IPR2025-00066
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`U.S. Pat. No. 10,598,258
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`UNITED STATES PATENT AND TRADEMARK OFFICE
`____________
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`
`
`LIBERTY ENERGY, INC. AND LIBERTY OILFIELD SERVICES LLC,
`Petitioners,
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`v.
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`U.S. WELL SERVICES, LLC,
`Patent Owner.
`____________
`
`Case IPR2025-00066
`Patent No. 10,598,258
`____________
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`DECLARATION OF DR. ROBERT A. DURHAM
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`LIBERTY EXHIBIT 1003, Page 1
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`IPR2025-00066
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`U.S. Pat. No. 10,598,258
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`TABLE OF CONTENTS
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`INTRODUCTION & QUALIFICATIONS .....................................................14
`I.
`II. TASK SUMMARY AND MATERIALS REVIEWED ..................................20
`III. LIST OF EXHIBITS ........................................................................................20
`IV. SUMMARY OF CONCLUSIONS AND GROUNDS FOR CHALLENGE..25
`V. LEGAL STANDARDS ...................................................................................27
`A.
`Level of Ordinary Skill in the Art ..............................................................27
`B.
`Legal Standard for Claim Construction .....................................................28
`C. Anticipation ................................................................................................30
`D. Obviousness ...............................................................................................31
`E.
`Priority Date ...............................................................................................33
`VI. OVERVIEW OF THE CHALLENGED PATENT .........................................35
`A.
`The Subject Matter of the Challenged Patent ............................................36
`B.
`The Challenged Claims of the ’258 Patent ................................................39
`C.
`Prosecution History of the ’258 Patent ......................................................42
`D.
`Priority Date of the ’258 Patent .................................................................43
`VII. LEVEL OF ORDINARY SKILL IN THE ART .............................................43
`VIII. CLAIM CONSTRUCTION .............................................................................44
`IX. TECHNOLOGY BACKGROUND AND STATE OF THE ART ..................44
`A. History of Hydraulic Fracturing .................................................................44
`B.
`Types of Pumps – Fracturing Pump Chain ................................................48
`C.
`Pumping and Cavitation .............................................................................59
`D. Gearing Mechanisms ..................................................................................63
`E. Alternating Current (AC) systems .............................................................69
`F.
`Electric Motors ...........................................................................................72
`G. Adjustable Speed Drives / Variable Frequency Drives .............................73
`X. OVERVIEW OF THE PRIOR ART ...............................................................85
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`Buckley (Ex. 1004) .....................................................................................85
`A.
`Status of Buckley .....................................................................................85
`1.
`2. Overview of the Disclosure of Buckley and Buckley Provisional ..........86
`B.
`Bergan (Ex. 1006) ......................................................................................88
`1.
`Status of Bergan ......................................................................................88
`2. Overview of the Disclosure of Bergan ...................................................89
`C.
`Rosman (Ex. 1007) .....................................................................................89
`1.
`Status of Rosman ....................................................................................89
`2. Overview of the Disclosure of Rosman ..................................................90
`D.
`Payne (Ex. 1008) ........................................................................................90
`1.
`Status of Payne .......................................................................................90
`2. Overview of the Disclosure of Payne .....................................................90
`E.
`Yi (Ex. 1009) .............................................................................................91
`1.
`Status of Yi ..............................................................................................91
`2. Overview of the Disclosure of Yi............................................................91
`Jelaksa (Ex. 1012) .....................................................................................92
`Status of Jelaska .....................................................................................92
`1.
`2. Overview of the Disclosure of Jelaska ...................................................92
`G.
`Tutterow (Ex. 1013) ..................................................................................93
`1.
`Status of Tutterow ...................................................................................93
`2. Overview of the Disclosure of Tutterow ................................................93
`H. Nesbitt (Ex. 1014) .....................................................................................93
`1.
`Status of Nesbitt ......................................................................................93
`2. Overview of the Disclosure of Nesbitt ...................................................94
`XI. GROUND 1A: OBVIOUS OVER BUCKLEY and BERGAN IN VIEW OF the
`Knowledge of a POSITA and, in the alternative, Jelaska .......................................94
`A. Motivation to Combine ..............................................................................94
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`F.
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`Buckley and Bergan ................................................................................94
`1.
`Buckley, Bergan, and Jelaska ...............................................................103
`2.
`Independent Claim 1 ................................................................................104
`B.
`1[p]: “1. A hydraulic fracturing system for fracturing a subterranean
`1.
`formation comprising:” ..................................................................................105
`1[a]: “a multi-plunger hydraulic fracturing pump fluidly connected to a
`2.
`well associated with the subterranean formation, the multi-plunger pump
`configured to pump fluid into a wellbore associated with the well at a high
`pressure so that the fluid passes from the wellbore into the subterranean
`formation and fractures the subterranean formation;” ...................................106
`1[b]: “a plurality of motors positioned to simultaneously power the
`3.
`multi-plunger pump; and” ..............................................................................110
`1[c]: “a planetary gear train having a plurality of input pinion gears in
`4.
`rotational contact with each of the plurality of motors, .................................114
`1[d]: “wherein a gear ratio of the planetary gear train and a speed at
`5.
`which the plurality of motors operates are selected so as to limit a maximum
`pump speed associated with the multi-plunger pump.” .................................122
`C. Dependent Claim 3: “3. The system of claim 1, wherein the plurality of
`motors comprises one of a plurality of electric motors or a plurality of hydraulic
`motors.” ..............................................................................................................123
`D. Dependent Claim 6: “6. The system of claim 1, wherein the multi-plunger
`hydraulic fracturing pump comprises an odd number of plungers greater than or
`equal to five plungers.” ......................................................................................125
`XII. Ground 1B: OBVIOUS OVER YI and BERGAN IN VIEW OF the
`Knowledge of a POSITA and, in the alternative, Jelaska .....................................128
`A. Motivation to Combine ............................................................................128
`1. Yi and Bergan .......................................................................................128
`2. Yi, Bergan, and Jelaska ........................................................................137
`B.
`Independent Claim 1 ................................................................................138
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`1[p]: “A hydraulic fracturing system for fracturing a subterranean
`1.
`formation comprising:” ..................................................................................138
`1[a]: “a multi-plunger hydraulic fracturing pump fluidly connected to a
`2.
`well associated with the subterranean formation, the multi-plunger pump
`configured to pump fluid into a wellbore associated with the well at a high
`pressure so that the fluid passes from the wellbore into the subterranean
`formation and fractures the subterranean formation;” ...................................140
`1[b]: “a plurality of motors positioned to simultaneously power the
`3.
`multi-plunger pump; and” ..............................................................................144
`1[c]: “a planetary gear train having a plurality of input pinion gears in
`4.
`rotational contact with each of the plurality of motors,” ...............................147
`1[d]: “wherein a gear ratio of the planetary gear train and a speed at
`5.
`which the plurality of motors operates are selected so as to limit a maximum
`pump speed associated with the multi-plunger pump.” .................................153
`C. Dependent Claim 3: “3. The system of claim 1, wherein the plurality of
`motors comprises one of a plurality of electric motors or a plurality of hydraulic
`motors.” ..............................................................................................................154
`D. Dependent Claim 6: “6. The system of claim 1, wherein the multi-plunger
`hydraulic fracturing pump comprises an odd number of plungers greater than or
`equal to five plungers.” ......................................................................................157
`XIII. Ground 2A: OBVIOUS OVER BUCKLEY IN VIEW OF BERGAN
`FURTHER IN VIEW OF the Knowledge of a POSITA and, in the alternative,
`Jelaska and Tutterow .............................................................................................159
`A. Motivation to Combine ............................................................................159
`B. Dependent Claim 4: “4. The system of claim 1, wherein the maximum
`pump speed correlates to a critical plunger speed associated with the multi-
`plunger hydraulic fracturing pump.” .................................................................161
`C. Dependent Claim 5: “5. The system of claim 1, wherein the maximum
`pump speed is 5% or less over a critical plunger speed associated with the multi-
`plunger hydraulic fracturing pump.” .................................................................163
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`XIV. Ground 2B: Obvious over Yi IN VIEW OF BERGAN FURTHER IN
`VIEW OF the Knowledge of a POSITA and, in the alternative, Jelaska and
`Tutterow .................................................................................................................166
`A. Motivation to Combine ............................................................................166
`B. Dependent Claim 4: “4. The system of claim 1, wherein the maximum
`pump speed correlates to a critical plunger speed associated with the multi-
`plunger hydraulic fracturing pump.” .................................................................168
`C. Dependent Claim 5: “5. The system of claim 1, wherein the maximum
`pump speed is 5% or less over a critical plunger speed associated with the multi-
`plunger hydraulic fracturing pump.” .................................................................170
`XV. Ground 3A: OBVIOUS OVER BUCKLEY IN VIEW OF BERGAN
`FURTHER IN VIEW OF the Knowledge of a POSITA and, in the alternative,
`Jelaska and Nesbitt .................................................................................................172
`A. Motivation to Combine ............................................................................172
`B. Dependent Claim 7: “7. The system of claim 6, wherein a stroke length of
`each of the plungers associated with the multi-plunger hydraulic fracturing
`pump is selected to inversely relate to a pump speed associated with the multi-
`plunger hydraulic fracturing pump so as to achieve a predetermined flow rate.”
`
`174
`Independent Claim 15 ..............................................................................176
`C.
`15[p]: “15. A method for pumping fluid into a wellbore associated with
`1.
`a subterranean formation, the method comprising:” ......................................177
`15[a]: “fluidly connecting a multi-plunger hydraulic fracturing pump to
`2.
`a well associated with the subterranean formation such that the multi-plunger
`pump pumps fluid into the wellbore at a high pressure so that fluid passes
`from the wellbore into the subterranean formation and fractures the
`subterranean formation;” ...............................................................................178
`15[b]: “simultaneously powering the multi-plunger pump with a
`3.
`plurality of motors;” .......................................................................................178
`15[c]: “providing a planetary gear train having a plurality of input
`4.
`pinion gears in rotational contact with each of the plurality of motors so as to
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`translate power from the plurality of motors into a desired pump rate of the
`multi-plunger pump.” .....................................................................................179
`D. Dependent Claim 17: “The method of claim 15, wherein the plurality of
`motors comprises one of a plurality of electric motors or a plurality of hydraulic
`motors.” ..............................................................................................................180
`XVI. Ground 3B: Obvious over Yi IN VIEW OF BERGAN FURTHER IN
`VIEW OF the Knowledge of a POSITA and, in the alternative, Jelaska and Nesbitt
`
`180
`A. Motivation to Combine ............................................................................180
`B. Dependent Claim 7: “7. The system of claim 6, wherein a stroke length of
`each of the plungers associated with the multi-plunger hydraulic fracturing
`pump is selected to inversely relate to a pump speed associated with the multi-
`plunger hydraulic fracturing pump so as to achieve a predetermined flow rate.”
`
`182
`Independent Claim 15 ..............................................................................185
`C.
`15[p]: “A method for pumping fluid into a wellbore associated with a
`5.
`subterranean formation, the method comprising:” ........................................185
`15[a]: “fluidly connecting a multi-plunger hydraulic fracturing pump to
`6.
`a well associated with the subterranean formation such that the multi-plunger
`pump pumps fluid into the wellbore at a high pressure so that fluid passes
`from the wellbore into the subterranean formation and fractures the
`subterranean formation;” ...............................................................................186
`15[b]: “simultaneously powering the multi-plunger pump with a
`7.
`plurality of motors;” .......................................................................................187
`15[c]: “providing a planetary gear train having a plurality of input
`8.
`pinion gears in rotational contact with each of the plurality of motors so as to
`translate power from the plurality of motors into a desired pump rate of the
`multi-plunger pump.” .....................................................................................187
`D. Dependent Claim 17: “17. The method of claim 15, wherein the plurality
`of motors comprises one of a plurality of electric motors or a plurality of
`hydraulic motors.” ..............................................................................................188
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`XVII. GROUND 4A: OBVIOUS OVER BUCKLEY IN VIEW OF BERGAN
`FURTHER IN VIEW OF ROSMAN and the Knowledge of a POSITA and, in the
`alternative, Jelaska and nesbigtt ............................................................................189
`A. Motivation to Combine ............................................................................189
`B. Dependent Claim 2: “2. The system of claim 1, the system further
`comprising a plurality of speed reduction gearboxes positioned between the
`plurality of input pinion gears and the plurality of motors so as to achieve a
`desired pump rate.” ............................................................................................197
`C. Dependent Claim 16: “The method of claim 15, further comprising:
`positioning a plurality of speed reduction gearboxes between the plurality of
`input pinion gears and the plurality of motors so as to achieve the desired pump
`rate.” 201
`XVIII. GROUND 4B: OBVIOUS OVER Yi IN VIEW OF BERGAN
`FURTHER IN VIEW OF ROSMAN and the Knowledge of a POSITA and, in the
`alternative, Jelaska and nesbitt ..............................................................................201
`A. Motivation to Combine ............................................................................201
`B. Dependent Claim 2: “The system of claim 1, the system further
`comprising a plurality of speed reduction gearboxes positioned between the
`plurality of input pinion gears and the plurality of motors so as to achieve a
`desired pump rate.” ............................................................................................205
`C. Dependent Claim 16: “The method of claim 15, further comprising:
`positioning a plurality of speed reduction gearboxes between the plurality of
`input pinion gears and the plurality of motors so as to achieve the desired pump
`rate.” 208
`XIX. GROUND 5A: OBVIOUS OVER BUCKLEY IN VIEW OF BERGAN
`FURTHER IN VIEW OF PAYNE and the Knowledge of a POSITA and, in the
`alternative, Jelaska .................................................................................................209
`A. Motivation to Combine ............................................................................209
`B. Dependent Claim 8: “8.The system of claim 1, further comprising: a
`variable frequency drive (VFD) connected to the plurality of motors to control
`the speed of the plurality of motors, wherein the VFD is positioned to accelerate
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`or decelerate pump rotational speeds associated with the multi-plunger hydraulic
`fracturing pump.” ...............................................................................................214
`C. Dependent Claim 9: “9. The system of claim 8, wherein the VFD
`comprises a plurality of VFDs and wherein the plurality of VFDs are configured
`to share a load required to power the multi-plunger hydraulic fracturing pump.”
`
`216
`D. Dependent Claim 10: “10. The system of claim 9, wherein the plurality of
`VFDs are configured to automatically shut off in the event of an overpressure
`event with respect to the multi-plunger hydraulic fracturing pump.” ...............217
`E.
`Independent Claim 11: .............................................................................219
`1.
`11[p]: “11. A hydraulic fracturing system for fracturing a subterranean
`formation comprising:” ..................................................................................219
`11[a]: “a multi-plunger hydraulic fracturing pump fluidly connected to a
`2.
`well associated with the subterranean formation, the multi-plunger pump
`configured to pump fluid into a wellbore associated with the well at a high
`pressure so that the fluid passes from the wellbore into the subterranean
`formation and fractures the subterranean formation;” ...................................219
`11[b]: “a plurality of motors positioned to simultaneously power the
`3.
`multi-plunger pump;” .....................................................................................220
`11[c]: “a variable frequency drive connected to the plurality of motors to
`4.
`control the speeds of the plurality of motors; and” ........................................220
`11[d]: “a planetary gear train having a plurality of input pinion gears in
`5.
`rotational contact with each of the plurality of motors, “ ..............................220
`11[e]: “wherein a gear ratio of the planetary gear train and a speed at
`6.
`which the plurality of motors operates are selected so as to limit a maximum
`pump speed associated with the multi-plunger pump.” .................................220
`Dependent Claim 13: “The system of claim 11, wherein the plurality of
`F.
`motors comprises one of a plurality of electric motors or a plurality of hydraulic
`motors.” ..............................................................................................................221
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`XX. GROUND 5B: OBVIOUS OVER Yi IN VIEW OF BERGAN FURTHER IN
`VIEW OF PAYNE and the Knowledge of a POSITA and, in the alternative, Jelaska
`
`221
`A. Motivation to Combine ............................................................................221
`B. Dependent Claim 8: “8.The system of claim 1, further comprising: a
`variable frequency drive (VFD) connected to the plurality of motors to control
`the speed of the plurality of motors, wherein the VFD is positioned to accelerate
`or decelerate pump rotatioal speeds associated with the multi-plunger hydraulic
`fracturing pump.” ...............................................................................................226
`C. Dependent Claim 9: “9. The system of claim 8, wherein the VFD
`comprises a plurality of VFDs and wherein the plurality of VFDs are configured
`to share a load required to power the multi-plunger hydraulic fracturing pump.”
`
`228
`D. Dependent Claim 10: “10. The system of claim 9, wherein the plurality of
`VFDs are configured to automatically shut off in the event of an overpressure
`event with respect to the multi-plunger hydraulic fracturing pump.” ...............229
`E.
`Independent Claim 11: .............................................................................231
`7.
`11[p]: “11. A hydraulic fracturing system for fracturing a subterranean
`formation comprising:” ..................................................................................231
`11[a]: “a multi-plunger hydraulic fracturing pump fluidly connected to a
`8.
`well associated with the subterranean formation, the multi-plunger pump
`configured to pump fluid into a wellbore associated with the well at a high
`pressure so that the fluid passes from the wellbore into the subterranean
`formation and fractures the subterranean formation;” ...................................231
`11[b]: “a plurality of motors positioned to simultaneously power the
`9.
`multi-plunger pump;” .....................................................................................232
`10. 11[c]: “a variable frequency drive connected to the plurality of motors to
`control the speeds of the plurality of motors; and” ........................................232
`11. 11[d]: “a planetary gear train having a plurality of input pinion gears in
`rotational contact with each of the plurality of motors, “ ..............................232
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`12. 11[e]: “wherein a gear ratio of the planetary gear train and a speed at
`which the plurality of motors operates are selected so as to limit a maximum
`pump speed associated with the multi-plunger pump.” .................................232
`Dependent Claim 13: “The system of claim 11, wherein the plurality of
`F.
`motors comprises one of a plurality of electric motors or a plurality of hydraulic
`motors.” ..............................................................................................................233
`XXI. GROUND 6A: OBVIOUS OVER BUCKLEY IN VIEW OF BERGAN,
`Rosman, and Payne and further in view of the Knowledge of a POSITA and, in the
`alternative, Jelaska and Nesbitt ..............................................................................233
`A. Motivation to Combine ............................................................................233
`B. Dependent Claim 12: “12. The system of claim 11, the system further
`comprising a plurality of speed reduction gearboxes positioned between the
`plurality of input pinion gears and the plurality of motors so as to achieve a
`desired pump rate.” ............................................................................................234
`XXII. GROUND 6B: OBVIOUS OVER Yi IN VIEW OF BERGAN, Rosman,
`and Payne and further in view of the Knowledge of a POSITA and, in the
`alternative, Jelaska and Nesbitt ..............................................................................234
`A. Motivation to Combine ............................................................................234
`B. Dependent Claim 12: “12. The system of claim 11, the system further
`comprising a plurality of speed reduction gearboxes positioned between the
`plurality of input pinion gears and the plurality of motors so as to achieve a
`desired pump rate.” ............................................................................................235
`XXIII. Ground 7A: OBVIOUS OVER BUCKLEY IN VIEW OF BERGAN and
`Payne and further in view of the Knowledge of a POSITA and, in the alternative,
`Jelaska and Tutterow .............................................................................................236
`A. Motivation to Combine ............................................................................236
`B. Dependent Claim 14: “14. The system of claim 11, wherein the maximum
`pump speed correlates to a critical plunger speed associated with the multi-
`plunger hydraulic fracturing pump.” .................................................................236
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`XXIV. Ground 7B: OBVIOUS OVER Yi IN VIEW OF BERGAN and Payne
`and further in view of the Knowledge of a POSITA and, in the alternative, Jelaska
`and Tutterow ..........................................................................................................237
`A. Dependent Claim 14: “14. The system of claim 11, wherein the maximum
`pump speed correlates to a critical plunger speed associated with the multi-
`plunger hydraulic fracturing pump.” .................................................................237
`XXV. Ground 8A: OBVIOUS OVER BUCKLEY IN VIEW OF BERGAN and
`further in view of the Knowledge of a POSITA and, in the alternative, Jelaska,
`Tutterow, and Nesbitt .............................................................................................238
`A. Motivation to Combine ............................................................................238
`B. Dependent Claim 18: “The method of claim 15, wherein the maximum
`pump speed correlates to a critical plunger speed associated with the multi-
`plunger hydraulic fracturing pump.” .................................................................238
`XXVI. Ground 8B: OBVIOUS OVER Yi IN VIEW OF BERGAN and further
`in view of the Knowledge of a POSITA and, in the alternative, Jelaska, Tutterow,
`and Nesbitt ..............................................................................................................239
`A. Motivation to Combine ............................................................................239
`B. Dependent Claim 18: “18. The method of claim 15, wherein the maximum
`pump speed correlates to a critical plunger speed associated with the multi-
`plunger hydraulic fracturing pump.” .................................................................240
`XXVII. Ground 9A: OBVIOUS OVER BUCKLEY IN VIEW OF BERGAN and
`Payne and further in view of the Knowledge of a POSITA and, in the alternative,
`Jelaska and Nesbitt .................................................................................................240
`A. Motivation to Combine ............................................................................240
`B. Dependent Claim 19: “19. The method of claim 15, further comprising:
`connecting a variable frequency drive (VFD) to the plurality of motors so as to
`control the speed of the plurality of motors, wherein the VFD is positioned to
`accelerate or decelerate pump rotational speeds associated with the multi-
`plunger hydraulic fracturing pump” ..................................................................241
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`C. Dependent Claim 20: “20. The method of claim 19, the method further
`comprising: detecting an overpressure event with respect to the multi-plunger
`hydraulic fracturing pump; and automatically shutting off the VFD.” .............241
`XXVIII. Ground 9B: OBVIOUS OVER Yi IN VIEW OF BERGAN and Payne
`and further in view of the Knowledge of a POSITA and, in the alternative, Jelaska
`and Nesbitt ..............................................................................................................242
`A. Motivation to Combine ............................................................................242
`B. Dependent Claim 19: “19. The method of claim 15, further comprising:
`connecting a variable frequency drive (VFD) to the plurality of motors so as to
`control the speed of the plurality of motors, wherein the VFD is positioned to
`accelerate or decelerate pump rotational speeds associated with the multi-
`plunger hydraulic fracturing pump” ..................................................................242
`C. Dependent Claim 20: “20. The method of claim 19, the method further
`comprising: detecting an overpressure event with respect to the multi-plunger
`hydraulic fracturing pump; and automatically shutting off the VFD.” .............243
`XXIX.
`SECONDARY CONSIDERATIONS ..................................................243
`XXX. CONCLUSION ........................................................................................244
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`I, Robert A Durham, hereby declare as follows:
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`
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`I.
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`INTRODUCTION & QUALIFICATIONS
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`U.S. Pat. No. 10,598,258
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`1. My name is Dr. Robert A. Durham. I make this declaration based upon
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`my own personal knowledge and, if called upon to testify, would testify competently
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`to the matters contained herein.
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`2.
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`I have been asked to provide technical assistance in the inter partes
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`review of U.S. Patent No. 10,598,258, which I may abbreviate as “the ’258 Patent”
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`or refer to as the “Challenged Patent.” This declaration is a statement of my opinions
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`on issues related to the unpatentability of claims of the ’258 Patent. I am being
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`compensated at my normal hourly rate for my analysis, plus reimbursement for
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`expenses. My compensation does not depend on the content of my opinions or the
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`outcome of this proceeding.
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`3.
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`In formulating my opinions, I have relied upon my knowledge, training,
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`and experience in the relevant art. My qualifications are stated more fully in my
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`curriculum vitae, which has been provided as Appendix A. My CV also lists
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`publications on which I am a named author and identifies parties on behalf of whom
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`I have previously provided expert testimony within the past four years. Here, I
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`provide a brief summary of my qualifications.
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`4.
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`I am a consulting engineer with experience in a number of technical
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`areas. I have expertise in the oil and gas industry from drilling and completion to
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`14
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`LIBERTY EXHIBIT 1003, Page 14
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`IPR2025-00066
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`downstream. I have been working with oil field production companies, refining and
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`U.S. Pat. No. 10,598,258
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`chemical plants and e