Texas courts have spent decades sorting out who owns what underground. The rule of capture lets a producer take oil and gas that flows naturally from a neighbor’s tract into its own wells, no compensation owed. Subsurface injection is different. When a midstream operator pumps foreign material into the ground and that material migrates into someone else’s mineral estate, the rule of capture doesn’t cover it. That’s trespass.
Todd Mensing, a partner at AZA Law, won a $41.8 million jury verdict in 2023 for SilverBow Resources in precisely this kind of case.
When Does the Clock Start?
One of the harder questions was timing. The Texas Supreme Court addressed the issue in a 2021 opinion, Regency Field Services, LLC v. Swift Energy Operating, LLC. The court held that for a mineral lessee, the cause of action accrues when contamination first interferes with the right to explore, produce, and possess minerals. That ruling defined which of SilverBow’s claims survived and which were time-barred.
Proving Trespass Below the Surface
The trial in McMullen County required the AZA Law team to prove that hydrogen sulfide and carbon dioxide from Energy Transfer’s disposal well had physically migrated, or posed the risk of migrating, into SilverBow’s leased acreage. That meant geological testimony establishing the projected path of injected gases through subsurface formations, petroleum engineering testimony on how the future migration disrupted operations, and economic testimony tying each dollar of damage to a specific cost.
Todd Mensing built the case around two core facts: the real risk of injected gases crossing lease boundaries, and the migration risk measurably impairing SilverBow’s ability to produce its own minerals. The jury found both to be true and awarded $24.5 million to SilverBow and $17.3 million to co-plaintiff El Dorado Gas and Oil.
“It is terrific to see the right thing happen,” Mensing said.
More Litigation From the Same Well
The same Tilden injection well has produced additional lawsuits. A separate case, Ageron Energy, LLC v. ETC Texas Pipeline, Ltd., reached the Texas Supreme Court after Ageron alleged that hydrogen sulfide destroyed its drill pipe when it attempted to bore through the contamination plume. That dispute raised related questions about standing and accrual in subsurface trespass cases.
AZA Law, formally Ahmad, Zavitsanos and Mensing, has earned recognition from Chambers USA in commercial litigation.
