双疏性表面处理预防致密储层水相圈闭损害实验研究

传统的屏蔽暂堵技术不能有效防止致密储层中工作液的侵入,而以往靠降低界面张力排驱液相的方法效果短暂。在工作液中加入氟表面活性剂,增大润湿接触角,是一种降低毛管力减弱毛管自吸的新方法。润湿实验筛选出能将致密砂岩由液润湿改变为气润湿的氟表面活性剂。100℃下将岩心片浸泡在含所选氟活性剂的滤液中处理40 min,岩心片与滤液和水的接触角分别为120°和110°。毛管自吸、岩心流动实验表明,处理后岩心总吸水量降低了60%,自吸速率较处理前降低了40%～50%,驱替速率约是处理前的2倍。表明,氟活性剂能够有效改变储层岩心的润湿性,具有预防水相圈闭损害的应用潜力。

Experimental Study on Amphiphobic Surface Treating to Prevent Reservoir from Aqueous Phase Trapping Damage

The traditional shielding temporary plugging technique can not effectively prevent the operating fluid from invading into tight reservoirs, while the effect of draining by decreasing the interface tension is always transient. Adding fluorochemical surfactant into operating fluid can increase the contact angle, which is a new way to reduce the capillary force and capillary imbibition. Wetting test was conducted to select the right fluorochemical surfactant which can change the reservoir wettability from liquid wetting to gas wetting. Slabbed core was soaked in the filtrate involving the selected surfactant at 100℃ for 40 minutes. The contact angle of filtrate and water on the treated slabbed core was 120° and 110°, respectively. Imbibition and core flow test showed that, compared with the untreated, water absorption decreased by 60%, imbibition rate decreased by 40%~50% and the displacement velocity increased by 2 factors. The results show that fluorochemical surfactant can alter the wettability of reservoir effectively, which has the potential for application in the prevention of water phase trapping.