用Amott/USBM法评价完井液及其组分对砂岩的润湿作用

AN APPRAISAL OF THE EFFECT OF COMPLETION FLUIDS AND THEIR COMPONENTS ON THE WETTABILITY OF SANDSTONE BY MEANS OF AMOTT/USBM METHOD

为尽量避免因完井液等外来流体引起的油藏岩石润湿性反转对储层的损害,用Amott/USBM法评价了国内部分常用的水基和油基完井液体系及组分,对天然砂岩油藏岩样润湿性的影响。评价结果表明,水基完井液及其处理剂对水湿砂岩的润湿性影响较小,但能较明显地降低油湿砂岩的亲油性。油基完井液及其多数处理剂对水湿砂岩的润湿性有很大影响,使其转变为油湿或中性润湿,并且使油湿砂岩的亲油性进一步增强。由于水基完井液有其它损害机理存在,因此它对砂岩油相有效渗透率的损害程度明显高于油基完井液。

To avoid the formation damage due to the wettability reversal of the reservoir rocks induced by external fluids, such as completion fluids, the effect of a few commonly used waterbased and oil-based completion fluids and the additives of these fluids on the wettability of core. samples of natural sandstone was evaluated. The results indicate that the water-based completion fluids and their additives have little effect on the wettability of water-wet core samples, but can make the oil-wet core samples less strongly oil-wet. The results also show that the oil-based completion fluids and a majority of their additives have significant effect on the wettability of water-wet core samples, resulting in a oil-wet or intermediate wet state. Furthermore,they can make the oil-wet core samples more oil wet. Since other damage mechanisms exist in water-based completion fluids,the extent of damage of oil-phase effective permeability to sandstone cores induced by water-based completion fluids is much higher than that induced by oil-based completion fluids.