用强抑制性钻井液体系钻巨厚泥岩地层

针对新疆准噶尔盆地莫北油田中生界白垩系吐谷鲁组（300-3850m)泥岩地层水化膨胀缩径严重，阻卡频繁，地层造浆性强，钻井液流变性控制困难。电测1次成功率低的问题，采用了甲酸盐钻井液和钾钙基钻井液体系，并配合相应的钻井工程技术措施。现场应用表明，这两种钻井液体系具有较强的抑制性，有效地减轻了泥岩地层的水化膨胀，明显减少了由膨胀缩径引起的井下复杂情况，井壁稳定。井径规则；控制了钻井液的流变性，减轻了泥岩地层的缩径阻卡，保证了裸眼完井作业的顺利实施，提高了电测1次成功率；通过强化钻井工程技术措施。缩短了钻井周期，提高了钻井时效，节约了钻井成本，实现了二开裸眼完井，提高了经济效益。

High inhibitive drilling fluid for drilling mudstone formation of intense thickness

Formate drilling fluid system and kalium/calcium base drilling fluid system with corresponding engineering technologies have been used in Mobei Oilfield in Junggar basin to solve the problems such as severe hydration in mudstone formation, frequent bit balling, severe mud making, difficult drilling fluid rheology controlling and low completion logging success ratio, etc.. The field applications have shown that hydration can be reduced availably and contraction can be decreased markably because of the strong inhibition of both drilling fluid systems. Also, drilling fluid rheology can be improved and bit balling can be prevented with the using of both systems. The completion logging success ratio and drilling efficency have been enhanced based on intensifying technical measures and drilling cycle and cost have been reduced. Meanwhile, the drilling fluid systems have been used in open hole completion, thus, economic benefit has been increased.