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

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.