胜坨油田沙河街组二段三角洲相储层特征及影响因素

胜坨油田沙河街组二段是主力产油层系,随着开发的深入,出砂、水窜等情况日益严重.因而,对其储层特征进行研究有助于进一步开发.通过对取芯井段的岩石薄片、岩心铸体薄片观察,结合沉积微相及储层物性资料的对比分析,对沙河街组二段下部三角洲相储层砂岩的岩石学特征、物性特征、成岩作用等作了较为详细的研究.研究表明胜坨油田沙二段三角洲相储层总体上为一套砂(砾)岩体,岩性以粉细砂岩为主,成分成熟度及结构成熟度均较低,但储层孔渗性较好,属于高孔高渗性储层.影响沙二段储层物性的影响因素很多,其中沉积相带对储层物性起控制作用;岩性特征对储层物性影响也较大;成岩作用对储层物性也有一定的影响,压实作用是导致原生孔隙度减小的主要原因,颗粒及胶结物的溶蚀是产生次生孔隙的主要因素.

Reservoir feature of the delta facies in the second member of Shahejie formation, Shengtuo Oilfield and its influencing factors

The second member of Shahejie formation is the main oil-production formation in Shengtuo Oilfield, and its reservoir characteristics must further be studied due to the serious sand flow and water-breakthrough caused by development. The lithologic characteristics, physical properties and diagenesis are studies in detail based on the observation of rock thin-section and core casting thin-section, and the analysis of sedimentary microfacies and reservoir properties. The study shows that, the reservoir is a set of sandstone body, its lithology is mainly siltstone, its compositional maturity and structural maturity are all lower, and it is high-porosity and high-permeability reservoir. There are many factors of influencing the physical property of the reservoir, among them, sedimentary facies belt has controlling effect; the lithologic characteristic has also greater effect; diageneses have a little effect, compaction is the major factor causing the decreasing of primary porosity, and the corrosion of particle and cenmenting matter is the main factor generating secondary pore.