山东渤南油田古近系沙河街组沙二段及沙三段低渗透储层成岩储集相

渤南油田位于济阳坳陷的渤南洼陷内，是山东省胜利油田储量最大的亿吨级深层低渗透断块岩性油藏，主要含油层系为古近系沙河街组沙二段和沙三段，属中孔低渗透砂岩储层。低渗透砂岩储层的成因机理十分复杂，为了更精确地预测有效储层的分布及其内部储集性能的差异，应用成岩储集相的概念在渤南油田三区古近系沙河街组开展了低渗透储层质量评价的研究。该项研究是建立在储层沉积相、成岩作用研究的基础上，通过分析低渗透储层成岩作用对储集物性的影响及成岩作用阶段划分，认为造成本区储层砂岩渗透率较低的主要原因是成岩期各种自生矿物的充填和胶结作用。选用流动层带指标、孔隙度、渗透率、粒度中值、泥质含量、孔喉半径均值和变异系数等七项参数，采用聚类分析和判别分析方法，将渤南油田三区古近系沙河街组划分为四类成岩储集相，阐述了各类成岩储集相的特征，并结合沉积相，实现了成岩储集相的时空展布。研究成果将对低渗透砂岩储层的开发起到指导作用。

Diagenetic reservoir facies of low permeability reservoir of the Member 2 and Member 3 of Shahejie Formation of Paleogene in Bonan Oilfield, Shandong Province

The Bonan Oilfield is located in the Bonan Sag of Jiyang Depression, and is a deeply buried low permeability faulted lithologic reservoir with the largest oil reserves in Shengli Oilfield of Shandong Province. The main oil -bearing strata are in the Member 2 and Member 3 of Shahejie Formation of Paleogene with a low to middle porosity and a low permeability. The low permeability reservoir is characterized by its complex genetic mechanism. By employing the concept of diagenetic reservoir facies, the evaluation of reservoir quality in the third area of Bonan complex oilfield was made in order to predict the distribution of effective reservoir and its storage capacity more accurately. The research on sedimentary facies and diagenesis of the reservoir combined with analyses of diagenesis effect of low permeability reservoir on the reservoir property and with the division of diagenesis stages indicates that the genetic mechanism of the low permeability reservoir in this area is the filling and cementation of autogenetic mineral during diagenesis. Using seven chosen parameters including flow zone index, porosity, permeability, median grain size, mud content, median pore throat radius and variance coefficient, and applying cluster and discriminant methods, four kinds of diagenetic reservoir facies were classified. Combined with the analyses of their characteristics and sedimentary facies, the time-space distribution is also given.Our result provides a guide to the development of low permeability oilfield.