Geological Characters And Seismic Prediction Technique Of The Permian Reefs In East Sichuan

The reef oil/gas reservoir is a typical lithological oil/gas reservoir, as a result of the geological characteristic multiplicity and complexity, the exploration difficulty of reef reservoir is very big. In the full investigation, study and in the technical development foundation, in view of the reef reservoir's geological characteristics and the data base in Eastern Sichuan basin's Permian system, taking the reef reservoir as the object of study, analyzing the characteristics embarking from the known wells and seismic, through the seismic reflection structure analysis, the neural network waveform classification processing, the seismic attribute analysis, the three dimensional visualization interpretation, the multi-parameters seismic inversion and so on the many items of seismic special processing and interpretation methods, the paper has established reef and reef reservoir's distinction patterns, and formed the necessary seismic exploration technology. The paper's main research contents and the essential achievements are as follows:①Through the analysis of seismic reflection structure, distinguishes the distributed scope of a reef body effectively. The reef's contour is usually dome-shaped or lens shape bulge, the interior of a reef is usually multi-performance for off and on, disorderly or no reflection gap characteristics and so on. It can produce drape-like structure over top of a reef body, a reef flank deposit to the reef body boundary and so on.②Through analyzing of seismic waveform's overall characteristic changes, the special environment of deposition, the sedimentary face belt and the strata structure characteristics and some special recognition clues and signs of a reef on the seismic can be seen. The neural network technology, carries on the classification of seismic waveform, achieved the goal of predicting a reef's growth and distribution scope.③Carries on many kinds of seismic attributes analysis, causes the seismic signal difference in view of the reef, forecast reef's distributed scope, describes reef reservoir's anisotropic change. The seismic attributes analysis technology is effective in Huanglongchang field's 3-D seismic area reef forecast in the Eastern Sichuan. The reef's characteristic is obvious in the root-mean-square amplitude attribute.④In the Huanglongchang field's 3-D seismic dissection area of the Eastern Sichuan, the seismic amplitude, coherence and amplitude-frequency body were used as main attributes to process and explain reefs based on the three dimensional visualization technique, through many attributes and many kinds of visualization methods application, comprehensively forecasts the reef's distributed scope.⑤In the full analysis of reefs reservoir's lithological characters and electrical characters foundation, the gamma, compensation neutron and sonic velocity three electrical measurement curves which are quite sensitive to lithological discrimination were selected to establish the reef reservoir's geology model, and to establish the relation with the seismic information, carried on multi-parameters seismic inversion processing and interpreting, achieved the goal of lithology recognition and reservoir forecast. The gamma and compensation neutron inversion results were carried on the reef reservoir's recognition and forecast, and the sonic velocity inversion result was carried on study of a reef reservoir's porosity. The seismic reflection structure analysis, the neural network waveform classification processing, the seismic attributes interpreting and the three dimensional visualization explanation constituted the Permian reef's qualitative forecast and appraisal main technical series in the Eastern Sichuan. Take the gamma, compensation neutron, sonic velocity as the goal curves multi-parameters seismic inversion technology is the Permian reefs reservoir's quantitative forecast and l appraisal core technologies in the Eastern Sichuan.