Insights and Contributions from the Multiwell Experiment: A Field Laboratory in Tight Gas Sandstone Reservoirs

摘要

The U.S. Department of Energy's Multiwell Experiment (MWX) has led to insights and contributions into the technology for natural gas production from low permeability sandstones reservoirs in the western United States. Three wells, between 110 and 215 ft (34-66 m) apart at depth, have been drilled in the piceance Basin of Colorado, where the cretaceous-age Mesaverde, the formation of interest, lies at a depth of 4000 to 8250 ft (1220-2520 m). Tests have been conducted in the lowermost Corcoran-Cozzette marine sandstones and in the overlying paludal, coastal, and fluvial nonmarine intervals. Insights were gained in the areas of: (1) depositional environments, (2) natural fractures, (3) techniques for accurate reservoir assessment, (4) effectiveness of hydraulic fracturing, and (5) in situ stress behavior. Contributions to technology include: (1) improved core analysis capability, (2) demonstration of Stratapax/trademark/ core bits, (3) importance of depositional environments and natural fractures to tight Mesaverde production, (4) a computerized log analysis system and service, (5) new stress testing procedures, (6) detailed geologic and reservoir model for the Mesaverde, (7) factors affecting frac design, and (8) a comprehensive technical database for the Mesaverde. The paper draws upon several years of MWX results to illustrate these insights and contributions which have enhanced industry's ability to recover gas from this large resource. 99 refs., 2 tabs. (ERA citation 13:053088)