强抑制性水基钻井液的室内实验研究

由于页岩地层水化作用较强,地层极易水化膨胀导致井壁不稳定,大量岩屑分散在钻井液中,引起钻井液流变性能的剧烈变化,井段容易发生井漏、垮塌、缩径等问题。针对这种情况,研发出一种抗高温抗污染的强抑制性水基钻井液体系。通过评价胺类页岩抑制剂UHIB-B和硅酸盐抑制剂Y1,两者的协同作用提高钻井液的抑制性能,并保持着较好的流变性能。该体系抗温达到了120℃,API滤失量小于3 mL,HTHP滤失量小于9 mL,测试其封堵性能时测得钻井液体系侵入沙床深度为1.8 cm,在膨润土以及无机盐的污染下,仍然保持着较好的流变性能,钻井液体系的岩屑回收率达98%,钻井液的防膨率达85%。试验表明,该套体系具有良好的流变性、抑制性及封堵性,抗温性能和抗侵能力优良,适宜在高水敏和易污染等复杂地层中使用。

Indoor Experimental Research on Strong Inhibitory Water-based Drilling Fluid

Due to the strong hydration of the shale formation, the formation is very easy to hydrate and expand to cause the wall instability. A large number of cuttings are scattered in the drilling fluid, causing drastic changes of the rheological properties of the drilling fluid, wells are prone to well leakage, collapse, shrinkage and other issues. In response to this situation, a high temperatureresistance, anti-pollution, strong inhibition water-based drilling fluid system was developed. By evaluating the synergistic effect of the amine shale inhibitor UHIB-B and the silicate inhibitor Y1, the synergistic effect of the drilling fluid was improved and the rheological properties were maintained. The system had a temperature resistance of 120℃, API filter vector was less than 3 mL, HTHP filter vector was less than 9 mL. When the sealing performance of the drilling fluid was measured, the invasion depth of the drilling fluid in the sand bed was 1.8 cm, and the rheological performance was still good under the pollution of bentonite and inorganic salt. The recoveries of the drilling fluid system were 98% and drilling fluid anti-expansion rate was 85%. Experiments show that the system has good rheological properties, inhibition and sealing, anti-temperature performance and anti-invasive properties. And it is suitable for high water sensitive and easy pollution and other complex formations.