1. Exploration & Production Institute, Southwest Oil & Gas Branch Co., SINOPEC, Chengdu, Sichuan 610041, China;
2. Key Laboratory of Multi Components Seismic Technology, SINOPEC, Chengdu, Sichuan 610041, China;
3. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu, Sichuan 610059, China;
4. College of Geophysics, Chengdu University of Technology, Chengdu, Sichuan 610059, China;
5. College of Earth Science, Chengdu University of Technology, Chengdu, Sichuan 610059, China
Abstract：Jinma-Yazihe nappe tectonic belt in Longmen Mountain is characterized by complicated surface and subsurface,and it is very difficult to predict reservoirs and fractures in this belt. According to geological background and geophysical features in the area,and logging responses of dolomite,limestone,and gypsolith,we calculate rock brittleness and fracture parameters based on seismic data,and obtain the following observations:①The spatial distribution of high-quality brittle reservoirs and fracture development characteristics are predicted based on brittleness differences between dolomite and limestone reservoirs and overlying mudstones,and between dolomite and limestone reservoirs and underlying gypsum rocks calculated on logging and seismic data. ②In the upper sub-Member of Leikoupo Formation,there are structural and non-structural fractures; their distribution has a close relationship with tectonic,sedimentation,and other factors; and fractures developed differently in gas traps. ③High-quality reservoir characteristics can be clearly identified based on rock brittleness differences and relationships between the brittleness and fractures; however the fractures in brittle reservoirs cannot quantitatively be predicted due to brittleness coefficient accuracy and seismic data resolution. ④In the upper sub-member of Member 4,Leikoupo Formation,dolomite and limestone reservoirs have high porosity,strong brittleness,and developed fractures,they should be key targets for the gas development. The above observations have been approved by the drilling results of Well PZ1 and Well YaS1.
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