Pharaoh Energy Services LLC v. Flex Chem Holding Co LLC

Prosecution History analysis

Examiner Search analysis

Invalidity Framework analysis

Petition

Petition Analysis

## 1. Case Identification
- Case #: [IPR2024-00815](https://ai-lab.exparte.com/case/ptab/IPR2024-00815)
- Patent #: [9,944,843](https://ai-lab.exparte.com/patent/9944843)
- Filed: April 17, 2024
- Petitioner(s): [Pharaoh Energy Services, LLC](https://ai-lab.exparte.com/party/pharaoh-energy-services-llc)
- Patent Owner(s): [Flex-Chem Holding Company, LLC](https://ai-lab.exparte.com/party/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 low-permeability (nano-darcy) shale formations. The methods involve injecting a treatment mixture containing a metal-complexing agent into an existing well at a pressure below the formation’s fracture pressure to bind and remove naturally occurring metals.

## 3. Grounds for Unpatentability

#### Ground 1: Claims 1, 2, 4, 5, 7, and 13 are anticipated under 35 U.S.C. §102 by Frenier.
- **Prior Art Relied Upon:** [Frenier](https://ai-lab.exparte.com/case/ptab/IPR2024-00815/doc/1004) (Patent 6,436,880).
- **Core Argument for this Ground:**
    - **Prior Art Mapping:** Petitioner argued that Frenier, which discloses acidic fluids for well stimulation, teaches every element of the challenged claims. Independent claim 1 recites a method for stimulating an *existing* well, and Petitioner asserted that Frenier’s disclosure of “workover operations” would be understood by a Person of Ordinary Skill in the Art (POSITA) to apply to existing wells. Frenier’s method involves treating low-permeability formations, which Petitioner contended a POSITA would understand to include nano-darcy shale.
    - Petitioner further mapped the limitations of claim 1 by arguing Frenier discloses: (1) a treatment mixture with a metal complexing agent (e.g., HEDTA, HEIDA, or acids) at concentrations and pH ranges that anticipate or render obvious the claimed ranges; (2) injecting the fluid using “matrix acidizing” methods, which are performed below fracture pressure and involve pumping the fluid out of the wellbore into the target formation; (3) maintaining the fluid in the formation via a “shut-in time” to allow it to react with and bind naturally present minerals like iron; and (4) subsequently removing the spent fluid to enhance well productivity, a step taught both directly and through multiple references incorporated by Frenier (e.g., [Grebe](https://ai-lab.exparte.com/case/ptab/IPR2024-00815/doc/1010), [Vandergrift](https://ai-lab.exparte.com/case/ptab/IPR2024-00815/doc/1011), [Kubala](https://ai-lab.exparte.com/case/ptab/IPR2024-00815/doc/1012)).
    - For dependent claims, Petitioner argued Frenier anticipates the use of specific agents, either directly or via incorporated references, including citric acid (claim 2), acetic acid (claim 4), and the Markush groups of chelating agents (claims 5 and 13).

#### Ground 2: Claims 1-13 are obvious 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](https://ai-lab.exparte.com/case/ptab/IPR2024-00815/doc/1005) (Patent 10,072,205).
- **Core Argument for this Ground:**
    - **Prior Art Mapping:** To the extent any claim is not anticipated by Frenier, Petitioner argued it is rendered obvious by Frenier, either alone or supplemented by Reyes. Petitioner contended Frenier alone makes the claimed ranges for concentration and pH obvious as routine optimization. Reyes provides additional, explicit teachings for the limitations of independent claim 1. Specifically, Reyes discloses acidizing treatments for subterranean formations, including treating an "existing fracture," using chelating agents like EDTA and citric acid at concentrations of 0.1% to 40%, and injecting fluids "below a fracture gradient pressure" so they "penetrate into [the] subterranean formation."
    - Reyes further discloses complexing with native minerals and flowing the treatment fluid back out of the well. The teachings of Reyes were also mapped to the dependent claims. For example, claim 6 recites various additives; both Frenier and Reyes disclose using corrosion inhibitors, biocides, mutual solvents, and surfactants. Reyes also explicitly discloses nearly identical Markush groups of chelating agents as recited in claims 5 and 13.
    - **Motivation to Combine (for §103 grounds):** A POSITA would combine Frenier and Reyes because they are analogous arts that address the same problem: improving the effectiveness of acid/chelating agent stimulation treatments while mitigating issues like precipitation damage. Both disclose using chelating agents (e.g., HEDTA) in acidizing operations. A POSITA would be motivated to combine their complementary approaches to achieve a more effective and comprehensive wellbore stimulation treatment.
    - **Expectation of Success (for §103 grounds):** Because the references share a common technological basis and use well-known, readily available components for wellbore treatments, a POSITA would have had a reasonable expectation of success in combining their teachings.

## 4. Arguments Regarding Discretionary Denial
- Petitioner argued that discretionary denial under §325(d) is unwarranted because the petition presents prior art and arguments not previously considered by the USPTO. While Frenier was listed on an Information Disclosure Statement (IDS) during prosecution, the Examiner never used it as the basis for a rejection.
- Petitioner contended the Examiner materially erred by failing to appreciate that Frenier taught the very limitations—specifically, treating an "existing" well and having the treatment mixture "exit[] the well"—that were added to the claims to overcome a rejection and secure allowance. Petitioner also introduced new evidence, including the expert declaration of [Dr. Harwell](https://ai-lab.exparte.com/case/ptab/IPR2024-00815/doc/1003), to support its contentions. The secondary reference, Reyes, was not before the Examiner at all.

## 5. Relief Requested
- Petitioner requests the institution of an inter partes review and the cancellation of claims 1-13 of the ’843 patent as unpatentable.

Shale well stimulation patent contested: All 13 claims face anticipation & obviousness challenges from Frenier & Reyes over matrix acidizing methods.