Expert Declaration in IPR2016-01786 & IPR2016-01827
`for U.S. Patent No. 8,851,951 by Rutledge entitled
`“Sucker Rod Apparatus and Method”
`
`Prepared by:
`
`Gary R. Wooley
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`Wooley & Associates, Inc.
`
`3100 S. Gessner, Suite 325
`Houston, Texas 77063
`Phone 713.781.8974
`Email gary@wooley.com
`
`Prepared for:
`
`Morgan, Lewis & Bockius LLP
`
`1000 Louisiana St., Suite 4000
`Houston, Texas 77002-5006
`Phone 713.890.5165
`
`15 September 2016
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`Wooley & Associates, Inc.
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`Page 1 of 146
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`Petitioners' Exhibit 1010
`John Crane v. Finalrod
`IPR2016-01786
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`TABLE OF CONTENTS
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`I.
`
`II.
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`III.
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`Page
`Introduction ..................................................................................................... 1
`A. 
`Background and Qualifications ............................................................ 1
`B. 
`Engagement .......................................................................................... 2
`C.  Materials Consulted .............................................................................. 4
`Basic Oil Well Sucker Rods ........................................................................... 5
`A. 
`Field Use of Oil Sucker Rods ............................................................... 5
`B. 
`Overview of Forces Encountered During Sucker Rod Use ............... 10
`Common Problems to Address in the Field ....................................... 17
`C. 
`Legal Standards for Patentability ................................................................. 28
`A.  Anticipation ........................................................................................ 28
`Obviousness ........................................................................................ 29
`B. 
`IV. Overview of U.S. Patent 8,851,951 to Rutledge .......................................... 32
`A. 
`Rutledge ’951 Patent Effective Filing Date ....................................... 32
`Overview of the Rutledge ’951 Patent ............................................... 32
`B. 
`C. 
`Prosecution History of the Rutledge ’951 Patent ............................... 36
`V. 
`Relevant Field of Art .................................................................................... 39
`Level of Ordinary Skill ................................................................................. 40
`VI.
`VII. Claims of the Rutledge ’951 Patent .............................................................. 41
`VIII. Claim Constructions ..................................................................................... 48
`A. 
`Claim Construction Standard ............................................................. 48
`Construction of The Rutledge ’951 Patent Claim Terms ................... 49
`B. 
`IX. Background Invalidity Analysis ................................................................... 57
`A. 
`Scope and Content of the Prior Art .................................................... 57
`The ’951 Rutledge Patent Claim Sets ................................................ 57
`B. 
`C. 
`Overview of the Prior Art Patents ...................................................... 59
`D.  Motivation to Combine The Prior Art Patents ................................... 61
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`D. 
`E. 
`F. 
`
`G. 
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`H. 
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`TABLE OF CONTENTS
`(continued)
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`Page
`
`B. 
`
`C. 
`
`
`X.  Ground 1: Claims 4, 7, 8, 14, 15, 17, 21, 22, 35, 47, and 60-69 are
`unpatentable under 35 U.S.C. §103 as obvious over the Rutledge ’431
`Patent in view of Iwasaki .............................................................................. 63 
`A. 
`The Rutledge ’431 and Iwasaki Patents Disclose Each Element
`of Claims 4, 7, 14, and 21 .................................................................. 63 
`The Rutledge ’431 Patent Discloses Each Additional Element
`of Claims 8 and 35.............................................................................. 93 
`Iwasaki Discloses Each Additional Element of Claims 15 and
`22 ........................................................................................................ 99 
`Iwasaki Discloses Each Additional Element of Claim 17 ............... 101 
`Independent Claim 60 ...................................................................... 104 
`The Rutledge ’431 and Iwasaki Patents Discloses Each
`Additional Element of Claims 61 and 62 ......................................... 118 
`The Rutledge ’431 and Iwasaki Patents Discloses Each
`Additional Element of Claim 63 ...................................................... 122 
`Claims 65 – 69 Are Obvious For The Same Reasons As Claims
`4, 7, 14, and 21 ................................................................................. 128 
`XI.  Ground 2: Claims 6, 50, 52, 57, and 59 are invalid under 35 U.S.C.
`§103 as obvious over the Rutledge ’431 and Iwasaki Patents further in
`view of Anderson ........................................................................................ 130 
`A.  Anderson Discloses Each Additional Element of Claims 6 and
`50 ...................................................................................................... 131 
`Anderson Discloses Each Additional Element of Claim 52Error! Bookmark not d
`B. 
`C. 
`Anderson Discloses Each Additional Element of Claim 57 ............ 135 
`D.  Anderson Discloses Each Additional Element of Claim 59 ............ 136 
`XII.  Conclusion .................................................................................................. 137 
`XIII.  Appendix ..................................................................................................... 139 
`A. 
`Resumé for Gary R. Wooley ............................................................ 139 
`B. 
`List of Recent Wooley Testimony ................................................... 140 
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`I.
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`Introduction
`A. Background and Qualifications
`1. My name is Gary R. Wooley. I am currently President of Wooley &
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`Associates, Inc., a petroleum and mechanical engineering consulting firm. A copy
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`of my current curriculum vitae more fully setting forth my experiences and
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`qualifications is submitted herewith in the Appendix to this Report.
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`2.
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`I have more than 40 years of petroleum industry experience most of
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`which has been in the upstream sector dealing with drilling, completions,
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`production, reservoir performance and other subjects including artificial lift such as
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`rod pumping. I received my university training at Louisiana State University in
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`Baton Rouge, Louisiana and was awarded a B.S. in Mechanical Engineering in
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`1969, an M.S. in Engineering Science in 1970 and Ph.D. in Engineering Science
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`with minors in Applied Mathematics and Mechanical Engineering in 1972.
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`3.
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`I was trained in the petroleum industry by four major oil companies,
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`Shell, Chevron, Humble (Exxon) and ARCo and have been a consulting engineer
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`since 1978 with clients that include all of the major oil companies, service
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`contractors and supply companies and many smaller companies. I have conducted
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`laboratory and field tests, developed computer models, and designed and evaluated
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`downhole oilfield equipment. I have worked on multiple artificial lift projects
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`including rod pumps.
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`4.
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`This report contains facts, opinions and conclusions based on my
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`training and experience and the information reviewed at the time of this writing.
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`My resumé is also presented in the Appendix along with my recent testimony.
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`5.
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`This report contains my general opinions, but obviously not all details
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`are included. If asked questions on these facts and opinions or other subjects, I may
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`have opinions not specifically listed herein. There may be documents and
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`testimony that support my opinions that are not included herein.
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`6.
`
`As additional information is examined, these facts, opinions and
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`conclusions may be changed and/or supplemented. Upon review of additional
`
`documents and testimony I may supplement or revise my opinions. Also, after
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`reading reports by defendants’ experts, I may have opinions to rebut those expert
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`opinions.
`
`B.
`7.
`
`Engagement
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`I have been retained by John Crane, Inc. and John Crane Production
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`Solutions, Inc. (“John Crane”) in connection with the Petitions for Inter Partes
`
`Review (“IPR”) of U.S. Patent No. 9,045,951 (“the ’951 Patent”), Case Nos.
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`IPR2016-01786 and IPR2016-01827. I submit this declaration in support of John
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`Crane’s requests for IPR of the ’951 Patent. I understand that my testimony will
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`be submitted for the purposes of testimonial evidence in IPR2016-01786 and
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`IPR2016-01827 to be considered before the Patent Trial and Appeal Board
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`(“PTAB”). I previously submitted a declaration in IPR2016-00521 in support of
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`John Crane’s request for IPR of the ’162 Patent—the ’951 Patent’s parent patent—
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`which I understand was not instituted for review.
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`8.
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`I am not an employee of John Crane, or any affiliate or subsidiary
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`thereof.
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`9.
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`I am being compensated at my normal hourly rate of $520 per hour.
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`My compensation is in no way dependent upon the outcome of the IPR.
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`10.
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`I have been asked to provide my opinions relating to the validity of
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`the ’951 Patent. Specifically, I have been asked to provide my opinion regarding:
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`(i) the level of ordinary skill in the art to which the ’951 Patent pertains, and (ii)
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`the patentability of claims 4, 6-8, 14-15, 17, 21-22, 35, 50, 52, 57, 59-63, and 65-
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`69 of the ’951 Patent.
`
`11. The opinions expressed in this declaration are not exhaustive of my
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`opinions on the validity of claims 4, 6-8, 14-15, 17, 21-22, 35, 50, 52, 57, 59-63,
`
`and 65-69 of the ’951 Patent. Therefore, the fact that I do not address a particular
`
`point, or my another unchallenged claim of the ’951 patent, should not be
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`understood to indicate any agreement on my part that any claim otherwise
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`complies with the validity and patentability requirements.
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`C. Materials Consulted
`12.
`In preparing this declaration, I reviewed the following material,
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`which, in conjunction with my personal experience in the relevant field, provide
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`the basis of my opinions in this Report:
`
`a)
`
`b)
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`c)
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`John Crane’s Petition for Inter Partes Review;
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`The ’951 Patent” (Ex. 1001);
`
`The ’951 Patent File History (Ex. 1002);
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`d) U.S. Patent No. 8,113,431 (“Rutledge ’431 Patent”) (Ex. 1003);
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`e)
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`f)
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`g)
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`U.S. Patent No. 4,475,839 (“Strandberg”) (Ex. 1004);
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`U.S. Patent No. 4,662,774 (“Morrow”) (Ex. 1005);
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`U.S. Patent No. 8,113,277 (“Rutledge ’277 Patent”) (Ex. 1006);
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`h) U.S. Patent No. 4,822,201 (“Iwasaki”) (Ex. 1007);
`
`i)
`
`j)
`
`k)
`
`l)
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`U.S. Patent No. 4,919,560 (“Rutledge ’560 Patent”) (Ex. 1008);
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`U.S. Patent No. 5,253,946 (“Watkins”) (Ex. 1009);
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`Side-by-Side Comparison of the ’951 Patent claims (Ex. 1011);
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`U.S. Patent No. 4,401,396 (“McKay”) (Ex. 1012);
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`m) U.S. Reissue Patent No. RE32,865 (“Rutledge ’865 Patent”)
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`(Ex. 1013);
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`n) U.S. Patent No. 7,730,938 (“Rutledge ’938 Patent”) (Ex. 1014);
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`o)
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`Edward L. Hoffman, Finite Element Analysis of Sucker Rod
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`Couplings with Guidelines for Improving Fatigue Life, Sandia
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`National Laboratories, (Jul. 11, 1997) (“Hoffman Article”; Ex.
`
`1015);
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`p) U.S. Patent No. 8,062,463 (“Rutledge ’463 Patent”) (Ex. 1016);
`
`q) U.S. Patent No. 6,886,484 (“Thomas”) (Ex. 1017);
`
`r)
`
`s)
`
`t)
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`U.S. Patent No. 4,653,953 (“Anderson”) (Ex. 1018);
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`U.S. Patent No. 8,851,162 (“’162 Patent”) (Ex. 1023);
`
`Patent Owner’s Preliminary Response in in IPR2016-00521
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`(Paper 6); and
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`u) Decision Denying Review in IPR2016-00521 (Paper 7)
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`
`II. Basic Oil Well Sucker Rods
`A.
`Field Use of Oil Sucker Rods
`13. The ’951 Patent is directed to designs for sucker rod end fittings that
`
`are used to connect one or more oil sucker rods. Ex. 1001, Abstract. By way of
`
`background, a sucker rod pump (illustrated below) operates to bring underground
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`oil to the earth’s surface.
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`Ex. 1007, at 9.
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`14.
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`In the above exemplary implementation, the sucker rod pump has a
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`primary drive motor attached to a flywheel and a crank arm. Attached to the crank
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`arm is a Pitman Arm, which links the crank arm to a walking beam. The walking
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`beam has a horse head at its other end. During operation, the primary drive motor
`
`turns the flywheel, such that the arms interact to convert the rotary motion of the
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`drive motor to a translational up and down pumping motion of the horse head. It’s
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`this pumping motion of the horse head that drives the pumping of the sucker rod
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`string.
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`15. At the end of the sucker rod string is one or more valves that are used
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`to maintain the direction of the oil flow. These valves may take a number of
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`forms, but they are often just a ball in a cage that allow the oil to flow into the
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`valve during the down stroke, and then plug the hole in the cage and restrict the
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`reverse flow of oil on the upstroke. Thus, the successive downward and upward
`
`stroke of the horse head causes extraction of oil by pushing it up the rod string
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`from the underground reservoir.
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`16.
`
`In order to recover oil from deep oil wellbores, it is well known in the
`
`art to create a “string” of sucker rods by connecting multiple sucker rods end-to-
`
`end using sucker rod end fittings. As the prior art Rutledge ’277 Patent, U.S.
`
`Patent No. 8,113,277 (Ex. 1006) explains:
`
`It is well known in the art to use sucker rods to actuate a downhole
`pump to recover oil from a wellbore. Typically, a series of sucker rods
`are connected end to end to form a sucker rod string, which extends
`from the pump drive 10 to the pump 14 (FIG. 1). It should be
`appreciated that pump drive 10 is typically a pump jack (i.e. a beam
`pump system) or other known pump drive. Further, downhole
`pump 14 is typically a conventional pump well known in the art. It
`should be appreciated that although fiberglass or composite sucker
`rods are light weight, they are typically connected by metallic end
`fittings 30 which add to the weight of the string and can be a
`considerable factor in a very deep wellbore as the pump drive must
`overcome the weight of the sucker rod string, including the metallic
`end fittings 30 in order to acuate [sic] the downhole pump 14. It
`should be appreciated that the sucker rod string can be made up of
`many rods that are approximately thirty-seven (37) feet in length, the
`string can comprise one single continuous rod, or a few continuous
`rods which can be hundreds of feet in length or even a thousand or
`more feet in length. Regardless of the length of the sucker rod, it is
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`preferably assembled, as described herein, with an end-fitting 30 as
`illustrated in FIGS. 4 or 4A.
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`Ex 1006, 1:61 – 2:17; see also id., Fig. 1:
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`
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`17. Thus, it was well-known in the art well before the time of the ’951
`
`Patent to create sucker rod strings by connecting hundreds, sometimes thousands
`
`of feet of fiberglass sucker rods end-to-end. Since the 1970s, these sucker rod
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`strings have been made of fiberglass. See Rutledge ’865 Patent, Ex. 1013 (filed
`
`1979 and describing fiberglass sucker rod strings).
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`18. Since the time that sucker rod strings were first used, a key
`
`consideration has been sucker rod fatigue at the end fitting. In material sciences,
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`fatigue refers generally to the weakening of a material caused by repeatedly
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`applied loads. When dealing with sucker rod strings, fatigue results from the
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`progressive and localized structural damage that occurs when the sucker rods are
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`subjected to cyclic loading of the reciprocating environment of pumping oil wells,
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`i.e., up stroke and down stroke of the sucker rod string. A brief introduction to the
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`forces that interplay to result in failure due to sucker rod fatigue are described
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`below. However, it is should be noted that this discussion is merely exemplary and
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`a person of ordinary skill in the art at the time of the ’951 Patent’s filing
`
`(“POSITA”) would understand that fatigue failure of a fiberglass sucker rod is
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`caused by changing forces on the rod, environmental considerations such as
`
`temperature, and the material properties of the fiberglass sucker rod.
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`B. Overview of Forces Encountered During Sucker Rod Use
`19.
`In some of the fiberglass sucker rod and end fitting prior and current
`
`art the forces acting on and the stresses in the sucker rod and the end fitting are
`
`described in an imprecise manner. I provide an overview of several of the forces
`
`commonly encountered during use of sucker rod strings in this section in effort to
`
`clarify some of these concepts. It is important to keep clear that forces are vector
`
`quantities that have a magnitude and direction, and stress is a tensor that has
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`principal and shear components. Discussing one component of force or stress, for
`
`example, when discussing end fitting designs, is of value, but not sufficient to
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`make decisions about deformation and failure of material. A POSITA would
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`understand that there are additional forces and considerations interacting with the
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`end fitting and sucker rod that would also affect the force distribution at any
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`particular point.
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`20.
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`In the cylindrical coordinate system that is commonly used for
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`discussion of sucker rods and end fittings, generally the principal directions used
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`are axial (along the axis of the rod, vertical in vertical wells), radial (perpendicular
`
`to the rod axis, horizontal in vertical wells) and circumferential or tangential
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`(perpendicular to radial direction and along the circumference of the rod or fitting,
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`horizontal in a vertical well). I note that not all of the prior art that I have reviewed
`
`utilize these terms consistently. Where possible, I have endeavored to identify
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`these inconsistencies in use in the prior at, and to use the foregoing terminology
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`consistently throughout my opinions.
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`21. Another issue that requires careful discussion is material behavior.
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`Steels such as those used to manufacture end fittings can often be characterized
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`with a bilinear stress-strain curve that changes slope at the yield point. Except in
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`extreme circumstances the steel stress-stain curve is reasonably assumed to be
`
`independent of temperature, pressure and environment. In most steels the
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`mechanical properties described by the stress-strain curve are isotropic. Of course
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`introduction of hydrogen sulfide can significantly affect the performance of steel,
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`and extremely high temperatures can alter the stress-strain curve for steel. In
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`contrast, the material properties for fiberglass like that used to manufacture sucker
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`rods are significantly different that steel. A stress-strain curve for fiberglass may
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`have a linear portion at low stress or may not, depending on temperature and time.
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`Elevated temperature reduces the stiffness of fiberglass, and the effects of creep
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`make the response of fiberglass dependent on the rate of loading. Another issue is
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`the properties of fiberglass are usually anisotropic, i.e. different in axial, radial and
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`circumferential directions, depending on the method of manufacture and materials
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`used. Thus, in discussing the forces encountered during operation of the pumping
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`unit, it is important to keep in mind that the steel end fitting responds differently to
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`the reciprocating forces of pumping than the fiberglass sucker rod itself.
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`22. Among the prior art the terminology for forces encountered during
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`operation of a pumping unit using a sucker rod string to extract oil include
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`compressive forces on the end fitting, tensive forces, shear forces, negative load
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`forces, radial forces, back pressure forces, and shock load. As mentioned, the prior
`
`art often uses these terms in an imprecise manner, including by misidentifying the
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`primary force at play or by neglecting to give a more complete picture of the force
`
`components that are interacting with each other at any given moment. In an effort
`
`to promote consistency in terminology throughout my discussion of the prior art, I
`
`provide the following non-exhaustive explanation of force terms as they are used
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`in the prior art and the ’951 Patent.
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`23. Compressive Forces: Compression is the application of forces at
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`different points on a material or structure that tend to compact or reduce the
`
`volume of the material or structure. In the context of sucker rod strings,
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`compressive forces may be axial, radial, or circumferential in direction.
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`24. Because the pump must work against the weight of the rod string and
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`the hydraulic head of the fluid in the production tubing string, which head
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`pressures can be extremely high dependent upon the depth of the well, high axial
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`loads or forces are present during both the upstroke and down stroke parts of the
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`cycle, resulting in varying stresses at each point in the sucker rods and end fitting
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`in this reciprocating environment.
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`25. Radial Compressive Forces: Radial compressive forces are
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`compressive forces acting in the radial direction. In the context of sucker rod
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`strings, radial compressive forces are applied to the sucker rod by the wedges from
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`the end fitting being squeezed inward by the application of axial tensile load to the
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`sucker rod during pumping.
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`26. Axial Compressive Forces: Axial compressive forces are
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`compressive forces acting in the axial direction. In the context of sucker rod
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`strings, axial compressive forces are applied to the sucker rod on the downstroke
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`during pumping. In the upper portion of the sucker rod string, the downstroke may
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`reduce tension but not achieve compression
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`27. Circumferential or Tangential Compressive Forces:
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`Circumferential or tangential compressive forces are compressive forces acting in
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`the circumferential direction. In the context of sucker rod strings, circumferential
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`compressive forces are applied to the sucker rod by the wedges from the end fitting
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`28. Tensile Forces: Tensile forces are forces that tend to expand or
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`increase the volume of a material or structure. Similar to compressive forces,
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`tensile forces may be axial, radial, or circumferential.
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`29. Shear Forces: Shear forces or shearing refers generally to the forces
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`that are applied to the wedge shaped formations and which tends to separate the
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`wedge shaped portions from the body of the sucker rod.
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`30. Negative Load Forces: Several of the prior art Rutledge patents refer
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`to “negative load forces.” Based on my reading of the prior art Rutledge patents,
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`these references appear to associate negative load forces with axial compressive or
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`reduced tensile forces imparted during the down stroke of the pump. During up
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`stroke, the pump must work against the weight of the rod string as well as the
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`weight of the fluid within the rod string. This weight places a tensile load on each
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`respective sucker rod that equals the weight of the number of rods that the sucker
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`rod is supporting below.
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`31. During down stroke, however, the axial load and forces decrease as
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`the pump moves downward often to near zero and not uncommonly to a negative
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`tensile load, i.e. into compression. Thus, negative load forces could also refer to
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`the compressive axial forces imparted on the end fitting during down stroke in the
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`lower part of the sucker rod string if the pump moves downward quickly enough.
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`32. These negative load forces can also be exacerbated when using fiber
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`sucker rod, which have been commonly used in the industry for decades. As
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`another prior art Rutledge Patent, U.S. Reissue Patent No. RE32,865 (“Rutledge
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`’865 Patent”; Ex. 1013), explains “fiberglass sucker rod construction[s] . . .
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`impart[] an elasticity to the sucker rod string not found in conventional all-steel
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`sucker rods. In a reciprocating environment, this elasticity inherent in pre-stressed
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`fiberglass, results in an increased effective stroke length, and an increased stroking
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`force over that of a steel rod having a comparable surface stroke.” Ex. 1013, 4:64
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`– 5:2. The Rutledge ’865 Patent explains that this effect is similar to stretching a
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`rubber band, where the lower rods in the sucker rod string experience a stroke
`
`length greater than those of the upper end of the sucker rod string. Id. at 5:2-9.
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`Thus, the elastic nature of the sucker rod string can increase the potential for
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`negative load forces depending on the rate of reciprocation and sucker rod
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`properties and dimension.
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`33. Many of the prior art Rutledge patents appear to also refer to the
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`compressive force applied by the end fitting to the sucker rod during upstroke as
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`“negative” load. For example, prior art Rutledge Patent, U.S. Patent No. 8,113,277
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`(“Rutledge ’431 Patent,” Ex. 1003) states that “Negative load refers to forces
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`acting on the side of the wedge opposite from the gripping side of the wedge
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`describes a wedge shaped design.” Ex. 1003, 2:29-31. The Rutledge ’431 Patent
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`also explains that “Negative load is very destructive to the wedges of prior art
`
`designs, causing catastrophic shear failure of the wedge.” Id.at 2:31-33 (emphasis
`
`added).
`
`34. Back Pressure Forces: The ’951 Patent makes reference to “back
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`pressure” forces. Back pressure typically refers to a pressure that opposes the flow
`
`of a fluid in a confined place, such as a pipe. However, the ’951 Patent does not
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`appear to use back pressure in this sense. The ’951 Patent refers to a back pressure
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`exerted on the sucker rod end fittings and the wedge system formed therein. In
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`particular, the ’951 Patent describes “the wedge system 110 of the present
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`disclosure greatly enhances the stability of the sucker rod 10 and ability of the fiber
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`composite rod 200 and end fitting 100 combination to accept enhanced
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`compressive and back pressure forces associated with the reciprocating
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`environment in which the sucker rods 10 are used.” Ex. 1001, 5:35-40 (emphasis
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`added). A POSITA would understand “reciprocating environment” to refer to the
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`cyclic upward and downward stroke of the pump and string of sucker rods. Thus,
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`as used in the context of the ’951 Patent, a POSITA would understand “back
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`pressure forces” to encompass the compressive forces imparted by the axial tensile
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`load during reciprocation, similar to the “negative” forces described by the
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`Rutledge ’431 Patent. See Ex. 1003, 3:5-14 (“Wedges transmit the compressive
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`and tensing forces of pumping from the steel connector to the fiberglass rod and
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`vice-versa. . . . Essentially, the metal end fitting squeezes the deformations in the
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`adhesive when compressive and back travel forces are applied to the
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`construction.”) (emphases added).
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`35. Shock Load Forces: A shock load refers generally to the force that
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`results when an object suddenly accelerates or decelerates. As one prior art
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`Rutledge patent explains, “when a shock load occurs that creates a negative load,
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`the wedge has the ability to absorb the negative load forces and to thereby resist
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`failure of the rod connection.” Ex. 1003, 2:31-37. Thus, generally speaking, shock
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`loads are one factor that can contribute to negative load forces.
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`C. Common Problems to Address in the Field
`36. The above discussion of forces encountered during sucker rod use
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`provides a brief overview of the forces encountered during design of sucker rod
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`end fittings. It should be noted, however, that this discussion is merely exemplary
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`and a POSITA would understand that failure due to sucker rod fatigue is a factor of
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`many of these forces and environmental considerations, such as by changing forces
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`on the rod, changing temperature, and the material properties of the fiberglass
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`sucker rod. Accordingly, a POSITA would understand that these forces may
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`interact in various end fitting designs in varying ways, which makes sucker rod
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`fatigue difficult to predict without conducting expensive fine element analyses or
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`laboratory or field tests. Thus, a POSITA would generally be motivated to test end
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`fitting designs having even slight modifications to their design to determine
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`whether they impact failure due to sucker rod fatigue. That said, a number of
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`predominant views with respect to sucker rod fatigue and end fitting design have
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`emerged within the industry and would have been well-known to a POSITA at the
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`time of the ’951 Patent’s filing.
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`37.
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`In particular, it is readily apparent and widely known to those working
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`in the petroleum industry that failure due to sucker rod fatigue most often occurs in
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`the portion of the sucker rod that is encased in the end fittings connecting the ends
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`of two adjacent rods. It has also been widely known since at least the 1970s, as
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`illustrated by the prior art Rutledge ’865 Patent (Ex. 1013), that using epoxy wedge
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`systems within the interior wall of the end fitting, as opposed to using a linear
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`surface, greatly reduces failure due to sucker rod fatigue in the end fitting. Wedge
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`systems, akin to that described by the prior art Rutledge ’865 Patent, have been a
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`dominant design for decades. Since this time, many of those skilled in the art have
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`sought to reduce failure due to sucker rod fatigue by varying various parameters of
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`the wedge system, including length of the wedge (including the length of the
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`leading and trailing edge), the slope of the wedge’s incline, both on the trailing
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`edge and leading edge, number of wedges, configuration of the wedges, and their
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`respective sizes and shape.
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`38. An article published by Edward L. Hoffman, entitled Finite Element
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`Analysis of Sucker Rod Couplings with Guidelines for Improving Fatigue Life,
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`Sandia National Laboratories, published in 1997 (“Hoffman Article”; Ex. 1015),1
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`identified three approaches to improving the fatigue resistance of threaded sucker
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`rod couplings: (1) decrease the nominal alternating stress amplitude by increasing
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`1 I note that the Hoffman Article discusses threaded connections used in sucker rod
`string designs. However, many of the design principles (for example, minimizing
`stress concentrations) are equally applicable to wedge end fittings and are
`confirmed as a central consideration in many of the prior art patents identified
`herein.
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`the box stiffness relative to the pin stiffness, (2) optimize the preload generated
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`during the make-up process to minimize the local mean hydrostatic stress in the
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`coupling, and (3) decrease the severity of the stress concentrations which provide
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`preferred sites for fatigue damage. Ex. 1015, at 64-65. Each of these approaches
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`would be well-known to a POSITA in the industry prior to the filing of the ’951
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`Patent. The Hoffman Article also recognizes that “Any combination of the above
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`design approaches could be used to extend the service lives of existing sucker rod
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`couplings, or to design a coupling which would meet the desired requirement of
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`indefinite service life.” Ex. 1015, at 65. Further, the Hoffman article describes a
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`valuable analysis tool for design of sucker rod end fittings.
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`39. Thus, a POSITA at the time of the ’951 Patent’s filing would
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`understand the three factors described by the Hoffman Article are examples of the
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`motives for designing sucker rod end fittings. Many of the prior art end fitting
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`designs described herein discuss these same considerations. In particular, many of
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`the prior art discuss the third consideration from the Hoffman Article, designs that
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`help minimize “the severity of the stress concentrations which provide preferred
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`sites for fatigue damage.” Ex. 1015, at 65. Several more specific considerations
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`for designing wedge systems that were well-known at the time of the ’951 Patent
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`filin