黄河口凹陷古近系砂岩储层岩石学及成岩作用特征研究

Research on Petrology and Diagenesis Characteristics of Sandstone Reservoir in Palaeogene of Huanghekou Depression

黄河口凹陷古近系储集砂体类型和成岩过程复杂，为储层优选提供依据，需要全面总结黄河口凹陷古近系砂岩储层的岩石学特征和成岩作用特征。通过大量的基础分析测试工作以及钻井薄片观察，将杂砂岩和净砂岩的特征进行区分，明确了净砂岩是古近系的主要储层，并将其划分至3类8种成分-成因储层类型。黄河口凹陷古近系砂岩储层以长石砂岩类为主，地层单元由下至上石英砂岩类比例呈增加趋势，岩屑砂岩类呈减少趋势。砂岩成岩过程中经历了压实压溶、胶结、交代、蚀变、溶解、黏土矿物转化等6种成岩作用，储层岩石学特征的差异影响了不同层位储层的成岩作用及其储层物性。

Because the sand body type and diagenetic process were complex in the Palaeogene reservoir of Huanghegou Depression, for the purpose of providing the basis for the reservoir optimization, it was necessary to sum up the Palaeogene petrologic and diagenetic characteristics in the depression. Through plenty of basic analyses and drilling slice observation, the characteristics of greywacke and pure sandstone were distinguished and it was defined that the pure sandstone was the major reservoir in Palaeogene. And the pure sand reservoirs were divided into three types and eight kinds. In the Palaeogene of Huanghegou Depression, arkose was dominant. Meanwhile, from the bottom up, the proportion of quartz sandstone type showed increasing trend and lithic sandstone type was in decreasing trend. During the diagenetlc process, sand reservoir has experienced compaction pressolution, cementation, metasomatism, alteration, dissolution and clay mineral transformation. The whole diagenesis process and reservoir physical property in different zones are influenced by the differences of petrologic characteristics.