Flex Chem Holding Co LLC v. Pharaoh Energy Services LLC

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Flex-Chem Holding Company, LLC and Flex-Chem Services Corporation (Oklahoma)
  • Defendant: Pharaoh Energy Services, LLC (Oklahoma)
  • Plaintiff’s Counsel: Tomlinson McKinstry, P.C.; Merchant & Gould P.C.
• Case Identification: 5:23-cv-00316, W.D. Okla., 12/28/2023
• Venue Allegations: Venue is alleged to be proper in the Western District of Oklahoma because the Defendant is a resident of the district, has committed acts of infringement there, and maintains a regular and established place of business in the district.
• Core Dispute: Plaintiff alleges that Defendant’s well stimulation and remediation services infringe four patents related to chemical methods for improving hydrocarbon production from shale formations.
• Technical Context: The technology concerns chemical treatments used in the oil and gas industry to increase the productivity of wells, particularly those in low-permeability shale formations, a key sector of modern energy extraction.
• Key Procedural History: The complaint alleges that Plaintiff sent a notice letter identifying three of the asserted patents to the Defendant on or about February 10, 2023, which was received on February 14, 2023. A fourth patent, which issued later, was allegedly identified to the Defendant in a subsequent letter on November 14, 2023. These allegations of pre-suit and post-suit notice form the basis for the willfulness claims.

Case Timeline

Date	Event
2013-10-25	Earliest Priority Date ('282 Patent)
2014-04-14	Earliest Priority Date ('843, '575, '234 Patents)
2018-04-17	U.S. Patent No. 9,944,843 Issues
2020-04-28	U.S. Patent No. 10,633,575 Issues
2020-06-30	U.S. Patent No. 10,697,282 Issues
2023-02-10	Plaintiff allegedly learns of Defendant's scheduled jobs
2023-02-14	Defendant allegedly receives notice letter for '843, '575, '282 patents
2023-10-31	U.S. Patent No. 11,802,234 Issues
2023-11-14	Defendant allegedly receives notice of '234 patent
2023-12-28	Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 9,944,843 - "Stimulation Of Wells In Nano-Darcy Shale Formations," Issued April 17, 2018

The Invention Explained

• Problem Addressed: The patent describes that conventional well stimulation techniques are often ineffective or less effective in "nano-darcy shale formations," which are geological formations with extremely low fluid permeability (less than 1 micro-darcy) ('843 Patent, col. 1:17-20, 1:40-45).
• The Patented Solution: The invention proposes a method to stimulate these low-permeability wells by injecting a chemical "treatment mixture" containing a metal complexing agent (such as citric acid) at a pressure below the formation's fracture pressure ('843 Patent, Abstract). This mixture is designed to bind with naturally occurring metals within the shale, which are then removed when the fluid is pumped out, thereby increasing the formation's permeability and improving hydrocarbon production ('843 Patent, col. 2:30-37).
• Technical Importance: This method provides a non-fracturing chemical stimulation technique tailored to the specific challenges of nano-darcy shale, aiming to enhance recovery from wells that might otherwise be underproductive ('843 Patent, col. 1:40-45).

Key Claims at a Glance

• The complaint asserts independent claim 1 ('843 Patent, Compl. ¶21).
• The essential elements of independent claim 1 are:
  • Providing a treatment mixture with a metal complexing agent at a specific pH range.
  • Injecting the mixture into a well in a nano-darcy shale formation at a pressure less than its fracture pressure.
  • Maintaining the mixture in contact with the formation for a specified time to allow the agent to bind with naturally-occurring metals.
  • Removing the mixture from the well, thereby removing the bound metals and improving hydrocarbon production relative to the pre-treatment level.
• The complaint does not explicitly reserve the right to assert dependent claims.

U.S. Patent No. 10,633,575 - "Stimulation of Wells in Nano-Darcy Shale Formations," Issued April 28, 2020

The Invention Explained

• Problem Addressed: As a continuation of the application leading to the '843 patent, the '575 patent addresses the same problem of improving hydrocarbon recovery from low-permeability shale formations where traditional stimulation is less effective ('575 Patent, col. 1:40-45).
• The Patented Solution: The '575 patent describes a similar solution: using a treatment mixture with a metal complexing agent to bind with and remove naturally occurring metals from the shale formation, which is theorized to increase the rock's permeability and, consequently, hydrocarbon flow ('575 Patent, Abstract; col. 2:30-37). A key distinction is that the asserted claim in the '575 patent is directed to a "shale formation" generally, without the "nano-darcy" limitation present in the '843 patent's asserted claim ('575 Patent, col. 18:31-32).
• Technical Importance: This patent broadens the potential applicability of the chemical stimulation method to a wider range of shale formations, not just those meeting the technical definition of "nano-darcy" ('575 Patent, col. 18:31-32).

Key Claims at a Glance

• The complaint asserts independent claim 1 ('575 Patent, Compl. ¶29).
• The essential elements of independent claim 1 are:
  • Providing a treatment mixture with a metal complexing agent at a specific pH range.
  • Injecting the mixture into a well until it contacts the shale formation.
  • Maintaining the mixture in contact with the formation for a specified time to bind with naturally-occurring metals.
  • Removing the mixture, thereby removing the bound metals and improving hydrocarbon production.
• The complaint does not explicitly reserve the right to assert dependent claims.

U.S. Patent No. 11,802,234 - "Stimulation Of Wells In Nano-Darcy Shale Formations," Issued October 31, 2023

• Patent Identification: U.S. Patent No. 11,802,234, "Stimulation Of Wells In Nano-Darcy Shale Formations," Issued October 31, 2023 (Compl. ¶11).
• Technology Synopsis: As part of the same family as the '843 and '575 patents, the '234 patent also relates to methods for stimulating wells in shale formations. It describes providing a treatment mixture containing both a metal complexing agent (e.g., citric acid) and a separate acid as a pH modifier (e.g., hydrochloric acid) to remove naturally-occurring metals and improve production ('234 Patent, col. 2:58-64; claim 24).
• Asserted Claims: The complaint asserts at least independent claim 24 (Compl. ¶37).
• Accused Features: The accused feature is Defendant's well stimulation service, which allegedly provides a treatment mixture containing "about 5% citric acid and about 10% by weight of hydrochloric acid as pH modifier," matching the claimed components (Compl. ¶38.1).

U.S. Patent No. 10,697,282 - "Method for Remediation of Subterranean-Formed Metal-Polymer Complexes Using A Metal Complexing Agent," Issued June 30, 2020

• Patent Identification: U.S. Patent No. 10,697,282, "Method for Remediation of Subterranean-Formed Metal-Polymer Complexes Using A Metal Complexing Agent," Issued June 30, 2020 (Compl. ¶13).
• Technology Synopsis: This patent addresses a different but related problem: the remediation of "subterranean-formed metal-polymer complexes" ('282 Patent, Abstract). These complexes are described as forming when polymers from previously injected fracturing fluids cross-link with metals, creating blockages that reduce hydrocarbon flow ('282 Patent, col. 1:20-24; col. 2:35-41). The patented solution is a method to break these cross-links using a metal complexing agent, thereby dissolving the blockage.
• Asserted Claims: The complaint asserts at least independent claim 1 (Compl. ¶45).
• Accused Features: The accused feature is Defendant's well remediation service. The infringement theory is that this service remediates these specific metal-polymer complexes by injecting a remediation mixture that causes the complexes to "dissociate and dissolve" (Compl. ¶46.2, ¶46.3).

III. The Accused Instrumentality

• Product Identification: The accused instrumentalities are Defendant Pharaoh's "well stimulation and remediation services" (Compl. ¶21, ¶29, ¶37, ¶45).
• Functionality and Market Context:
  • The complaint alleges that Pharaoh performs a multi-step process for treating oil and gas wells (Compl. ¶16). This process involves providing a treatment mixture of approximately "10% hydrochloric acid and 5% citric acid" and injecting it into wells at a pressure below the shale formation's fracture pressure (Compl. ¶16). The mixture is allegedly maintained in contact with the formation for a period of time before being removed, with the alleged purpose of removing metals and improving hydrocarbon production (Compl. ¶16).
  • The complaint alleges these services are offered in direct competition with Plaintiff's own patented services, for the same customers in west-central Oklahoma, including in the STACK Area, suggesting a direct market overlap (Compl. ¶14, ¶15, ¶18, ¶21).
• Evidence: No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

U.S. Patent No. 9,944,843 Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
A method for stimulating an existing well in a nano-darcy shale formation comprising:	Defendant performs well stimulation services for wells in west-central Oklahoma, including in the STACK Area, which allegedly involves nano-darcy shale formations.	¶21, ¶22	col. 1:17-20
providing a treatment mixture containing between about 0.1% and 95% by weight metal complexing agent at a pH of between about 0 and 10	Defendant allegedly provides a treatment mixture containing "about 5% citric acid metal complexing agent at a pH of about 0 to 10." Citric acid is a species of metal complexing agent.	¶22.1	col. 5:48-49
injecting the treatment mixture into the well at a pressure less than a fracture pressure of the nano-darcy shale formation until at least some of the treatment mixture exits the well and contacts the nano-darcy shale formation	Defendant allegedly injects its treatment mixture into the well "at a pressure less than a fracture pressure of the nano-darcy shale formation" until it contacts the formation.	¶22.2	col. 2:18-22
maintaining the treatment mixture in contact with the nano-darcy shale formation for a contact time of between about 1 minute to 100 days, thereby allowing the metal complexing agent to bind with at least some naturally-occurring metals...	Defendant allegedly maintains its treatment mixture in contact with the formation for a contact time within the claimed range, allowing the agent to bind with naturally-occurring metals.	¶22.3	col. 9:11-15
removing the treatment mixture from the well after the contact time, thereby removing the bound naturally-occurring metals... and thereby improving the hydrocarbon production of the well...	Defendant allegedly removes the treatment mixture after the contact time, thereby removing the bound metals and improving hydrocarbon production.	¶22.4	col. 9:35-44

U.S. Patent No. 10,633,575 Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
A method for stimulating a well in a shale formation comprising:	Defendant performs well stimulation services in shale formations in west-central Oklahoma.	¶29, ¶30	col. 18:31-32
providing a treatment mixture containing between about 0.1% and 95% by weight metal complexing agent at a pH of between about 0 and 10	Defendant allegedly provides a treatment mixture containing "about 5% citric acid metal complexing agent at a pH of about 0 to 10."	¶30.1	col. 5:48-49
injecting the treatment mixture into the well until at least some of the treatment mixture contacts the shale formation	Defendant allegedly injects its treatment mixture into the well until it contacts the shale formation.	¶30.2	col. 2:43-46
maintaining the treatment mixture in contact with the shale formation for a contact time of between about 1 minute to 100 days, most likely less than 30 days, thereby allowing the metal complexing agent to bind with at least some naturally-occurring metals...	Defendant allegedly maintains its treatment mixture in contact with the formation for a contact time within the claimed range, allowing the agent to bind with naturally-occurring metals.	¶30.3	col. 9:11-15
removing the treatment mixture from the well after the contact time, thereby removing the bound naturally-occurring metals... and thereby improving hydrocarbon production of the well...	Defendant allegedly removes the treatment mixture after the contact time, thereby removing the bound metals and improving hydrocarbon production.	¶30.4	col. 9:35-44

Identified Points of Contention

• Scope Questions: A central question for the '843 and '234 patents will be whether the specific wells Defendant has treated are in fact "nano-darcy shale formations" as defined by the patents. While the '575 patent lacks this limitation in its asserted claim, making its scope facially broader, the Defendant may argue the invention is properly limited to the nano-darcy context disclosed throughout the specification.
• Technical Questions: The '282 patent is directed at remediating "subterranean-formed metal-polymer complexes" that result from prior fracturing fluids. In contrast, the '843 family of patents is directed at removing "naturally-occurring metals" from the shale itself. A key factual dispute may arise over what Pharaoh's process actually accomplishes: does it primarily break down man-made polymer complexes, remove naturally occurring metals, or both? The evidence of what is happening chemically downhole will be central to determining which, if any, patents are infringed.
• Evidentiary Questions: The claims require "improving the hydrocarbon production of the well relative to the hydrocarbon production immediately prior to" the treatment. This raises an evidentiary question of whether Plaintiff can establish, for each instance of alleged infringement, that this specific functional outcome was achieved.

V. Key Claim Terms for Construction

• Term: "nano-darcy shale formation" (from '843 Patent, Claim 1)

• Context and Importance: This term is the primary scope-defining limitation of asserted claim 1 of the '843 patent and distinguishes it from the broader claim 1 of the '575 patent. The infringement analysis for the '843 patent will depend on whether the specific shale formations treated by the Defendant meet this technical definition.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: A party could argue that the term should not be overly restrictive, as the core of the invention is the chemical treatment, and the patent describes its application in shale formations generally.
  • Evidence for a Narrower Interpretation: The patent provides an explicit definition, stating that "Nano-darcy shale formations refer to those shale formations having an average permeability in at least one direction of less than 1 micro-darcy" ('843 Patent, col. 1:17-20). This language provides a precise, limiting quantitative boundary that a court may adopt.

• Term: "subterranean-formed metal-polymer complex" (from '282 Patent, Claim 1)

• Context and Importance: This term is central to the '282 patent's infringement theory, which is distinct from the other asserted patents. It defines the specific target of the remediation method. Practitioners may focus on this term because the case may turn on whether the accused process is proven to remediate these specific complexes (formed from fracturing fluids) as opposed to simply removing naturally occurring metals from the rock matrix.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: A party might argue the term covers any polymer-and-metal combination found in the well that impedes flow, regardless of its precise formation mechanism.
  • Evidence for a Narrower Interpretation: The specification explicitly links the formation of these complexes to materials used in the fracturing process, stating they form when "polymers such as polyacrylamide... cross-link with metal ions" from fracturing fluids, creating "blockages" ('282 Patent, col. 2:35-41, col. 1:20-24). The claims further specify the complex "forms from a previously injected fracturing fluid" ('282 Patent, Claim 1), suggesting the term is limited to man-made, post-fracturing blockages.

VI. Other Allegations

• Indirect Infringement: The complaint alleges that Defendant directly infringed by "performing or causing the performance" of the claimed method steps (Compl. ¶22, ¶30, ¶38, ¶46). The "causing the performance" language suggests a theory of induced infringement, but the complaint does not plead specific facts detailing how Defendant would have induced a third party (such as a well operator) to perform any of the claimed steps.
• Willful Infringement: The complaint alleges that Defendant had pre-suit knowledge of the '843, '575, and '282 patents as of February 14, 2023, via a certified mail notice letter (Compl. ¶17, ¶23, ¶31, ¶47). It further alleges knowledge of the '234 patent as of November 14, 2023, via a letter from counsel sent after the patent issued (Compl. ¶39). The complaint alleges that Defendant's infringement continued after receiving these notices, forming the basis for the willfulness allegations for all four patents (Compl. ¶25, ¶33, ¶41, ¶49).

VII. Analyst’s Conclusion: Key Questions for the Case

The resolution of this case appears to hinge on several key technical and evidentiary questions for the court:

• A primary issue will be one of technical mechanism: what does the accused service actually do on a chemical level? Is it primarily removing naturally-occurring metals from the shale matrix (implicating the '843 patent family), or is it breaking down man-made metal-polymer complexes from prior fracturing operations (implicating the '282 patent), or both? The evidence on this point will be critical to determining liability under the distinct theories of the asserted patents.
• A second core issue will be one of definitional scope and proof: for the claims directed to a "nano-darcy shale formation," what evidence will be required to prove that the specific wells treated by the Defendant meet this precise technical threshold of permeability? This presents a significant factual and evidentiary hurdle for the Plaintiff.
• Finally, a key evidentiary question will be one of functional outcome: can the Plaintiff prove that the accused process meets the claim limitation of "improving hydrocarbon production" relative to the pre-treatment baseline for each accused act of infringement? This requires specific before-and-after evidence for each well treatment.