Key technologies of tight gas reservoir prediction controlled by time-equivalent geological horizons
AbstractIt gets more and more attention for the low permeability tight gas reservoir exploration and development. As we know, resources of tight gas reservoirs in Sichuan basin are very rich, but there are many problems about seismic exploration to the tight sandstone gas reservoirs, especially application of effective reservoir prediction and fluid detection. Therefore, it is one of the points for tight sandstone gas exploration and development that how to find gas reservoirs with the value of industrial productions (sweet spot). Based on the geological features of tight gas reservoirs in Xujiahe of center Sichuan basin, analysis of rock physics and logging interpretations, this paper conducted AVO analysis and analyzed and selected lithology sensitive parameters, and then identified parameters of lithology and hydrocarbon. Moreover, we marked angle limited pre-stack seismic data with calibrated well loggings by seismic-well tie and studied the timeequivalent data. Controlled by time-equivalent geological horizons and rock physics characters, we established the key technologies of effective reservoir prediction and fluid detection in this areas, which are combination of pre-stack reservoir prediction techniques, such as pre-stack elastic parameters crossplot based on "S-wave virtual wells" and lithological facies fluid probability analysis, and fluid detection techniques, such as highlight volumes analysis and pre-stack attenuation in angle domain. The results of drilled wells show our good recommendation for well locations and prove that we accurately predicted the favourable gas reservoir distribution in Xujiahe formation of center Sichuan Basin.
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