在含粘土的砂岩中,可发生两种地层伤害,都是由于粘土的水敏性引起的。一是由某些粘土的膨胀特性引起的。例如,当水出现时,蒙脱石趋于膨胀。产生对地层堵塞; 二是一些低膨胀的粘土,如高岭土使地层的渗透率降低,被认为是粘土颗粒运移的结果。地层中粘土处于高盐环境,通常它以絮状物出现。在用水基体系洗井时(不论是钻井或还是生产工作),粘土周围的离子强度被减弱,而离子絮状物周围的微粒随即发生膨胀。这种结果使得粘土重新分散,并运移到较小的孔隙中,形成微滤饼,从而造成堵塞或地层伤害。这个问题,可用泵入地层的一种电解质或一种 In clay-bearing sandstones, two types of formation damage can occur, both due to the water-sensitivity of the clay. One is caused by the swelling properties of some clays. For example, montmorillonites tend to swell when water is present. Resulting in blockage of the formation. Second, some low-expansion clays, such as kaolin, reduce the permeability of the formation and are believed to be the result of clay particle migration. The clay in the formation is in a high salt environment, usually as a floc. When water-based systems are used for well washing (whether drilling or production), the ionic strength around the clay is weakened and the particles around the ionic flocs swell. This result allows the clay to redisperse and migrate into smaller pores, forming micro-filter cakes, causing clogging or formation damage. This problem can be pumped into the formation of an electrolyte or a