抗高温高密度水基完井液沉降稳定性实验分析

Experimental Analysis on Settlement Stability of High Temperature Resistant High Density Water-based Completion Fluid

随着探井朝着深井、超深井的发展,高温、高压等复杂条件对完井液稳定性评价带来了难度,目前缺乏对高温高密度完井液沉降稳定性系统的评价标准。采用基于多重光反射原理的Turbiscan稳定性分析法对2.0 g·cm^(-3)高密度水基完井液在180℃沉降稳定性进行实验。结果表明:Turbiscan稳定性分析法利用动力学曲线图、稳定系数(TSI)可以有效地对高温高密度水基完井液沉降稳定性进行评价,该方法具有定量分析、操作简单、精度更高等优点。通过分别开展重晶石、膨润土、分散剂、抑制剂沉降稳定性实验分析,最终确定API重晶石与微粉重晶石复配比为7∶3、4%膨润土、3%分散剂TS、0.8%抑制剂DISP的高密度水基完井液具有抗高温效果,其在180℃高温下沉降稳定性最好。本研究对抗高温高压水基完井液沉降稳定性定量评价及配置具有指导意义。

With the development of exploration wells towards deep wells and ultra deep wells, it is difficult to evaluate the stability of completion fluid under high temperature, high pressure and other complex conditions. The stability of 2.0 g·cm^(-3) high-density water-based completion fluid at 180 ℃ was tested by the method of turboscan stability analysis based on the principle of multiple light reflection. The results showed that the method of turboscan stability analysis can effectively evaluate the settlement stability of high-temperature and high-density water-based completion fluid by using the kinetic curve and stability coefficient(TSI). The method has the advantages of quantitative analysis,simple operation and high reliability,high precision;Through the experimental analysis of barite, bentonite, dispersant and depressant settlement stability, it was finally determined that the water-based completion fluid with the ratio of API barite to micropowder barite composite 7∶3, 4% bentonite, 3% dispersant TS and 0.8% depressant DISP had high temperature resistance effect, and the best settlement stability at 180 ℃. This study has guiding significance for quantitative evaluation of settlement stability and configuration of HTHP water-based completion fluid.