The Study On Sequence Stratigraphy And Reservoir Prediction Of The Third Member Of Shahejie Formation Of The Palacogene In Qikou Depression

According to the theory of Sequence Sratigraphy, Sedimentology, Reservior Geology, Seismic Sedimentology and Hydrocarbon Accumulation Dynamic, on the basis of drilled cores, well logging and 3-D seismic data and multi-source flume experiment data, the study on ShaⅢ Member of Qishen Area in Eogene System are carried out and isochronous stratigraphic framework is set up. Combining the data of seismic data and well-logging data, reservoir prediction such as multivariate calibration, depositional body description, frequency division interpretation and constrained reversion are conducted. Emphasis is put on the fine study on depositional system, flume experiment, reservoir prediction, favorable reservoir and regular hydrocarbon accumulation.First of all, during sequence division, correlation and analysis, by Vail method, ShaⅢ Member is divided into 2 secondary and 3 the third class sequences. SQEs31 and SQEs32 are divided into 3 kinds of ST including LST, HST and TST. SQEs33 is divided into 1 HST and 1 TST. The comparable isochronous large section around Qishen Area is built and the hydrocarbon generating zone, reservoir, hydrocarbon migrating zone, trap, and cap of this area are studied, which guides the profitable area prediction.Secondly, depositional system study begins from provenance system analysis. By clustering method, and on the basis of seismic facies and attribute analysis, the major provenance system, LST range and depositional system distribution and evolution of various development stages of ShaⅢ Member are determined. The study result shows:Qishen Area is controlled by three provenance systems including Xiaozhan—Gegu provenance system in the north, Shen Qingzhung—Zeng Futai in the west and Zhou Qingzhuang in the south. Two provenance convergence centers consist of Banqiao Sag and Qibei Sag. Five depositional systems developed in ShaⅢ Member of Qishen Area are determined, which are fan delta system, braided delta system, near shore and offshore subqueous fan and lake system.The third, multi-source lab flume experiment is made for the first time which simulates the deposition of Kongdian braided delta of Sha Hejie Group in Qikou Sag and fan delta of Cangxian Uplift in the west. With the help of paleotopography, ancient landform and regional geology data of Eogene System in Qikou Sag, depositional patterns of various depositional systems are generalized, which indicates the direction for hydrocarbon exploration of Eogene System in Qikou Sag and further verifies the controlled factors that effect the wide range sandstone distribution in Qibei Slope are topographic slope, lake level, coming water feature, sand-mud ratio and source supply, among which sediment supply is the main factor determining sand-body deposition structure features.The forth, reservoir inversion and seismic attribute analysis are performed to make the fine inside structure characterization of ShaⅢ Member of Qikou Sag and Banqiao Sag. According to wave impedance change of gas-bearing interval and the clear lithologic downdip pinchout point, the gas-bearing interval location of Qishen 1 Area are interpreted and tracked.On the basis of above analysis, hydrocarbon accumulation zone in the deep layer of Qikou Sag is presented. According to the physical properties of reservoir and hydrocarbon control factors, favorable reservoirs are trapped and profitable exploration targets are proposed.