Experimental study on stress measurement for sound emission in carbonate formation

Based on the experimental study on the Kaiser effect for carbonate formation, the effect of different loading stresses and the time of core storage on Kaiser effect points for carbonate formation are analyzed. It is concluded that when the pre-loaded stress is 25% -70 % of the uniaxial strength and the time of core storage is 4 months, the Kaiser effect memory is the best. The distribution characteristics of the ratio of Felicity effect are discussed, the in-stress formula for carbonate formation which couples time and stress is obtained, and the method for stress determination in carbonate formation is generated. This method is applied to the stress measurement in an oil field in western China. The precision of the explained stress meets the requirements of engineering application. The problem of low precision of in-stress measurement for carbonate formation caused by time and stress sensitivity is solved. The proposed method improves stress measurement system and provides basic data for the efficient exploitation of carbonate formation.