PhaRaoh Energy Services LLC v. Flex Chem Holding Co LLC

1. Case Identification

• Case #: IPR2024-00815
• Patent #: 9,944,843
• Filed: April 17, 2024
• Petitioner(s): Pharaoh Energy Services, LLC
• Patent Owner(s): Flex-Chem Holding Co, LLC
• Challenged Claims: 1-13

2. Patent Overview

• Title: Stimulation of Wells in Nano-Darcy Shale Formations
• Brief Description: The ’843 patent describes methods for stimulating hydrocarbon production from wells in nano-darcy shale formations. The method involves injecting a treatment mixture containing a metal complexing agent at a specific pH and pressure, allowing it to contact the formation, and then removing the mixture to improve production.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1, 2, 4, 5, 7, and 13 under 35 U.S.C. §102 by Frenier

• Prior Art Relied Upon: Frenier (Patent 6,436,880).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Frenier disclosed every limitation of independent claim 1 and the challenged dependent claims. For claim 1, Petitioner asserted Frenier taught a method for stimulating existing hydrocarbon wells by disclosing its invention's use in "stimulation and workover operations." Frenier allegedly disclosed the claimed treatment mixture by teaching a fluid with a metal complexing agent (e.g., HEDTA) within the claimed concentration range of 0.1-95% by weight (disclosing 1-30%) and pH range of 0-10 (disclosing 1-12, preferably 1-4). The injection step was met by Frenier’s disclosure of "matrix acidizing," which involves pumping a composition into a target formation at a pressure below rock stress, causing the fluid to exit the wellbore. Petitioner contended that Frenier disclosed the "maintaining contact" step by teaching a "shut-in" period to allow for complete reaction, with examples of 24 and 72 hours falling within the claimed range of 1 minute to 100 days. Finally, Petitioner argued that Frenier and its incorporated references explicitly taught removing the spent acid after treatment to enhance well productivity, thereby disclosing the final removal step. For dependent claims, Frenier allegedly disclosed specific metal complexing agents like citric acid and acetic acid through its own text and incorporated references.

Ground 2: Obviousness of Claims 1-13 under 35 U.S.C. §103 over Frenier alone and/or in combination with Reyes

• Prior Art Relied Upon: Frenier (Patent 6,436,880) and Reyes (Patent 10,072,205).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that to the extent Frenier did not anticipate the claims, the claims were rendered obvious by Frenier, either alone or combined with Reyes. Both references address stimulating subterranean formations using treatment fluids containing chelating agents. Petitioner asserted that routine optimization of Frenier’s disclosed parameters would lead a person of ordinary skill in the art (POSITA) to the claimed ranges for concentration, pH, and contact time. Reyes allegedly provided further explicit teachings that reinforced Frenier’s disclosures. For example, Reyes taught using treatment fluids with chelating agents at concentrations of 0.1% to 40% and using established pH ranges to complex metal ions. Reyes also explicitly taught introducing fluids "below a fracture gradient pressure" and that the fluid may "penetrate into subterranean formation," directly mapping to the injection limitation of claim 1. For dependent claims requiring various additives (e.g., claims 6, 8, 9), Petitioner argued both Frenier and Reyes taught the use of such common additives (corrosion inhibitors, biocides, diverting agents), making their inclusion a matter of routine practice for a POSITA.
  • Motivation to Combine: Petitioner asserted a POSITA would combine Frenier and Reyes because they are analogous art addressing the same problem: improving hydrocarbon production while mitigating issues like precipitation damage. Both propose using acids and chelating agents. A POSITA would have been motivated to combine their complementary teachings to create a more effective and comprehensive wellbore stimulation treatment. For example, a POSITA would look to Reyes's explicit teachings on biodegradable chelating agents to improve upon the methods taught in Frenier.
  • Expectation of Success: A POSITA would have had a reasonable expectation of success in combining the references. The combination involved using well-understood, readily available wellbore treatment components and known principles of matrix acidizing. The shared technological foundation and predictable nature of the chemical agents would ensure the combined method would function as expected to improve hydrocarbon production.

4. Arguments Regarding Discretionary Denial

• Petitioner argued against discretionary denial under 35 U.S.C. §325(d), asserting that the petition presented art and arguments not previously considered by the USPTO. Petitioner contended that Reyes was never considered during the prosecution of the ’843 patent. Furthermore, while Frenier was listed on an Information Disclosure Statement (IDS), it was never used as the basis for a rejection. Petitioner argued the Examiner materially erred by failing to appreciate that Frenier explicitly disclosed the two key limitations—treating an "existing" well and having the treatment mixture "exit the well"—that were added to the claims to overcome prior art and secure allowance. Petitioner supported this argument with an expert declaration not available to the Examiner during prosecution.

5. Relief Requested

• Petitioner requested the institution of an inter partes review and the cancellation of claims 1-13 of Patent 9,944,843 as unpatentable.