摘要
克拉4井在膏盐岩井段钻遇了邻井未遇的超高压盐水层，压力系数达到2．47，先后采用了密度为2．50g／cm^3和2．82g／cm^3的压井液压井。该井在压井过程中，钻井液被高钙地层盐水严重污染，钻井液中Cl^-含量由144000mg／L升至182000mg／L，Ca^2＋由470mg／L升至6000mg／L，流动性变差，黏度和切力难以控制；同时使用了密度为2．4g／cm^3的储备钻井液，由于储备浆是回收的钻水泥塞、被溢流物污染的钻井液，钻井液成分复杂，改造难度加大。为了顺利钻穿此地层，采用了密度为2．53～2．56g／cm^3的钻井液。通过分析钻井液组成、影响因素及性能，优选出了加重材料，确定最优钻井液调整方案，及时清除了有害固相及离子，在较短时间内保证了钻井液具有良好的流变性能。现场应用表明，高密度钻井液性能稳定，抗污染能力强，顺利地钻穿了超高压盐水层。
An ultra high pressure saltwater zone, with a pressure coefficient of 2.47, was encountered in the gypsum/salt section of the well Kela 4, and the mud with densities of 2.50 g/cm3 and 2.82 g/cm3 failed to kill the well. The mud was contaminated severely by the saltwater during well killing, with a Cl- concentration increased from 144000 mg/L to 182000 mg/L, and calcium from 470 mg/L to 6000 mg/L. Mud became very viscous with poor fluidity. A recycled mud used for cementing drilling was also tried to kill the well, but failed. To drill this section, a mud with a mud density between 2.53~2.56 g/cm3 was used, and the weight material was optimized based on the filtrate analysis. Solids control equipment was used efficiently during drilling to promptly remove the drill cuttings, which was critical to the success of drilling.
出处
《钻井液与完井液》
CAS
北大核心
2007年第5期22-25,共4页
Drilling Fluid & Completion Fluid
关键词
高密度钻井液
老浆改造
井眼稳定
抗钙
抗盐
high density drilling fluids
old mud modification
wellbore stabilization, calcium tolerant
salt tolerant
