盐膏岩DRA-Kaiser地应力测试方法初探

RESEARCH ON GEOTRESS MEASUREMENT USING DRA-KAISER METHOD IN SALT-GYPSUM FORMATION

目前的地应力测量方法均不适合盐膏岩地应力测量,而现场需要盐膏层的地应力数据进行钻井设计,保证盐膏层钻井安全。为了解决该难题,首次采用DRA-Kaiser效应法测量盐膏岩地应力。结果表明,用DRA-Kaiser法相结合的方法,可以测量盐膏岩的地应力并提高试验结果的可靠性;当应力–应变差曲线上有拐点,且应力–声发射强度曲线上有明显增大的点,这时对应的轴压即为岩石所受的应力,避免了先前只用Kaiser效应法进行试验时出现多个Kaiser点的问题。

Currently,existing geostress measurement methods are not suitable for salt-gypsum formation,while it needs geostress data to do drilling design for ensuring drilling safety in salt-gypsum formation. To alleviate this problem,geostress of rock salt-gypsum for the first time by DRA-Kaiser method is measured. It indicates that combining DRA and Kaiser method could increase the credibility of test data. When the stress-strain difference curve displays inflection point,and stress-acoustic emission intensity curve has significantly increased point,the stress which corresponds to axial compression is the stress that rock suffered. It avoids displaying several Kaiser points in previous Kaiser effect experiments.