Abstract: The formation mineral composition, micro structure and physicalchemical properties of representative shale samples of deep complex shale formation in Yuguo area of Tuha oilfield were analyzed by Xray diffraction, Scanning Electron Microscope, swelling and dispersion tests, specific surface area capacity measurement, specific water capacity and other experimental methods the mechanisms of wellbore instability in deep complex formation were made clear. A three cooperation principle for stabilizing wellbore by improving the performance of drilling fluid was put forward. This method includes the technologies of sealing and consolidating side wellbore physicchemically, enhancing inhibition against hydration and providing the effective stress support of reasonable drilling fluid density. The responding antisloughing drilling fluid which is suitable to deep complex formation in Yuguo area was developed by selecting all kinds of additives and optimized formulation. The site trial indicates that this drilling fluid has great capacity to antisloughing and sealing layer. The drilling fluid is easy to manage and maintain. Using this drilling fluid can improve drilling velocity and save drilling cost.

Key words: Wellbore stability,    ,  Instability mechanism,     ,  Multicomponent combination,    , Antisloughing drilling fluid

摘要： 针对吐哈油田玉果区块深层复杂泥页岩地层,选取代表性泥页岩岩心,通过X射线衍射、扫描电镜、 水化膨胀/分散、比表面积、比亲水量等测定,对该油田岩样进行了地层组构和理化性能分析,分析了该区块深部复杂地层井壁失稳的机理,提出了“物化封堵灢抑制水化灢有效应力支撑暠的三元协同防塌钻井液技术对策。通过单剂优选和配方优化,研制出了适合玉果区块复杂地层的防塌钻井液体系。现场试验表明,该钻井液体系防塌、封堵能力强,钻井液维护处理简单,使用该钻井液可以显著提高机械钻速,节约成本。

关键词: 井壁稳定,   , 失稳机理,   , 多元协同,     , 防塌钻井液