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川西坳陷须家河组是四川盆地天然气勘探开发的重点层位。该地层埋藏深、岩性致密、岩石硬度和抗压强度高,特别是须四底和须二段地层岩石可钻性级值高、研磨性强,导致机械钻速低、钻头使用寿命短,钻井成本高。针对须四底和须二段井下岩心,通过环境扫描电镜SEM和全岩分析测试XRD评价了岩石的微观结构特征及矿物组分识别,开展室内可钻特性试验测试获取了岩石硬度、研磨性和可钻性级值等可钻特性参数,并分析三者间的统计关系。分析结果认为,地层可钻性级值与岩石硬度和研磨性的相关性极小,传统微可钻级值不只是地层可钻特性的单一表现,应寻求一个新的可钻特性函数来描述地层可钻性与钻头破岩力学性态。该实验事实和分析结果为深刻分析岩石可钻特性和钻头选型提供实验支撑和技术参考。
Xujiahe Formation in West Sichuan Depression is the key layer of natural gas exploration and development in the Sichuan Basin. The stratum is deep buried with tight lithology and has high hardness and compressive strength of rock. In particular, the drillability of rocks in the strata to be eclipsed and to be strata should be high, which leads to low penetration rate, short service life of drill bits, Drilling costs are high. Aiming at the core of Xu 4 and Xu 2 sections, the microstructural characteristics and mineral component identification of rocks were evaluated by environmental scanning electron microscopy (SEM) and whole rock analysis (XRD). The indoor drilling characteristics tests were carried out to obtain the hardness, Drillability and other drilling parameters can be drilled, and analyze the statistical relationship between the three. The analysis concluded that the correlativity between drillability grade of formation and rock hardness and grindability is extremely small. The traditional micro-drillable grade is not only a single manifestation of formation drillability, but a new drillable characteristic function should be found to describe the formation Drillability and rock breaking mechanical properties. The experimental facts and analysis results provide experimental support and technical reference for the deep analysis of rock drillability and bit selection.