海上钻井多功能水基钻井液研究

Study on multifunctional water-based drilling fluids for offshore drilling

水基钻井液迄今仍然是海上钻井的首选钻井液。自20世纪90年代开始应用的正电聚醇钻井液和甲酸盐钻井液均具有良好的使用性能。为适应海上钻井需要而研制的新型正电聚醇-甲酸盐钻井液体系,兼具正电聚醇和甲酸盐钻井液的优点。在地层孔隙压力较低时,主要使用正电聚醇处理剂确保钻井液具有良好的性能;而在地层孔隙压力较高时,则配合使用甲酸盐进行加重,以维持一种性能优良的低固相钻井液体系。实验研究和现场应用表明,正电聚醇和甲酸盐的共同作用可使钻井液具有防塌、润滑、环保和储层保护等多种功能。

The usage of water-based drilling fluids is still the first choice for offshore well drilling. Since 1990s, both positive-charged polyglycol and formate muds have performed very well. To meet the requirements of offshore well drilling, this study developed a new type of positive-charged polyglycol/formate mud system by combining the advantages of the two additives. When the pore pressure is relatively low, the positive-charged polyglycol is mainly used to ensure the mud having good performance. When the pore pressure is relatively high, the formate is used as a weighting agent to maintain a low-solid mud system. The experimental study and field applications have indicated that the mud system has various functions such as anti-sloughing, lubrication, environment protection and formation damage control, etc., by virtue of the synergistic action of the positivecharged polyglycol and formate.