鄂尔多斯气井钻井岩石力学特征描述难点及对策

鄂尔多斯探区的气井钻遇多套复杂地层,利用常规方法计算的地层坍塌压力、漏失压力、可钻性等钻井岩石力学特征参数误差较大,导致前期钻井施工中井壁垮塌与漏失严重、钻头选型效果不佳。针对鄂尔多斯气井钻井岩石力学特征描述的难点,根据工区实际情况完善了水敏性泥页岩地层坍塌压力计算方法、破碎性地层漏失压力求取方法、岩性多变地层可钻性分析方法,利用测井、钻井、地质、测试等资料描述了坍塌压力、漏失压力、可钻性的分布特征;并依据其提出了工程建议。在富县、定北工区的现场应用情况表明该方法具有较好的适用性,为优质快速钻井技术提供了准确全面的基础信息。

Difficulties of Drilling Rock Mechanics Characteristics Description and Its Countermeasures in Ordos Exploration Area

Gas wells in Ordos exploration area have complex drilling Geological condition, in which calculation of formation collapse pressure, leakage pressure and rock drillability using conventional method be in a larger error and leading to severe borehole collapse and leakage and poor effect of bit selection in early drilling. Aiming at the difficulties in drilling rock mechanics characteristics of gas wells in Ordos exploration area, collapse pressure calculation method of shale formation in water sensitivity, leakage pressure calculating method of fracture formation and rock drillability analysis method of complicated lithology formation are improved based on the actual situation of the area. According to the above methods, the characteristics of collapse pressure, leakage pressure and rock drillability was elaborated by using well logging, drilling, geology and test data, in which the engineering options was proposed. Applications in Fuxian and Dingbei area show that the proposed methods have better applicability and provide accurate and comprehensive basic information for high-quality and fast drilling technology.