甲酸盐钻井液技术在吐哈油田水平井的应用

吐哈油田目的层属低压、低渗储层,储层物性差,地层易破碎,粘土矿物含量高,页岩水敏性高,易发生漏失和坍塌。针对吐哈油田储层特点和水平井对钻井液的特殊要求,从改善润滑性、携岩能力、降滤失效果等方面对传统甲酸盐钻井液进行优化改造,形成满足吐哈油田水平井钻井需要的体系,并对体系性能进行评价,还制定出了合理的维护处理方案。现场应用表明,甲酸盐钻井液具有抑制性强、密度可调范围宽、流变性容易调控的特点,提高了井壁稳定性,解决了大井斜段水敏性地层的坍塌问题,而且对储层污染程度低,所形成滤饼容易被清除,保护油层效果好。

Application of Formate Mud in Horizontal Wells in Tuha Oilfield

The reservoirs in Tuha oilfield are low pressure, low permeability in nature. The petrophysical property of the reservoir is poor and the formations in reservoirs are easily broken up. The reservoirs also have high content of water sensitive clay. Mud losses and borehole instability are frequently encountered. Based on the feature of the reservoirs and the specific requirements on drilling fluids in this area, the formate drilling fluid was optimized in lubricity, cutting carrying capability and filtration, and a reasonable operation and maintenance scheme was designed to drill the wells in Tuha oilfield. Formate mud showed its advantages over traditional muds in shale inhibition, density control and rheology adjustment. Near gauge holes were drilled in deviated wells with high angles using formate drilling fluid. Contamination to the reservoirs from drilling fluids was minimized, and the filter cakes formed were quite easily removed, which gave birth to a satisfactory reservoir protection.