In-situ stress determination at great depth by using acoustic emission technique

In this paper, the principle of in–situ stress determination at great depth by using acoustic emission (AE) technique is presented. A new method is proposed to accurately measure the three principal in–situ stresses by means of repeated loading on the core sample, based on the Kaiser effect and incomplete erasion phenomena of AE activity. The preparation of rock sample, experimental procedures and data processing method are also introduced. In addition, the effetcs of rock types, experimental parameters and the core preservation time on test results are also investigated. The results agree well with the in–situ stresses measured by hydrofracturing method at three oil fields in China, which proves the applicability of AE method for in–situ stress measurement.