The Seismic Prediction Of Reef And Reservoir Prediction In Sichuan Basin

With the rapid development of economy, the world's energy demand is more excuberant.oil resources as an important part of conventional energy sources has been coming more important. Now the key of oil exploration has shifted from structural reservoir to lithological reservoir. The reef reservoir, as the important type of lithologic reservoir, because of the excellent permeability and porosity, is a kind of excellent carbonate reservoir, and forms large reservoir. At the same time, because of high capacity and recovery ratio, the reef-type reservoir has attention of at home and abroad. However, because of the reef reservoir exploration starting later, in technology and theory needing development, the complex geological conditions of reef reservoir, and anisotropy, all those lead to seismic prediction difficulties to the reef reservoir.Sichuan Basin is a kind of typical carbonation basin. It with more layer system, large thickness, widely distribute has vast exploration prospects. Though oil exploration has a great success in Sichuan Basin and large reservoirs have been discovered. But the reef reservoir are deeply buried, dolomite reservoir and limestere rock speed and density difference is small, seismic reflection characteristics and reefs become poor, reservoir thickness thin, all those lead to increasing difficulty in oil seismic exploration.Based on the collected seismic data, log data, geological data, this text proceeds oil seismic exploration and get good results , achieve the expected purpose in L area .This text summarizes the reef characteristics on time section of ChangXing bed set in L area by seismic reflection analysis; divides reef reservoir's facies by waveform analysis technology, and obtains 4 seismic-deposition facies combining deposition characteristics in L area, of which the buildup and the foreslope facies are beneficial facies that establishes foundation for later reservoir prediction; describes the external form of reef effectively by paleogeomorphology restoration analysis; predicts growth facies of reef ChangXing bed set's reef reservoir by post-stack impedance inversion technology, and ChangXing bed set can be divided 3 parts and the upper part that distributes in the building and the foreslope facies is prospect reservoir; selects the sensibility attribution of L area—the RMS amplitude,the frequency attenuation,the main frequency,the first principal component etc. by post-stack seismic attribute which are identical with impedance attribute, and checks the prediction results successfully.In a word, these methods can forecast the favourable area of reef reservoir, which can provide reliable proofs for later well drilling deployment to reduce the risk of well drilling.