Government and Regulatory Agencies: 3M CBM Model
San Juan Basin, USA
Norwest prepared a basin-wide coalbed methane reservoir model of the Colorado portion of the San Juan Basin for the Southern Ute Indian Tribe, the Colorado Oil and Gas Conservation Commission, and the Bureau of Land Management. The model, referred to as the 3M CBM MODEL, simulates the effects of production from all existing and proposed Fruitland coal wells in Colorado. The effects of dewatering, gas adsorption and desorption, and historical production are included in the model. The model also provides a technology to evaluate coalbed methane infill drilling and gas seepage at the outcrop.
Industrial and Manufacturing: LNAPL Remediation
An old chemical plant had accumulated at least 3 feet of thick benzene and styrene floating on groundwater in thick gravels, which periodically produced slicks on the Ohio River. Norwest performed site assessment, risk assessment. and pilot testing.
Initial mass reduction was accomplished by vapor extraction with a thermal oxidizer until vapor yield declined. Norwest then engineered a sparge fence along the riverbank and created sparging clusters in hot spots. Periodic air injection via a large underwater mobile compressor broke up floating hydrocarbon that essentially lifted vapors into the vadose zone and promoted aerobic biodegradation above and below the water table. This “biosparging” mode required no recovered vapor or water treatment, and no fugitive vapors were detected. Monitored oxygen and carbon dioxide in the vadose zone correlated with hydrocarbon destruction. The floating product was completely removed after one year of operation and groundwater quality was improved to the point of meeting risk assessment criteria.
Norwest remediated a site that had been a candidate for NPL listing in one year’s active operation, with no groundwater treatment and vapor treatment limited to an initial vapor extraction phase.
Mining: Regulatory Approval for Mine Lease Boundary Solution
Two adjacent oil sand mining operations were required to develop a mine plan for the common lease boundary area that would minimize resource loss while maintaining the integrity of the separate fluid tailings storage for each operator on their respective side of the boundary.
Norwest integrated the geological models, mine plans, and mining schedules for the two operations and developed a number of boundary solutions, ranging from a full in-place dyke of undisturbed material to a fully constructed dyke comprised of geotechnically competent waste material from the two operations. In all cases, the dykes were designed to meet the appropriate dam safety requirements for fluid storage.
The contending options were narrowed down to a small number of possible alternatives via a process of macro-level costing. Comprehensive mining schedules, boundary plans, operating and capital cost estimates, and resource loss estimates were developed for the final set of alternatives and reviewed with the two clients as well as representatives of the regulatory authority, the Alberta Energy and Utility Board.
The Board and both clients accepted the recommended alternative for implementation as part of the long-term mine and tailings plan for each of the operations.
Power Generation: CO2 Sequestration
Norwest is currently consulting for a confidential power generation company on plans to build a coal-fired IGCC power plant.
Project objectives are to identify the best CO2 sequestration options for the plant as well as conduct a comprehensive evaluation of oil reservoir candidates considered suitable for Enhanced Oil Recovery (EOR) or pure sequestration.
Phase 1 of the project included a comprehensive evaluation of possible sinks in a regional basis resulting in the selection and ranking of candidates in terms of available storage capacity and the possibility of combining storage and CO2-EOR. Future phases will include specific geological and engineering assessments of pre-selected potential sinks as well as support for regulatory filings.