盐岩地层地应力测试方法

A test method for the in-situ stress of salt rock

盐岩地层地应力是储气库形态设计、运行压力区间确定的重要影响因素,为了获得盐岩地层地应力参数,采用水压致裂法和多极子阵列声波测井计算盐岩地层地应力。针对盐岩的非渗透性特点,水压致裂法增加了回流工艺,在多个操作参数下进行多期裂缝重张测试,利用不同数据分析方法计算盐岩最小主应力得到了统一结果,误差低于5%。结合多极子阵列声波测井,分析了盐岩地层各向异性,依据密度测井资料和弹性波动理论,计算了地层水平主应力。阵列声波测井计算结果与水压致裂测试结果一致,测试盐岩地层中3个主应力值接近,为该地区盐穴储气库建设和优化设计提供了可靠的依据。

The in-situ stress of salt rock is an important influencing factor for the design of gas storage shape and the determination of operation pressure interval. To obtain the in-situ stress parameters of salt rock, the in-situ stress of salt rock was calculated by means of hydraulic fracturing method and multipole array acoustic logging. Considering the impermeability of salt rock, the hydraulic fracturing method was added with the reflow process. Multistage fracture reopening tests were carried out on various operation parameters, and the minimum principal stress of salt rock was calculated by using various data analysis methods. And thus, the results were consistent with the error lower than 5%. Then, the anisotropy of salt rock was analyzed based on multipole array acoustic logging, and horizontal principal stress of the formation was calculated on the basis of density logging data and elastic wave theory. It is shown that the in-situ stress calculated from the array acoustic logging data is consistent with the result of hydraulic fracturing test and the three principal stresses of the salt rock are close. The research results provide the reliable basis for the construction and optimal design of salt-cavern gas storage in this area. （2 Figures, 3 Tables, 23 References）