Oil and gas litigation usually means document-intensive and expert-driven litigation, with a heavy involvement of mathematical models (for measurement, pricing, and damages). Holmes PLLC has experienced decades' worth of litigation, on both defense and plaintiff sides, in various upstream and midstream disputes.

James Holmes built his reputation in oil and gas litigation by working from 2000- 2010 to study Amoco’s and Shell’s legacy Permian Basin properties, acquired by Occidental Permian Ltd. (OPL) in 2001, and then challenging OPL’s gas-plant accounting practices in various courts of West Texas and East New Mexico. He challenged also the gas-plant accounting practices of Hess, ExxonMobil, Marathon, and their gas-plant co-owners. The litigation experience involved daily work in the American oil and gas industry’s most elevated and, in ways, most clandestine gas-processing arrangements; regulation of the interdependency of gas plants and mature oil reservoirs; cradle-to-grave marketing arrangements for gas-well gas; casinghead gas and crude oil; and enhanced oil recovery.

"Fighting OPL and its gas-plant partners for a decade left me with several gifts that I will use for the remainder of my career: (a) an intimate knowledge of upstream revenue and taxation accounting practices; (b) industry contacts, including many within the very companies I used to sue, for making markets for oil and gas; and (c) a motivation, whenever possible, to work profitably with large oil companies and pipeline companies rather than to carry on disputes with them in courthouses.”
– James Holmes, 2016