GRD聚合物环保钻井液在吐哈葡北油田的应用

Application of GRD polymer environment-friendly drilling fluid in Pubei area of Tuha oilfield

关键词:  葡北油田  复杂时效  膏质泥岩  聚合物环保钻井液  环境敏感性区块

Key words:  Pubei oilfield  complex prescription  salty paste mudstone  environment-friendly polymer drilling fluid  environment sensitive block

摘要:

针对吐哈葡北油田含盐膏质泥岩、大段煤层、硬脆性泥岩发育、地层孔隙非均值性大等难点,常规抗盐聚磺钻井液不能有效解决钻井过程中的塌、卡、划眼等复杂事故。在葡北3-25井试验应用GRD聚合物环保钻井液,钻井液流变性稳定,抗温达120 ℃,钻井液抗盐钙≥10 000 mg/L,钻井液HTHP失水量≤12 mL,泥饼黏滞系数为0.035～0.043；泥页岩滚动回收率达到90%以上。现场应用表明,GRD聚合物环保钻井液能够显著降低葡北油田钻井复杂时效,与抗盐聚磺钻井液相比,机械钻速提高19.37%,钻井周期缩短39.52%,完钻密度降低2.19%,井径扩大率缩小40.86%。试验井污水池呈土黄色,室内检测井浆EC₅₀>30 000,无毒,重金属含量达标,极易生物降解,能满足吐哈油田地层复杂、环境敏感性区块的钻井需要。 

Abstract:

Aiming at the difficulties of salt-containing paste mudstone, coal seam, hard brittle mudstone and strong formation pore non-uniformity, the normal salt-tolerant polysulfide drilling fluid applied in Pubei area of Tuha oilfield can’t solve the problems such as collapse, stuck and redressing in the drilling process. An environment friendly polymer drilling fluid formulated without sulfonated material was tested in Pubei area 3-25 well.The new drilling fluid has good rheological stability, the temperature resistance is up to 120 ℃, the anti-salt calciumis more than 10 000 mg/L, HTHP filtration loss is less than 12 mL, the mud cake viscosity coefficient is between 0.035 and 0.043, and the mud shale rolling recovery rate is over 90%. The field application shows that the GRD polymer environment-friendly drilling fluid can significantly reduce the drilling complex prescription of Pubei area. It is compared with salt-resistant polysulfide drilling fluid, the drilling rate increased by 19.37%, the drilling cycle was shortened by 39.52%, the drilling density decreased by 2.19%, and the diameter expansion rate decreased by 40.86%, no complexity. Cesspool color of the test well is yellowish. The indoor test shows that the slurry is non-toxic and has high biodegradability, slurry EC₅₀ is more than 30 000, and heavy metal content is up to standard, it, which can meet the drilling needs of complex and environment sensitive blocks in Tuha oilfield.