可循环微泡沫钻井液的防塌机理及应用研究

Anti-sloughing Mechanism Study and Application of Circulating Micro-foam Drilling Fluid

微泡沫钻井液是有效解决井漏的钻井液体系之一,但其稳定井壁的效果有待验证,并成为了是否选择微泡沫钻井液施工的关键因素之一。总结提出了微泡沫钻井液稳定井壁的7种作用机理,实验对比研究了常规水基钻井液与微泡沫钻井液的稳定井壁效果。结果表明,微泡沫钻井液的井壁稳定能力较常规水基钻井液更强,为现场施工选择微泡沫钻井液提供了理论基础和实验依据。成功的现场试验表明,微泡沫钻井液不仅可以有效防止井壁坍塌、井漏等复杂事故,还可提高钻井速度、保护油气层、节约钻井成本。

Micro-foam drilling fluid is one of the best muds to effectively resolve the lost circulation, but its effectiveness of well bore stability is unknown. It becomes one of the key elements to choose it or not. Seven mechanisms of micro-foam drilling fluid to stabilize wellbore were generalized and proposed. The wellbore stability effectiveness of commonly water-base drilling fluid and micro-foam drilling fluid was comparatively studied in lab. The results indicated that the micro-foam drilling fluid had a more powerful capability to stabilize the wellbore than water-base drilling fluid, which provides a theory foundation and experiment basis for choosing micro-foam drilling fluid or not. The successful field test indicated that micro-foam drilling fluid could not only effectively avoid sloughing and lost circulation, but also improve the ROP, protect reservoir and save the drilling cost.