东濮凹陷北部沙三段页岩油成藏地质条件分析

Analysis of geologic conditions for Es_3 shale oil accumulation in the northern Dongpu sag

东濮凹陷北部沙三段泥页岩有机质丰度较高,热演化程度适中,含油泥页岩厚度较大,埋深条件较好。通过CT扫描、单偏光显微镜、扫描电镜、比表面分析及全岩分析,认为泥页岩储层孔隙总体以微裂缝为主,结构以中孔为主,脆性矿物含量较高,泥页岩含油率较高,同时盐岩广泛发育,为页岩油的保存提供了良好的条件。结合成藏地质条件、构造因素和常规油气富集条件,认为濮卫次洼、柳屯、胡庆地区为页岩油发育的最优有利区。

The Es3 mudstone /shale in the northern Dongpu sag has the features of high organic abundance,moderate thermal evolution,thick oil-bearing mudstone /shale and good burial condition. From CT scanning,single-polarizing microscope observation,SEM observation,specific surface area analysis and whole rock analysis,it is suggested that pores in the mudstone /shale reservoir is predominated generally by micro-fractures,the texture is dominated by medium pores,content of brittle mineral is high,oil-bearing capacity in mudstone /shale is high and salt rock was extensively developed,providing good condition for shale oil retaining.Taking into account of the geologic conditions for reservoir forming,structural factors and conventional oil and gas enriched areas,it is regarded that the Puwei sub-sag,Liutun and Huqing areas are the best favorable areas for shale oil developing.