Method and device for ground stress testing reproducing wave velocity

Abstract

The invention discloses a method and a device for ground stress testing reproducing wave velocity. Three-dimensional rock wave velocity is tested and calculated under an in-situ stress state on a borehole wall, and then an oriented rock test piece is taken back from protolith, and a maximum acoustic wave direction is processed, that is, a rock test piece in a maximum stress direction, and a compression test and an acoustic wave test are performed under side pressure. The pressure under which wave velocity of the test piece is equal to the maximum wave velocity of a drill hole is selected as maximum stress of borehole protolith, and a maximum acoustic wave direction is the maximum stress direction of the protolith. The method and the device utilize positive correlation between rock wave velocity and ground stress, and wave velocity variation under the ground stress is generally in a favorable condition of 5% to 20%, so as to ensure test accuracy of the ground stress and fill defects ofa rock acoustic emission ground stress test method. The test principle of the method and the device is simple, the device is light, and test accuracy of the ground stress can be improved from e orderof magnitude.

Description

technical field [0001] The invention belongs to the technical field of geophysical exploration, and in particular relates to a ground stress testing method and device for reproducing wave velocity. Background technique [0002] The existing rock acoustic emission (kaiser effect) in-situ stress test is to retrieve the oriented rock specimens from the original rock, conduct acoustic emission tests on the rock specimens processed in different directions, and measure the kaiser point to find out The maximum pressure that each specimen has been subjected to before is taken as the current stress. However, the original rock has been squeezed many times in the multiple structural historical evolution of the formation, the maximum pressure obtained by the Kaiser effect is not necessarily the current pressure, and the direction of the maximum pressure in the past is not necessarily the current stress direction. The strain recovery method is also a test method of in-situ stress. Its p...

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Problems solved by technology

The strain recovery method may obtain the current stress of the original rock, but it is an indirect measurement method. The processing and calculation of the elastic recovery and the measurement and processing of the anelastic recovery are a very complicated process. In addition, the strain of anelastic recovery is generally 0.01% to 0.3%, which is difficult to measure, establish a constitutive model, and not easy to fit and calculate.

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