陕北斜坡东部低渗透储集层的有利沉积相带

Favorable Depositional Facies of Low Permeability Reservoir in Eastern Shaanbei Slope

根据岩心和250余口井测井资料分析,在对岩石类型及其组合、矿物组分、沉积结构、构造、测井相、生物化石、粒度特征分析的研究基础上,确认AS地区三角洲前缘长6水下分流河道微相、河口坝微相及其复合体是形成本区主要储集砂体的有利相带。由于受河流的控制和强烈影响,三角洲前缘相除发育水下分流河道外,各小层还发育河口坝被水下分流河道切割、叠置的复合型砂体。指出熏长611-2层水下分流河道、河口砂坝发育最好,水下分流河道汇合和超覆河口砂坝的作用更为强烈,更好地控制了该区主力油层的分布和连片范围。

Based on the core data and well logs from over 250 wells in studied area, the rock type and assemblage, mineral composition, depositional pattern, structure, log facies, biologic fossil and grain size feature are studied, by which it is confirmed that the underwater distributary channel microfacies, mouth bar microfacies and complex sandbodies which are cut and superimposed by the underwater distributary channels at mouth bar in Chang-6 formation of delta front in AS area could be as the favorable facies for forming the main reservoir body. The specific descriptions of the individual microfacies type, composition, characteristic, distribution and corresponding favorable areas were made, thus pointing out that the well developed underwater distributary channel and mouth bar in Chang-61-21 member allow their processes to better controls of continuous distribution and range of the major oil-bearing zone in this area.