| Fractures of tight sandstone reservoirs in the Upper Triassic Xujiahe Formation in the Xinchang area of the Sichuan Basin are generally developed,which affects the enrichment,productivity and development effect of natural gas.It is of great significance to study the development rules of reservoir fractures to increase natural gas production.In this paper,through the core,logging,3D seismic data and the finite element numerical simulation of reservoir geomechanics,the fracture development characteristics,control factors and distribution rules of tight sandstone reservoirs in the2 th and 4th layers of the Xuchang area are investigated.Comprehensive research and analysis of the impact of reservoir fractures on natural gas production.Research on core and imaging data shows: the tight sandstone reservoirs of the Xujiahe Formation in the Xinchang area mainly develop structural fractures,diagenetic fractures and abnormal high-pressure related fractures,among them mainly developed structural fractures,and the fracture directions are mainly near E-W,S-N,NE-SW and NW-SE direction.The development degree of reservoir fractures is affected by factors such as rock mechanics layer thickness,lithology,structural parts,abnormal high pressure,among them the structural factor have the most significant control effect on the distribution of reservoir fractures.The results of conventional logging fracture interpretation show: the cracks in the 2,4,5,and 7 layers of Xu 2 and the 3,7,8,and 9 layers of the Xu 4 are highly developed,which is a favorable development layer.On the plane,reservoir fractures are obviously controlled by faults and structure part.The results of post-stack seismic and finite element numerical simulation show: the closer to the fault,the higher the degree of fracture development.The fracture development area in the high structural part is the main favorable gas production area,while the lower part of the structure is dominated by water production. |
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