Experimental device for rock fracture under action of liquid nitrogen cold shock

Abstract

The invention discloses an experimental device for rock fracture under the action of liquid nitrogen cold shock, and belongs to the technical field of mechanical rock tests. The experimental device adopts the structure as follows: a liquid nitrogen cooling hole is formed in the central position of a rock sample; a plurality of temperature sensor holes are formed in the periphery of the liquid nitrogen cooling hole; rock sample temperature sensors are mounted inside the temperature sensor holes; a plurality of strain gauges and a plurality of sound transmitting and collecting units are arrangedon the surface of the rock sample; a Dewar flask is sequentially connected with hydraulic equipment, a first valve and the liquid nitrogen cooling hole in the rock sample through pipes; the liquid nitrogen cooling hole is sequentially connected with a first pressure reducer, a second valve, a second pressure reducer and a gas-liquid separator through pipes; a liquid-phase way of the gas-liquid separator is connected with the Dewar flask through a pipe, and a gas-phase way of the gas-liquid separator is connected with a gas collector with a sealing plug through a pipe. The experimental devicecan achieve a rock fracture process experiment under the action of low-temperature liquid cold shock, can measure the variation and the distribution of the temperature of the rock sample in a liquid nitrogen cooling environment, and can achieve real-time monitoring on rock destruction in a continuous low-temperature environment.

Description

technical field [0001] The invention relates to an experimental device for rock fracture under the cold impact of liquid nitrogen, belonging to the technical field of rock mechanics tests. technical background [0002] Existing oil stimulation measures (EOR) mainly include maintaining formation pressure (water injection, gas injection, etc.), changing pore fluid properties (polymer injection, steam injection, etc.) pressure, etc.) and other methods. Hydraulic fracturing technology is widely used, but its main purpose is to increase the length of cracks, but its effect on increasing crack density is limited. If the temperature of the rock is lowered, the tensile stress will be very obvious, which will more easily lead to the generation and expansion of new cracks in the rock. The tensile properties of the rock are low, and if the tensile stress generated during the cooling process is large enough, it is easy to cause the rock to break. [0003] This experimental device uti...

AI Technical Summary

Problems solved by technology

These experiments describe the change of rock properties after the rock specimen is destroyed, and lack the observation of rock crack propagation process under low temperature cold shock conditions, as well as the study of temperature distribution.

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