川中中台山地区侏罗系自流井组大安寨段致密油储层孔隙结构特征

Pore Structure Characteristics of Tight oil Reservoir in the Da'anzhai Member of the Jurassic Ziliujing Formation in Central Sichuan Basin

致密储层岩石孔隙结构对致密储层中油气的储集能力和渗流机理有着重要影响。为了更好的对研究工区内甜点进行有效的识别,进一步指导后续的致密油开采,笔者运用氩离子抛光扫描电镜技术、低温氮气吸附脱附法和高压压汞实验对川中中台山地区侏罗系大安寨段致密油储层的微观孔隙结构进行了详细的研究。研究结果表明:1川中地区侏罗系大安寨段致密储层孔径范围主要集中在微米-纳米级,孔隙类型可分为有机质孔、无机孔、裂缝,其中有机质孔对储层的贡献最大;2有机质孔内TOC的含量与有机质孔的数量,两者之间呈现较好的正相关;3致密储层微观孔隙结构类型复杂多样,孔径主要分布在3~30 nm,以中孔为主、大孔和微孔不发育;4黏土矿物含量、脆性矿物含量、有机碳含量、有机质热演化程度、成岩作用、保存条件共同影响着致密储层的孔隙结构。在上述研究的基础,分析了川中地区致密储层孔隙结果的影响因素,为后续的致密油甜点识别提供了地质依据。

The pore structure of tight reservoir is the main factor that influences the capacity of tight oil reservoir and the characteristics of seepage flow. In order to better the research area dessert for identification and further guide the subsequent tight oil extraction, the author uses the argon ion polishing scanning electron microscope tech-nology ,cryogenic nitrogen gas adsorption desorption adsorption method and mercury porosimetry experiments de-tailed research has been made on the micro pore structure of Sichuan in Taishan area of DAANZAI member in dense oil reservoir. The results of the study show that ： ① in Sichuan region of DAANZAI member in tight reservoir pore size of micron to nano scale, pore types can be divided into the hole of organic matter and inorganic pore, micro cracks, the organic pore the development; ② organic pore TOC content, between the two showed good positive cor-relation ;③ the tight reservoir, the types of microcosmic pore structure and complex, aperture main distribution in 3 -30 nm, dominated by holes, macropore and micropore agenesis; ④the content of clay minerals, brittle mineral content, organic carbon content, organic matter thermal evolution degree, diagenesis,preservation conditions of tight reservoir pore structure has an important influence. On the basis of the above research, the influencing factors of the pore result of tight reservoir in Central Sichuan are analyzed, which provides a geological basis for the subse-quent identification of dense oil.