Energy Policy Act of 2005 (Ultra-deepwater and Unconventional Resources Program)
Reservoir Connectivity and Stimulated Gas Flow in Tight Sands
Colorado School of Mines (CSM), Golden, CO 80401
University of Colorado – Boulder, Boulder, CO 80309
Mesa State College, Grand Junction, CO 81501
iReservoir, Inc., Littleton, CO 80120
Production of natural gas from tight sandstone reservoirs is a complex interplay of flow from rock matrix to natural fractures, flow within complex networks of natural fractures, and flow within different complex networks of hydraulic fractures. In cases of such high complexity, no single technology or scientific discipline can alone tell the story. Instead, only an integrated workflow combining the clues from the various disciplines: seismic, rock mechanics, petrophysics, geology, and production, can stand a chance of realistically capturing the complexity of flow in fractured tight gas systems. For that reason, we have assembled a team covering all these disciplines and with experiences ranging from theory, through lab experiments to practical oil and gas field applications. Today’s common approach is to identify a gas-bearing zone and then – after the fact – find “sweet spots” where production wells hit the right combination of charge, permeability and accessible gas volume. Tomorrow’s “sweet spots” should be ‘engineered’, based on knowledge of what fracture patterns will result from a particular process, under conditions of known stress fields, in sand bodies with predictable connectivities, and with reservoir parameter distributions consistent with a well-documented rock body architecture.
The project will include the development of static reservoir models based on all available subsurface data at the Mamm Creek field, calibrated by LiDAR and other outcrop data from equivalent reservoir rocks on the adjacent outcrops at the Grand Hogback. These models will provide the ‘boundary conditions’ for geomechanical predictions of fracture propagation and the analysis of dynamic performance through multi-phase fluid-flow simulations. Rock mechanical modeling is included to try to predict fracture behavior in these specific rocks, and a complete suite of seismic data will also be used to document what the fractures actually do in nature. These include multi-component 3D, vertical seismic profiles, azimuthal AVO, and microseismic and electric (self potential) tools to monitor fracture propagation. Finally, in order to allow extrapolation of the findings at and around the Mamm Creek field to targets elsewhere in the Piceance basin, one project team will map the regional stratigraphic, structural and depositional systems trends to help identify conditions likely to be associated with “sweet spots”.
Principal Investigator: Dag Nummedal