低电阻率油层研究的3个尺度及其意义

在拉张的地质背景下，高束缚水成因的低电阻率油层形成于弱水动力变化带，水动力的强弱变化形成特殊的储集层岩性叠置结构(即不同的岩性按一定比例关系形成薄互层)，形成由微孔隙与大孔隙构成双组孔隙系统的油层微观组构，油层高含束缚水因而电阻率低，但其中较大孔隙储集可动油气，具备产能。以沉积相研究为指导，从沉积相、储集层岩性结构及储集层微观组构这3个尺度进行研究，有助于在弱水动力变化带寻找高束缚水成因的低电阻率油层。运用这一方法研究了大港油田港东开发区某断块，数口井见到增油效果。图2参16

Three standards for studying low-resistivity oil zones

Under an extensional geological condition, low resistivity oil zone caused by high irreducible water saturation is formed in weak and unstable water dynamic areas where the change of water dynamic results in special reservoir lithological structure. The micro-pores and macro-pores make up the dual-porosity pore system. The resisitivity is low because of the high irreducible water saturation, but the macro-pores accumulate mobile oil and gas. Based on the three standards as reservoir microscopic structure, reservoir lithological structure and sedimentary facies distribution, the distribution of low resistivity oil zone can be forecasted by the research on sedimentary facies. Improved yield has been achieved in several wells of Dagang Oilfield.