泥页岩中具有多种类型孔隙,为页岩油气富集提供了重要的储渗空间.恢复泥页岩孔隙演化史,是页岩油气资源评价与区带优选的关键,同时也是开展烃源岩排烃过程研究的重要基础.泥页岩中压实作用减孔、生烃作用增孔以及构造作用造缝是泥页岩孔隙形成的重要机制.基于这3种成孔机制,采用泥岩压实模型计算不同深度泥页岩孔隙度减少量,结合泥页岩的镜质体反射率、有机碳含量以及物性等实测数据,建立了地史演化过程中泥页岩有机质孔与有机碳变化量(ΔC)的数学模型;在拟合不同成因孔隙类型演化趋势模型的基础上,综合构造、岩相、成岩以及应力场特征,建立基于孔隙成因的多类型泥页岩孔隙恢复方法.应用该方法恢复了渤海湾盆地东营凹陷沙三下亚段3种成因类型孔隙的演化趋势,并预测了不同成因类型孔隙的空间展布,进而确定了其泥页岩总孔隙度的分布.预测结果与实钻资料较吻合,可靠性较好.%There are many types of pores in shale, which provide an important permeable-storage space for oil and gas enrichment. The restoration of shale pore evolution is the key to the evaluation of shale oil and gas resources and the optimization of zone, and it is also an important basis for the study of hydrocarbon expulsion process. The compac?tion of mud shale which reduces pore, hydrocarbon generation which forms pore, and tectonic effect which forms frac?ture are important mechanisms of shale pore generation. Based on these three kinds of pore forming mechanisms, a mudstone compaction model was used to calculate the porosity change of shale at different depths. The relationship between organic pore and organic carbon content during geologic evolution was modeled according to the measured data such as vitrinite reflectance, organic carbon content and physical properties of shale. After modeling the evolu?tionary trend of different pore types, a the multi?type shale pore recovery method based on pore formation was estab?lished based on comprehensive tectonics, facies, diagenesis and stress field characteristics. The evolution of three pore types in the lower part of the third member of Shahejie Formation in the Dongying Sag was restored by this method, and the spatial distribution of pores of different genetic types was predicted. The distribution of the total porosity of shale was determined. The forecast results are in good agreement with the real drilling data.
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