Demystifying Tight–Gas Reservoirs Using Multi–Scale Seismic Data

摘要

Low permeability fluvial reservoirs in the US Rocky Mountain region are estimated to hold nearly 7000 tcf of gas reserves (DOE 2003). In a typical reservoir, several hundred feet of stacked sands are gas charged, with natural and induced fractures being essential for economic gas production. While “traditional” seismic data is useful for identifying major geologic interfaces and faults, the thin and complex nature of these channel sands are typically below seismic resolution confouding interpretation at the reservoir level. Extensive seismic experimentation has been performed over the Rulison “tight-gas” field in west-central Colorado, USA, as part of the multi-year Reservoir Characterization Project. The combined application of time lapse and multi-component seismic techniques provides unique insights into fault and fracture orientations and reservoir pressure changes resulting from gas production. An additional seismic technique, passive microseismic monitoring, is supplying an additional reservoir perspective, confirming hydraulic fracture orientation estimates and quantifying the effectiveness of well stimulation efforts. Integrated application of multi-scale seismic is demystifying tight-gas reservoirs.