Overlying formation pressure,fault dip angle and shale content are the significant parameters for fault sealing capacity evaluation,and the reliability of evaluation results depends on the accuracy quantification of these 3 parameters.In the research of fault sealing of the central-southern Liaoxi Uplift,it is found that the actual overburden density increases with the increase of compaction.Overburden density function was obtained by density logging and depth regression,and then it was integrated to calculate the overburden pressure.The fault dip angle changes with lithology and stress,and it was calculated by 3D seismic interpretation results and spatial stereo method.The overall trend of mud content was determined according to the seismic data,and then it was corrected by well logging gamma value to obtain the more accurate shale content in fault zone.The 3 parameters of No.1 Liaoxi Fault and its branched faults in the research area uplift were calculated accurately,and then their products were used as the fault sealing indexes.Combined with the analysis of differences in oil and gas distribution,it is found that the sealing capacity of the northern section of the study area is the best,followed by the southern section,and the central part is the worst.The lower limit values of fault sealing index are related to the physical properties of oil and gas,and the lower limit values of natural gas,normal oil and heavy oil are 9.34,8.31 and 6.12,respectively.%上覆岩层压力、断层倾角和断裂带泥质含量是断层封闭性计算的重要参数,对这3个参数的准确量化,决定计算结果的可靠性.在辽西凸起中南段断层封闭性研究中,发现上覆岩层密度随压实作用增加而增大,通过密度测井与深度回归获得上覆岩层密度变化函数,并对其积分,求取上覆岩层压力;断层倾角会随岩性、应力发生变化,利用精细三维地震解释成果,并运用空间立体几何计算断层倾角;根据地震资料判断泥质含量整体趋势,并结合自然伽马测井计算值进行井点校正,以获得更为精确的断裂带泥质含量;准确求取研究区辽西1号及其分支断裂的这3个参数,并以其乘积作为断层封闭指数.分析油气分布差异发现,研究区北段断层封闭性最好,南段次之,中段最差;断层封闭性下限与油气性质有关,天然气、正常油、稠油聚集的断层封闭指数下限分别为9.34,8.31和6.12.
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