Wide-azimuth Young's modulus inversion and fracture prediction: An example of H structure in Bozhong sag
WANG Jianhua1,2, ZHANG Jinmiao1,2, and WU Guochen3
1. CNOOC Research Institute Co., Ltd, Beijing 100028, China; 2. National Engineering Laboratory for Offshore Oil Exploration, Beijing 100028, China; 3. School of Geosciences, China University of Petroleum(East China), Qingdao, Shandong 266580, China
Abstract:Buried hill structures are widely distributed in the Bohai Sea and the South China Sea. Affected by both structural stress and weathering corrosion, fractures are relatively developed in buried hills. As an important space for oil and gas storage and migration, fracture zones are key targets of oil and gas exploration in buried hills. Traditional fracture prediction based on seismic attributes has low accuracy due to the difference in AVO attri-butes between top and bottom layers. In this study, first based on the first-order perturbation approximation equation of HTI media and the relationships among elastic parameters, an azimuthal elastic impedance equation was derived, which is characterized by Young's modulus, Poisson's ratio and anisotropic parameters. Then the azimuthal elastic impedance inversion method was constructed according to the Bayesian theory, which avoids the influence of different AVO attributes on top and bottom layers. The reliability of inversion can be improved, and fracture prediction can be rea-lized by combining anisotropic inversion with azimuthal Young's modulus fitting. Finally, the method was used to predict the fracture development intensity and direction in the buried hills in the H structure of Bozhong sag. The data used is the first wide-azimuth data acquired offshore in China. The result has proved that the fracture prediction method is accurate and rational.
王建花, 张金淼, 吴国忱. 宽方位杨氏模量反演和裂缝预测方法及应用——以渤中凹陷H构造潜山勘探为例[J]. 石油地球物理勘探, 2021, 56(3): 593-602.
WANG Jianhua, ZHANG Jinmiao, and WU Guochen. Wide-azimuth Young's modulus inversion and fracture prediction: An example of H structure in Bozhong sag. Oil Geophysical Prospecting, 2021, 56(3): 593-602.
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