Arsenal Casing Equipment LLC v. Citadel Casing Solutions LLC

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Arsenal Casing Equipment, LLC (Texas)
  • Defendant: Citadel Casing Solutions, LLC (Texas)
  • Plaintiff’s Counsel: McCutcheon Joseph, PLLC
• Case Identification: 4:25-cv-01786, S.D. Tex., 04/17/2025
• Venue Allegations: Plaintiff alleges venue is proper in the Southern District of Texas because Defendant’s principal place of business is in the district and it has purposefully directed enforcement activities for the patent-in-suit into the district.
• Core Dispute: This is a declaratory judgment action in which Plaintiff seeks a judicial declaration that its "wet shoe technology" does not infringe Defendant's patent related to a downhole wellbore tool.
• Technical Context: The technology relates to "shoe track" assemblies used in the oil and gas industry for cementing well casings, a critical step in well construction.
• Key Procedural History: The complaint details a series of pre-suit communications, beginning with a September 2024 infringement allegation letter from Defendant, which Plaintiff alleges establishes a justiciable controversy for declaratory judgment. Plaintiff contends Defendant’s allegations are based on a misunderstanding of the accused technology, referencing an obsolete system and components not in use.

Case Timeline

Date	Event
2019-04-01	’966 Patent Priority Date
2024-09-17	’966 Patent Issue Date
2024-09-18	Defendant allegedly sends first infringement allegation letter to Plaintiff
2024-11-15	Defendant allegedly sends second infringement allegation letter to Plaintiff
2025-03-21	Defendant allegedly sends third infringement allegation letter to Plaintiff
2025-04-17	Complaint for Declaratory Judgment Filed

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

• Patent Identification: U.S. Patent No. 12,091,966, “Shoe Track Assembly System and Method of Use,” issued September 17, 2024.

The Invention Explained

• Problem Addressed: The patent’s background section describes conventional wellbore shoe track systems as being long, complex, and costly, often comprising numerous casing joints that can extend up to 160 feet. These systems traditionally rely on the structural integrity of surrounding cement to withstand high-pressure tests required during well operations (’966 Patent, col. 1:20-41).
• The Patented Solution: The invention is a single, compact tool, approximately five feet long, that integrates the necessary valves and plug landing seats into one housing (’966 Patent, col. 2:34-36). This tool is designed to receive a plug from the surface, creating a seal that allows for casing pressure testing without relying on the integrity of the shoe track cement, thereby increasing efficiency and reducing the number of components and potential points of failure (’966 Patent, col. 4:48-59).
• Technical Importance: The claimed invention aims to reduce the cost and complexity of well completion operations by replacing a long string of casing components with a single, integrated tool (’966 Patent, col. 1:45-49).

Key Claims at a Glance

• The complaint indicates Defendant asserted infringement of claims 1 and 5 (’966 Patent, Compl. ¶13).
• Independent Claim 1 (System):
  • An elongated housing
  • One or more valves inside the housing to seal the bottom end from formation fluid flow
  • One or more plug landing mechanisms positioned above the valves
  • A plug, dropped from the surface, that travels to and engages a landing mechanism to seal the top end of the housing
  • The system is configured for well operations independent of cement integrity
  • The plug and landing mechanism are separate entities from the valves
  • The plug travels from the surface to the landing mechanism without intermittent stopping
• Independent Claim 5 (Method):
  • Providing a tool with a housing and a plug landing mechanism
  • Positioning a first valve below the landing mechanism to seal against formation fluid flow, with the valve being a separate entity from the landing mechanism
  • Securing the tool to a well casing and running it into a wellbore
  • Performing well operations that do not establish cement integrity within the tool, such that the valve is not filled with cement
  • Wherein the valve independently prevents fluid flow without established cement integrity

III. The Accused Instrumentality

Product Identification

• Plaintiff’s “wet shoe technology,” also referred to as the “accused Arsenal System” (Compl. ¶10).

Functionality and Market Context

• The complaint describes the accused system as being "designed for conducting cementing operations and/or other well operations in a casing, within a wellbore, and preventing fluid flow into the casing after over displacing cement through the equipment" (Compl. ¶9). The complaint does not provide further technical detail on the specific components or operation of the accused system, but notes that Plaintiff is a "rapidly growing independent provider of casing solutions and drilling tools in the oil and gas sector" (Compl. ¶9).

IV. Analysis of Infringement Allegations

The complaint does not provide sufficient detail for analysis of its non-infringement position in a claim chart format. It makes a general assertion that its technology “does not satisfy each and every element of any of the claims of the ‘966 Patent” (Compl. ¶21). The central non-infringement theory appears to be a factual one: that the Defendant’s allegations are based on incorrect information about the accused product’s design.

No probative visual evidence provided in complaint.

• Identified Points of Contention:
  • Technical Questions: A primary factual dispute appears to be whether the accused Arsenal System uses a "plug" that is "dropped from a surface" to "seal the top end of the housing" as required by claim 1. The complaint alleges that Defendant's infringement contention is based on a photograph of a "wiper plug, which is not used in the Arsenal wet shoe technology" (Compl. ¶13). This raises the question of whether the accused system includes a component that performs the function of the claimed "plug" at all.
  • Scope Questions: Assuming the accused system has some form of flow-control device, the dispute may turn on whether that device meets the definition of a "plug" and interacts with a "plug landing mechanism" as those terms are defined by the claims. The patent requires the plug to be a separate entity that travels from the surface to land and seal within the tool (’966 Patent, col. 4:51-64). The case may question whether Arsenal’s system, if it lacks such a component, can fall within the scope of the claims.

V. Key Claim Terms for Construction

• The Term: "plug"
• Context and Importance: This term appears central to the dispute, as the complaint explicitly states that a "wiper plug... is not used in the Arsenal wet shoe technology" (Compl. ¶13), suggesting a fundamental mismatch between the claimed invention and the accused product. The definition of "plug" will therefore be critical to determining infringement of both the system claim (claim 1) and the method claim (claim 5).
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The specification refers generally to "one or more plugs to be dropped into the elongated housing" (’966 Patent, Abstract) and mentions "one or more wiper plugs" in the context of the operational method (’966 Patent, col. 4:13). A party could argue this supports a construction that encompasses various types of plugs known in the art.
  • Evidence for a Narrower Interpretation: Claim 1 requires the plug to perform specific functions: it must be "dropped from a surface," "travel into the elongated housing," "engage with a first landing mechanism," and "seal[] the top end of the elongated housing" (’966 Patent, col. 4:51-54). The specification shows a specific embodiment of a "top plug 404" that lands on a "top plug landing seat 401" to achieve this seal (’966 Patent, Fig. 5; col. 3:30-34). This may support a narrower construction limited to a component that performs this specific sealing function at the top of the tool, as distinct from other devices like bottom plugs or conventional wiper plugs that may not seal in the same manner.

VI. Other Allegations

• Indirect Infringement: Plaintiff seeks a declaration that it does not infringe "either directly or indirectly" (Compl. ¶1) and makes a conclusory statement that it "has not and does not induce or contribute to the alleged infringement" (Compl. ¶22). The complaint does not plead any specific facts regarding the basis for potential indirect infringement allegations.
• Willful Infringement: While not alleged by the Plaintiff, the complaint establishes a basis for a potential willfulness counterclaim by the Defendant. The complaint alleges that Defendant sent multiple letters to Plaintiff starting on September 18, 2024, providing pre-suit notice of alleged infringement (Compl. ¶¶11, 13, 15).

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

• A core issue will be one of factual correspondence: does Arsenal’s accused "wet shoe technology" actually contain a component that functions as the "plug" recited in the ’966 Patent's claims? The complaint’s assertion that Defendant’s infringement theory is based on a component that Arsenal does not use places this fundamental technical question at the heart of the litigation.
• The case will also likely involve a critical question of claim construction: how broadly or narrowly should the term "plug" be defined? The outcome may depend on whether the term is construed to cover any device that restricts flow, or if it is limited by the specification’s embodiments to a component that is dropped from the surface to create a pressure-tight seal at the top of the tool housing, independent of cement.