【摘要】 目前,水基钻井液仍然是滩海钻井的首选钻井液。正电聚醇钻井液和甲酸盐钻井液自从20世纪90年代在现场应用以来,均表现出良好的性能。为运应滩海钻井的需要,充分发挥正电聚醇和甲酸盐的优势,研制出了一种新型的正电聚醇-甲酸盐钻井液体系。在地层孔隙压力较低或较高时,分别利用正电聚醇或甲酸盐作为主要处理剂以确保钻井液具有良好的性能并维持较低的固相含量。分析了正电聚醇、甲酸盐的作用机理及其协同增效作用。室内试验评价了该钻井液的抗温性、抑制性、保护油气层性能以及用甲酸盐加重对钻井液性能的影响。该钻井液在埕海4和庄海12井等进行了初步应用.在应用中钻井液粘度变化不大,埕海4井和庄海12井的平均井径扩大率分别为9.19%和6.91%,明显低于邻井;起下钻及下套管正常,无遇阻情况,电测顺利。室内试验和现场应用结果均表明,正电聚醇和甲酸盐的协同作用,可使钻井液具有防塌、润滑、环保和储层保护等多种功能。更多还原

【Abstract】 Currently, the water-based drilling fluid is the first choice for offshore oil well drilling. Since 1990s, both the polyglycol drilling fluids and formate drilling fluids have exhibited favorable properties. To meet the requirements of offshore well drilling, this study developed a new type of the positive-charged polyglycol/formate mud system by combining the advantage of the two additives. When the pore pressure is relatively low, the positive-charged polyglycol is mainly used to ensure the drilling fluids 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. Functional mechanism of positive-charged polyglycol and formate and their cooperation were discussed. At the same time, the fluid was evaluated on its thermal stability, inhibition and reservoir protection property. The effect of formate weighting on the fluid performance was also investigated. Pilot tests of this fluid were conducted in wells such as Chenghai4 and Zhanghail2. The fluid remained stable in these wells, the average well diameter enlargement ratio of Chenghai4 well and Zhang-hai12 well are 9. 19% and 6. 91% , which were obviously lower than that of the adjacent wells. No problems appeared in drilling, casing and logging. The experimental study and field applications indicate that the mud system has various functions such as anti-sloughing, lubrication, environmental friendly and formation damage control, etc. , by means of the coordinated action of the positive-charged polyglycol and formate.更多还原