C&M Oilfield Rentals v. Ensign Drilling: Oilfield Lighting IP Dispute Ends in Dismissal With Prejudice
C&M Oilfield Rentals, LLC brought a patent infringement action against Ensign US Southern Drilling, LLC and its parent Ensign Energy Services, Inc. over two patents covering oilfield lighting systems. After 771 days of litigation in the Texas Southern District Court, both parties filed a joint stipulated motion to dismiss with prejudice, terminating the case on May 3, 2024.
Two-Patent Oilfield Lighting Dispute Resolved by Joint Dismissal After Two Years
Filed on March 24, 2022 in the Southern District of Texas, this infringement action pitted C&M Oilfield Rentals, LLC against Ensign US Southern Drilling, LLC and its affiliate Ensign Energy Services, Inc. C&M asserted two United States patents — US10976016B2 (application no. US17/016083) and US10900626B2 (application no. US16/571527) — both directed to oilfield lighting systems, against Ensign’s commercial lighting system used in drilling operations.
The case concluded on May 3, 2024, when Judge Andrew S. Hanen signed an Order of Dismissal granting the parties’ Joint Stipulated Motion to Dismiss With Prejudice. A dismissal with prejudice is a final adjudication on the merits under applicable procedural rules, meaning C&M is permanently barred from re-asserting the same claims against Ensign based on the same patents and conduct. The joint nature of the stipulation indicates both sides agreed to the dismissal, strongly suggesting a negotiated resolution — likely a settlement or licensing arrangement — was reached, though specific terms remain confidential.
The 771-day duration before dismissal suggests the parties engaged in meaningful pre-trial activity — potentially including discovery, claim construction briefing, or licensing negotiations — before reaching agreement. The public record does not disclose any financial settlement terms, royalty arrangements, or licensing grants. The with-prejudice designation is significant: it forecloses any future litigation by C&M on these patents against Ensign for the same accused conduct, giving Ensign a durable resolution.
Filing to Dismissed with Prejudice in 771 days
771 days from filing to dismissal — above median for patent cases in S.D. Texas
Dismissed with prejudice: what the joint stipulation means for both parties
Joint stipulated dismissal with prejudice is a full and final termination
A dismissal with prejudice operates as a final judgment on the merits. Because both parties jointly stipulated to it, the court treats it as a mutual, binding resolution. C&M Oilfield Rentals cannot re-file suit against Ensign on US10976016B2 or US10900626B2 for the same accused conduct. The joint nature of the motion distinguishes this from a unilateral withdrawal and is consistent with a negotiated agreement between the parties.
Permanent bar on re-litigationC&M surrenders future infringement claims against Ensign on these patents
By agreeing to a with-prejudice dismissal, C&M Oilfield Rentals gives up any right to revive these specific infringement claims against Ensign. However, the joint stipulation suggests C&M likely extracted some form of consideration — a lump-sum payment, licensing fee, or operational undertaking — before agreeing to close the case permanently. The public record does not confirm any such terms; the inference derives from standard litigation settlement practice.
Claims resolved, terms undisclosedEnsign secures permanent peace on C&M’s oilfield lighting patent claims
The with-prejudice outcome gives Ensign US Southern Drilling and Ensign Energy Services durable certainty: C&M cannot reassert US10976016B2 or US10900626B2 against the same accused lighting system conduct. Any agreed terms — whether a paid-up licence, a design-around commitment, or a one-time payment — remain private. Ensign retains exposure to third-party patent holders in the oilfield lighting space and to future C&M claims on different patents or different accused products.
Protected against re-filing on these patentsConfidential resolution leaves broader market without public claim scope guidance
Because the case closed without a claim construction ruling or invalidity finding, the scope and validity of US10976016B2 and US10900626B2 remain judicially untested. Other oilfield equipment operators and lighting system suppliers cannot rely on this dismissal to assess their own exposure to these patents. C&M retains the right to assert both patents against other parties, and the lack of a public merits decision may encourage further enforcement activity in the oilfield lighting sector.
Patents remain enforceable against othersFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | C&M Oilfield Rentals, LLC | Company | Oilfield equipment rental company — holder of US10976016B2 and US10900626B2Search in Eureka ↗ |
| Defendant | Ensign US Southern Drilling, LLC | Company | Oilfield drilling operator and its Canadian parent; accused of infringing patented lighting systemsSearch in Eureka ↗ |
| Co-Defendant | Ensign Energy Services, Inc. | Company | Search in Eureka ↗ |
| Plaintiff counsel | Elizabeth Mooar Chiaviello | Attorney | Counsel for C&M Oilfield Rentals, LLCSearch in Eureka ↗ |
| Plaintiff counsel | Eugene S. Hwangbo | Attorney | Counsel for C&M Oilfield Rentals, LLCSearch in Eureka ↗ |
| Plaintiff counsel | Jason C. White | Attorney | Counsel for C&M Oilfield Rentals, LLCSearch in Eureka ↗ |
| Plaintiff counsel | Karon N. Fowler | Attorney | Counsel for C&M Oilfield Rentals, LLCSearch in Eureka ↗ |
| Plaintiff counsel | Susan Stradley | Attorney | Counsel for C&M Oilfield Rentals, LLCSearch in Eureka ↗ |
| Plaintiff law firm | Morgan, Lewis & Bockius, LLP | Law Firm | Representing C&M Oilfield Rentals, LLCSearch in Eureka ↗ |
| Defendant counsel | Gregory Lawrence Porter | Attorney | Counsel for Ensign US Southern Drilling, LLCSearch in Eureka ↗ |
| Defendant counsel | Neil D Kelly | Attorney | Counsel for Ensign US Southern Drilling, LLCSearch in Eureka ↗ |
| Defendant law firm | Hunton Andrews Kurth LLP | Law Firm | Representing Ensign US Southern Drilling, LLCSearch in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | Texas Southern District CourtSearch in Eureka ↗ |
Official order — verbatim text
The court’s Order of Dismissal was entered on Judge Andrew S. Hanen’s signature granting docket entry 89 — the parties’ Joint Stipulated Motion to Dismiss With Prejudice. The with-prejudice designation is dispositive: it extinguishes C&M’s infringement claims against Ensign on the asserted patents as a matter of res judicata. Because the dismissal was jointly stipulated rather than unilaterally filed by the plaintiff, it is consistent with a negotiated resolution. No merits findings, claim constructions, or invalidity rulings are embedded in the order.
US10976016B2 & US10900626B2 — Oilfield Lighting Systems
US10976016B2 (application US17/016083) and US10900626B2 (application US16/571527) both relate to oilfield lighting systems — a product category that spans portable, rig-mounted, and zone-compliant illumination solutions used in oil and gas drilling and production environments. Both patents issued from applications filed in the 2019–2020 timeframe, placing them squarely in the modern LED and energy-efficient lighting transition for hazardous-area industrial use. The patents were asserted specifically against Ensign’s lighting system deployed in its US Southern drilling operations.
In the oilfield services market, lighting systems must meet stringent safety and hazardous-location ratings, and proprietary configurations can represent genuine competitive differentiation for equipment rental companies. C&M’s decision to assert two related patents simultaneously suggests these cover either complementary system configurations or method and apparatus claims designed to close design-around options. For competitors in the oilfield equipment rental and services sector, both patents remain active and judicially untested, representing a continuing enforcement risk for any company deploying similar lighting architectures.
Should you run an FTO against US10976016B2 and US10900626B2?
Any oilfield operator, drilling contractor, or equipment rental company currently deploying or procuring portable or rig-mounted lighting systems should treat these two patents as live enforcement risks. C&M Oilfield Rentals demonstrated willingness to litigate for over two years against a major international drilling contractor. No court has construed the claims or found either patent invalid — meaning their full scope as written remains enforceable against third parties in the sector.
PatSnap Eureka’s FTO Search Agent enables R&D and procurement teams to map the claim language of US10976016B2 and US10900626B2 against specific product configurations, identify design-around opportunities, and track the full patent families for continuation or divisional risk. Given the confidential settlement outcome here, understanding your own exposure before a demand letter arrives is materially more cost-effective than reactive litigation.
Run a freedom-to-operate analysis on US10976016B2 to assess your product’s exposure
Run FTO in Eureka →Similar oilfield equipment patent cases in Texas federal courts
Explore comparable patent infringement actions involving oilfield equipment and energy sector technology litigated in the Texas Southern and Western District Courts.
What this case signals for the oilfield lighting and equipment IP landscape
A two-patent infringement action resolved quietly in Texas raises important questions for operators and equipment renters across the oilfield sector.
With-prejudice dismissals after extended litigation typically signal a negotiated exit
When both parties jointly stipulate to a with-prejudice dismissal after more than two years of active litigation, market practice strongly suggests a financial or licensing resolution was reached. Competitors facing similar assertions from C&M should note that Ensign’s path — litigating through discovery before settling — appears to have resulted in a binding, permanent resolution rather than an open-ended licensing exposure.
US10976016B2 and US10900626B2 remain live enforcement assets against other parties
The dismissal creates no estoppel, no invalidity finding, and no claim construction precedent that other defendants could leverage. Any oilfield operator or service company deploying lighting systems with features that may overlap with these patent claims faces a clean enforcement risk from C&M. An FTO analysis against both patents is a prudent step before deploying or expanding such systems.
C&M v Ensign — key questions answered
C&M Oilfield Rentals filed a patent infringement action against Ensign US Southern Drilling and Ensign Energy Services in the Southern District of Texas on March 24, 2022, asserting US10976016B2 and US10900626B2 against Ensign’s oilfield lighting system. The case was dismissed with prejudice on May 3, 2024, pursuant to a joint stipulated motion signed by both parties, after 771 days of litigation.
The dismissal with prejudice bars C&M from re-asserting the same infringement claims against Ensign for the same accused conduct. However, both patents remain valid and enforceable against other parties. No court construed the claims or ruled on validity, so the patents’ full scope as issued is preserved for use in future enforcement actions against other defendants in the oilfield lighting sector.
The public record does not disclose settlement terms. However, a joint stipulated dismissal with prejudice after 771 days of active litigation is strongly consistent with a negotiated resolution — typically involving a financial payment, licensing grant, or operational undertaking by the defendant. Neither party has publicly confirmed any such arrangement.
C&M Oilfield Rentals was represented by Morgan, Lewis & Bockius, LLP, with attorneys including Elizabeth Mooar Chiaviello, Eugene S. Hwangbo, Jason C. White, Karon N. Fowler, and Susan Stradley. Ensign was represented by Hunton Andrews Kurth LLP, with attorneys Gregory Lawrence Porter and Neil D. Kelly.
Yes. The dismissal with prejudice only protects Ensign from re-litigation by C&M on these specific patents for the same accused conduct. Other oilfield operators, drilling contractors, and equipment suppliers deploying similar lighting systems remain fully exposed to enforcement by C&M. No invalidity finding, claim construction, or inter partes review outcome from this case limits C&M’s ability to assert these patents against third parties.
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