not one single
8 point. It was caused by one single point on the cone, but it
9 is not a result of one single point in the formation. In
10 fact, tracking one single point would seem to be a totally
11 reasonable modelling approach, which is what I would likely
12 guide my modeller to do to remove this sort of possibility.
13 Q. With great respect, this is simply inconsistent. What you are
14 suggesting, Mr. Hall, is inconsistent with what is described
15 in paragraph 51 because P1 and P2 are different points in cone
17 A. Once they have been transposed into the cone coordinates.
18 They initiated as an entry point and exit point, however, in
19 the formation. They are then transposed to cone coordinates.
'156. As already stated above, the invention is based on an underlying realisation that the motion of the bit can and should be modelled mathematically. If the cone/bit rotation speed can be found, then the motion of the cones and teeth can be established. From that, the actual trajectory of the tooth through the formation can be determined.
157. The invention provides that the tooth orientation may then be adjusted by reference to its trajectory. If [when] the location of a row changes during the design process, a new trajectory is established, which is in dependence on a recalculated estimate of the cone/bit speed ratio and this new trajectory is used as the basis for a further orientation of the tooth.
The Ma Book
'the patented program for optimizing the tooth (or insert) crest direction has great interest for the bit designer, manufacturer and user. If the tooth or insert is not symmetrical about its own center line, its crest is in a certain direction. This direction has considerable effect on the scraping area and the rock breaking effectiveness of the bit. This direction, however, was formerly always along the generatrix [i.e. parallel to the axis] of the roller cone, until the new type of bit was designed by the author's research group. The ROP of these bits with the optimised tooth deflection angle are much improved in the field tests.'
'our computer simulation program combines all the necessary data runs all the teeth of bit step by step and predicts the ROB, the sidecutting ability and wearability for specific bit-formation set. If the results are not fully satisfactory, the related factors will be adjusted and the optimum design will be approached step by step.'
(a) Calculating the tooth trajectory based on a cone/bit speed ratio.
(b) Using the trajectory so calculated to orientate the teeth.
They insist, however, that there is no disclosure of an iterative recalculation of the cone/bit speed ratio. In this they are right. I should say, however, that I consider a recalculation of the cone/bit speed ratio every time the design changes as an obvious thing to do, if the change to the design might change it.
US 5,197,555 (Estes)
VALIDITY—NOT A PATENTABLE INVENTION
SUMMARY OF CONCLUSIONS
Annex A—cross references
" The following patent application describes roller-cone drill bit design methods and optimizations which can be used separately from or in synergistic combination with the methods disclosed in the present application. That application which has common ownership inventorship and effective filing date with the present application is Application no._____ filed 31 August 1999 entitled "Force Balanced Roller Cone Bits Systems Drilling Methods and Design Methods" (atty. docket no. SC-9825), claiming priority from U.S. provisional application no 60/098 466 filed 31 August 1998. That nonprovisional application, and its provisional priority application, are both hereby incorporated by reference."
" U.S. Patent Application____, filed 31 August 1999 (issued as US patent 6,095,262), entitled "Roller-Cone Bits, Systems, Drilling Methods, and Design Methods with Optimisation of Tooth Orientation" (Atty. Docket No. SC-98-26), and claiming priority from U.S. Provisional Application 60/098442 filed 31 August 1998, describes roller cone drill bit design methods and optimizations which can be used separately from or synergistic combination with the methods disclosed in the present application. That application has common ownership, inventorship, and effective filing date with the present application. and its provisional priority application, are both incorporated herein by reference."
(ii) if the reference document was not available to the public on the date of filing of the application, it can only be considered if (see T 737/90, not published in OJ):
(a) a copy of the document was available to the EPO on or before the date of filing of the application; and
(b) the document was made available to the public no later than on the date of publication of the application under Art. 93 (e.g. by being present in the application dossier and therefore made public under Art. 128(4)).
(1) Publication under Article 21 of the Cooperation Treaty of an international application for which the European Patent Office is a designated Office shall … take the place of the publication of a European patent application and shall be mentioned in the European Patent Bulletin…