TX 75083-3836, U.S.A., fax 01-972-952-9435.
AbstractThe U.S. Department of Energy (DOE), National Energy Technology Laboratory has been conducting research on low permeability gas reservoirs for over 30 years. Major field experiments like the multiwell experiment and the multi-site experiment at Rifle, Colorado, have provided tremendous insight into the characterization of low permeability gas sands, the associated natural fracture network, and the implications of hydraulic fracturing. Since the early 1990's, the DOE has focused its research efforts on developing technologies and methodologies to detect and characterize natural fractures in the subsurface and on demonstrating methods for enhancing production.Several successful technology advances are expected to have significant impact on the recovery of natural gas from low permeability formations. A horizontal well recently completed at 15,000 feet in the Frontier Formation in Wyoming, in conjunction with Union Pacific Resources (UPR), initially flowed 14 MMcfd and in the first 9 months recovered 2.75 Bcf of gas. UPR has two more wells underway and plans to drill additional wells based on the success of this project. Natural fracture detection techniques have been successfully demonstrated in existing fields in the Piceance and Wind River basins. An integrated 3-D seismic and geomechanical modeling approach was demonstrated in the Piceance basin and more recently in conjunction with the horizontal well drilled by UPR/DOE. The use of 3-D seismic attributes was demonstrated in the Wind River Basin.DOE initiated several new projects to begin work in October 1999 that will (1) demonstrate the use of natural fracture detection technologies as an exploration tool and (2) advance the state-of-the-art in natural fracture detection by developing new techniques to quantify fracture properties that control the flow and transport of gas. This paper will provide a detailed discussion for the projects that have recently been completed and for the new projects along with their implications for enhancing gas production from low permeability gas reservoirs.