Sandstone gas reservoir simulation and analysis based on diffusive-viscous theory
Li Shikai1,2, Wen Xiaotao1, Ruan Yunqi1,3, Zhang Yijiang1, Liu Ting1, Cao Jun1
1. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu, Sichuan 610059, China;
2. Exploration Branch Co., SINOPEC, Chengdu, Sichuan 610041, China;
3. Southwest Petroleum Branch Co., SINOPEC, Chengdu, Sichuan 610041, China
Abstract：Seismic responses of gas and oil reservoirs can be contacted with frequency through the diffusive-viscous equation simulation theory,while white periodical layout sphere patchy saturated model is usually used to describe rock physics characteristics of classic gas bearing sandstone.According to the Johnson theory,the dispersion relation between seismic phase velocity and quality factor can be obtained by calculating the dynamic bulk modulus.Great seismic velocity difference can be observed when gas saturation in sandstones changes,the difference can be sometimes as high as hundreds of meters per second.When gas saturation is higher,seismic energy at high frequency attenuates more,but when gas saturation is higher,seismic energy at low frequency attenuates less.With the Carcione attenuation mechanism,the prestack diffusive-viscous wave equation,and the phase shift interpolation,we simulate seismic responses of three classic sandstone reservoirs.Some phenomena has been found:a.Gas saturation increase can lead to reflection remarkable "time delay" at reservoir low interface,and the dominant frequency declines in unconsolidated and medium consolidated sandstone reservoirs; b.Permeability increase can improve the fluid fluidity,but it has much less impact on seismic response of gas saturated reservoirs.
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