井壁稳定性预测方法研究与应用

井壁失稳问题一直是钻井过程中经常遇到的难题。井壁失稳不仅会造成巨大的经济损失，而且决定着钻井工程的成败；因此，寻找一种钻前预测井壁稳定性的方法，以制定相应措施保证成功钻进，这也是亟待解决且对钻井工程有着重大意义的课题。影响井壁稳定的因素多而复杂，目前还没有能够普遍应用的井壁稳定性预测方法。为此，在研究传统井壁稳定性分析方法的基础上，提出了利用黏土矿物理化性能参数预测井壁稳定性规律的模糊综合评价法。在应用过程中对该方法进行了改进：引入层次分析法确定权重，减少了人为因素对模糊评价结果的影响；采用最大隶属度原则分析得出评价结果，增强了预测结果的准确度。在海拉尔地区的应用表明，该方法预测油气井井壁稳定性可信度高，实用性强。

As a difficult problem, wellbore instability problem has been besetting drilling workers all the time. Not only does it cause huge economic losses, but also it determines the success or failure of drilling engineering. Therefore, in order to formulate corresponding measures to ensure successful drilling, searching for a kind of method to predict wellbore stability before drilling becomes an imperative and significant topic for drilling engineering. Due to the complex relationship between various factors which influence wellbore stability, it hasn′t been found a widely applied method to predict wellbore stability so far. On the basis of studying traditional wellbore stability analysis method, the fuzzy comprehensive evaluation method is put forward to predict wellbore stability regulation using physico-chemical performance parameters of the mineral. This method has been improved by introducing the Analytic Hierarchy Process (AHP) and the Maximum Subjection Principle in the application process. After introducing Analytic Hierarchy Process to identify weight, and Maximum Subjection Principle to obtain evaluation results, it has reduced the influence of human factors and enhanced the accuracy of the fuzzy evaluation results. The application in Hailaer Area indicates that this method has high credibility and strong practicability to predict the wellbore stability of oil-gas well.

10.6056/dkyqt201501024