Research On Palaeogeomorphology And Sedimentary Of Lower Xingouzui Formation In Southeast Qianjiang Uplift, Jianghan Basin

The area Qiandongnan, in central Jianghan Basin and across over the two structural units Qianjiang Depresssion and Xingou Uplift, is the best area for the hydrocarbon generation in lower Xingouzui Formation in east Jianghan Basin.The theories and methods of many disciplines are applied in this thesis, including High Resolution Sequence Stratigraphy, Sedimentology, Petroleum Geology, Structural Geology, Seismic Stratigraphy and Palaeophysiography. With seismic data, log data, well data and core data available, and by tracing and correlating interfaces of the sequences, the lower Xingouzui Formation are classified into three III sequences, with the truncation or onlap unconformity and the correspondent conformity as the boundary.In the equitime sequence frame, the thesis researched on the distribution of microfacies and sandbodies by defining single well facies, drawing well tie section and analyzing seismic attributes, showing the historical and spacial evolution of the depositional system. The lower Xingouzui Formation evolved from expansion in SQXXIII to shrinkage in SQXXI. SQXXIII is dominated by underwater channel of fan delta front; SQXXII is dominated by distant bar and sand bar; SQXXI is dominated by mouth bar and underwater channel of fan delta front.According the theory of seismic sedimentology, and the heavy crop correlation and dispersed system analysis, it is pointed out in this thesis that besides Hanshui provenance and Hanchuan provenance, there is a newly found provenance from northwest, along the Houganglong Bay. The contemporaneous fault and palaeogemorphology is main the controlling factor to the deposit facies and distribution in the basin. Paleo-delves determine the development of underwater channels; paleo-bulge and paleo-wave base level control the development of sand bar; the structural slopes control the development of underwater channel.The lower Xingouzui Formation is a self-generated and self-reserved strata, with a layer of dense gyprock as the cap rock. The best reservoir is channel sandbody and sand bar in SQXXI, SQXXII and SQXXIII. According to the integrated assessment on the sandbody distribution, deposit facies, seismic attribute, palaeogemorphology and source rocks, it is concluded that the Zongkou Depression and Panchang Depression are the most favorable plays, including southeastern Jianxin Bulge, Zhilukou Structural Slope in Laoxin, Tuoshi Bulge and Northeastern Xingou.