Research On Method Of Reservoir Prediction With Multi-component Seismic Data In Sulige Gas Field

The Sulige gas field in the Ordos Basin is the largest reservoir yet to be tapped in China.Its main pay zone is low porosity and low permeability with strong heterogeneity. Its sandbodies overlap one another and the effective reservoir is thin. A large overlap exists in theacoustic impedance of the gas-bearing sandstone and the surrounding rocks. In addition, thereis no unified interface between gas bearing layers and water bearing layers in Sulige,restricting the gas productivity construction. Therefore, it is a multi-solution problem tocharacterize the gas reservoir by the conventional P-wave seismic and it is difficult to identifyfluids.It is well known that P-wave data show the characteristics of a rock matrix and pore fluid,while S-waves only show the characteristics of rock matrices. At present, there are twomethods of obtaining S-wave data. One is by solving approximate equations by using thepre-stack inversion of P-wave data; although it is a lower cost method, it has lower precisionand poorer stability, and its results are ambiguous and hypothetical. Another method is byacquiring the S-wave or the P-SV wave through multi-component seismic exploration. TheS-wave or P-SV wave is acquired directly, not calculated, and has the advantages of betterstability and reliability. Thus the comprehensive application of multi-component seismic datahas more advantages than the P-wave seismic alone.This paper presents some key techniques for pre-stack reservoir characterization ofmulti-component seismic in our study, such as selecting the sensitive elastic parameters, themethod of matching of the PP and P-SV data, the pre-stack joint inversion of PP and P-SVdata, and the seismic elastic multi-parameter cross-plots technique. The technique forpre-stack reservoir characterization of multi-component seismic in Sulige gas field has beenproven to be effective and practical.