渤海C油田明下段河坝砂体构型演化规律分析

Evolution of Channel-Bar Complex's Architecture Which Developed on Lower Minghuazhen Formation in Bohai C Oilfield

油田进入中高含水期后,剩余油分布研究是制定挖潜措施提高最终采收率的基础工作。基于高分辨率层序地层学理论和储层构型分析方法,综合应用岩心、测井及生产动态等资料,分析了研究区河坝砂体内部基准面旋回背景下的构型特征及演化规律,并建立了三种剩余油分布模式。研究表明,基准面升降控制沉积砂体的发育规模及空间叠置。在基准面上升早期及下降晚期,研究区储集砂体以河坝全叠置型为主,砂体规模较大,储层连通性及注水驱替效果较好,剩余油分布较少;随着基准面上升,储集砂体过渡为河道-河坝局部叠置型及河道型,砂体规模变小,储层连通性及注水驱替效果变差,剩余油分布较富集。该研究成果对同类型油田剩余油分布预测和油田注水方案编制均具有指导意义。

In the high water cut stage, research on residual oil distribution has been the fundamental task of making tapping measures and enhancing oil recovery. Based on cores, well loggings and production performance data et al, high-resolution sequence stratigraphic theories and architecture analysis method were synthetically applied to the study of channel bars architecture characteristics and evolution law, controlled by base-level cycles. Meanwhile,three different types of residual oil distribution patterns were built. The results showed that the developing scope and spatial overlaying styles of channel bars were controlled by base-cycles changes. During the period of late descending and early rising of base-level cycle, the reservoir was dominated by channel bar full overlaying sands, and the reservoir was more developed, its formation communication and injection-production performance were better, residual oil was relatively less;with the rising of base level, the reservoir was dominated by channel sands and channel-bar local overlaying sands, and the reservoir was relatively less developed, its formation communication and injection-production performance were worse, residual oil was relatively richer. The achievements and recognitions of this study had an effective guidance in water injection program establishment and residual oil distribution prediction.