硬石膏胶结的低渗透砂岩油藏水敏性伤害的微观机理

为准确认识江汉油田硬石膏胶结的低渗透砂岩油藏压裂过程中水敏性伤害的原因,结合储层地质资料,并通过原位扫描电镜、X射线衍射、薄片分析等方法对目标油藏进行储层伤害微观机理研究.结果表明:储层中作为胶结物的硬石膏导致的水化膨胀和溶解再沉淀,砂粒脱落是引起压裂过程中水敏伤害的主要原因.因此可以在压裂液中加入合适的阻垢剂,防治石膏引起的储层伤害问题.

Study on Microscopic Mechanism of Water-sensitive Damage of Low Permeability Sandstone Reservoir cemented by Anhydrite

In order to accurately understand the causes of water sensitivity damage during the fracturing process of an anhydrite cemented low-permeability sandstone reservoir in Jianghan Oilfield. this study used in-situ scanning electron microscopy, X-ray diffraction, thin section analysis and other methods, combined with reservoir geological data to analyze the microscopic mechanism of damage to the target reservoir. The results show that the hydration expansion, dissolution and re-precipitation of anhydrite as a cement in the reservoir and the shedding of sand particles caused by it are the main causes of water-sensitive damage during the fracturing process. It can be seen that adding a suitable scale inhibitor to the fracturing fluid can prevent and control reservoir damage caused by gypsum.