乌石凹陷低渗储层伤害机理研究与注入水源优选

针对乌石凹陷低渗强水敏储层水敏伤害机理认识不清制约注入水源选择的问题，通过铸体薄片、扫描电镜、图像分析、全岩分析等手段详细研究储层特征，由于储层中黏土矿物含量并不高，且膨胀性黏土矿物含量相对较少，因此，乌石凹陷低渗储层水敏伤害机理不同于常规储层水敏伤害机理。分析认为储层水敏伤害机理主要为在内表面水化过程基础上存在一定程度的渗透水化过程，即微观"速敏"现象。在此基础上进行储层配伍性实验和黏土膨胀抑制实验，评价注入水与地层水结垢和水驱油过程中黏土矿物膨胀、分散、运移对储层伤害的影响，指导油田注入水源优选，降低储层伤害风险。

Damage Mechanism Study and Injection Water Optimization of Low Permeability Reservoirs in Wushi Depression

In order to understand the water sensitive damage mechanism of low permeability water sensitive reservoirs in Wushi region and better choose the injection water source, reservoir characteristics were studied by means of casting thin sections, scanning electron microscopy, image analysis and whole rock analysis. Due to the low content of clay and expansive clay minerals in reservoir, the water sensitivity damage mechanism of reservoirs in Wushi region was different from the conventional ones. It was concluded that the damage mechanism of reservoir water sensitivity in Wushi region was mainly based on the internal surface hydration process, which has a certain degree of infiltration hydration process, namely the microscopic "velocity sensitivity" phenomenon. On the basis of mechanism analysis, the compatibility of water injection in low permeability reservoir was studied by using reservoir compatibility experiment and clay swelling suppression experiment. When considering the water flooding and the scaling between injection water and formation water, the influence of swelling and migration of clay minerals on permeability damage can be evaluated. Therefore, the optimization guidance of injection water source can be provided and the risk of reservoir damage is to be reduced.