大港油田原始低电阻率油层地质成因分析

为寻找原始低电阻率油层 ,挖掘油田潜力 ,选取了大港油田原始低电阻率油层作为研究对象 ,进行地质成因分析。原始低电阻率油层是指油层电阻率原本就低而非受外在因素 (如泥浆侵入、层厚、上下围岩及测井系列等 )影响而形成的低电阻率油层。通过对原始低电阻率油层地质成因、机理的分析 ,发现形成原始低电阻率油层的主要地质成因是弱水动力沉积条件和成岩作用形成的次生孔隙。而这些成因则受沉积及成岩作用的控制和影响。因此 ,预测原始低阻油层的分布要从地质作用出发 ,结合对沉积条件、成岩演化、圈闭构造等的认识和成果来进行 ,最终确定形成低电阻率油层的有利地区。

The geologic genesis of original low resistivity oil reservoirs in Dagang oil field

The study on geologic genesis of original low resistivity oil reservoirs has been done in Dagang oil field for the sake of finding original low resistivity oil reservoirs and tapping the field potential. Original low resistivity oil reservoirs are those whose resistivities are low since they come into being. Their low values of resistivities are not due to exterior factors, such as invasion of mud, thickness of a layer, shoulder beds, or even different logging tools. The author finds that the low-energy hydrodynamic depositional conditions and secondary pores formed by diagenesis are the main geologic genesis of original low resistivity oil reservoirs. The geneses are controlled and influenced by sedimentation and diagenesis. Therefore, prediction for the distribution of original low resistivity oil reservoirs should be started with geologic process and incorporated with the sight and research results in depositional condition, diagenetic evolution, and trap structure.