坪北油田延长组沉积微相与油水生产规律研究

A Study of Yanchang Formation Sedimentary Microfacies and Its Oil-Water Production Rule in Pingbei Oilfield

坪北油田延长组湖盆东北部边缘河流入湖处,以三角洲相沉积为主,该三角洲前缘水下分流河道-河口坝微相过渡区域,储集砂体主要分布在水下分流河道上;长4＋52~长62小层储集砂体以水下分流河道微相砂体为主,占70%~75%,河口坝砂体占7%~10%,河道间湾砂体占10%~14%。通过对沉积微相及含油性变化的分析,认为该区沉积微相以水下分流河道为主,河道主体和河口坝微相为较好储层,但储层经过压裂改造后,在生产上并没有表现出更多的差异,油井产量分布主要受裂缝方向与井网、储层含油性及地层能量的影响。

River entrance into the lake at northeastern edge of Yanchang Formation lake basin in Pingbei Oilfield is characterized by delta facies sediment. Main reservoir sandbody takes up underwater by--channel. Underwater by-- channel rnicrofacies sandbody serves as the main body（taking up 70%--75%） in single layer of reservoir sand body from CA＋52 to C62, accompanying with mouth bar sandbody（7%-10%） and intercbannel bay sandbody（10%- 14%）. The analysis of sedimentary microfacies and oiliness change concludes that the sedimentary microfacies in Yanchang Formation is mainly distributed in underwater by--charmel and better reservoirs lie in major channel and mouth bar facies. However, they are not different in production after the reservoirs went through fracturing. Well yield depends on fracture direction, well pattern, oiliness and producing energy.