热释放解堵剂ThermAcid的室内研究

针对海上弱凝胶完修井液泥饼破除存在的作用深度有限、不能有效清除固相污染等问题，开发了ThermAcid热释放解堵剂。ThermAcid具有水溶性，且可缓慢水解释放出酸，因而能够有效地清除储层深部的污染物。水解动力学研究表明，ThermAcid的水解速度随pH值增大、温度升高而加快，碳酸钙溶蚀实验证实了上述规律。腐蚀速率实验表明：120℃下，ThermAcid对钢片的腐蚀速率为2.31 g/(m²·h)，低于5%盐酸对钢片的腐蚀速率(8.31 g/(m²·h))，有利于缓解井下钻具腐蚀。30 mD和400 mD砂盘破胶实验表明：与5%盐酸相比，ThermAcid破胶更均匀、更彻底，因而返排压力更低。

Laboratory Study on the Heat-Release Blockage Removing Agent ThermAcid

Weak gel fluid is used as completion and workover fluids in offshore oil and gas development. The mud cakes and the solids contamination resulted from the use of the weak gel fluids cannot be effectively removed. To deal with this problem, a heat-release blockage removing agent ThermAcid was developed. ThermAcid is water soluble, and can slowly release acid through hydrolysis reaction, thus can be used to effectively remove the contaminants left in the deep part of a reservoir. Hydrolysis kinetics study shows that the hydrolysis rate of ThermAcid increases with pH and temperature. Dissolution of calcium carbonate proves the above rules. Corrosion rate measurement shows that at 120 ℃, the corrosion rate of ThermAcid to steel plate is 2.31 g/(m2?h), less than the corrosion rate of 5% HCl, which is 8.31 g/(m2?h), and this is beneficial to the mitigation of corrosion to downhole drilling tools. Gel breaking experiments on 30 mD and 400 mD sand-beds show that compared with 5%HCl, ThermAcid breaks gel more uniformly and more thoroughly, and the flowback pressure is therefore lower.