Experimental device and method for simulating shale gas-pressure pressing crack process

Abstract

The invention discloses an experimental device and method for simulating a shale gas-pressure pressing crack process, and belongs to the technical field of shale gas exploitation engineering. The experimental device is composed of a true triaxial loading unit and a gas-pressure pressing crack system unit. The true triaxial loading unit provides true triaxial stress loading, in the true triaxial stress state, the gas-pressure pressing crack system unit simulates the shale gas-pressure pressing crack process, gas-pressure pressing crack simulation indoor experimental requirements are met, gas pressurizing requirements are met, shale sample pressing cracks and crack growth are achieved, and waste gas recycling can be achieved; the stress-strain relationship of a shale sample can be measured before a gas-pressure pressing crack experiment, after the shale sample is pressed to be cracked through the gas pressure, changes of the permeability of the shale sample before and after pressing cracks can be further directly measured, and the pressing crack effect can be accurately evaluated; an experimenter can be assisted to find most proper pressing crack gas by changing pressing crack gas in a high-pressure gas bottle and can be assisted to research the shale crack fracturing mechanism, and a theory basis is provided for achieving pressing crack yield increasing.

Description

technical field [0001] The invention belongs to the technical field of shale gas exploitation engineering, and in particular relates to an experimental device and an experimental method for simulating a shale gas pressure fracturing process. Background technique [0002] As a kind of unconventional natural gas, shale gas’s exploitation technology is different from that of conventional natural gas, and mainly includes hydraulic fracturing technology and gas pressure fracturing technology, among which hydraulic fracturing technology is the most mature in the United States, but hydraulic fracturing technology The technology consumes a lot of water resources, and a large amount of chemical agents need to be added to the water, which leads to the pollution of groundwater. Therefore, from the perspective of environmental protection, hydraulic fracturing technology is not environmentally friendly. [0003] Gas fracturing technology, as the latest mining technology, has the advantag...

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Problems solved by technology

[0004] At present, in order to further study gas fracturing technology, it is essential to carry out fracturing simulation laboratory experiments, but the existing fracturing simulation laboratory experiments are all aimed at hydraulic fracturing technology, and are used for shale hydraulic fracturing. The experimental device cannot be simply transplanted or adjusted to a shale gas pressure fracturing experimental device, and some existing gas fracturing experimental devices can only meet the fracturing simulation indoor experiments under conventional triaxial conditions. At this stage, there is no shale gas pressure fracturing experiment device. The fracturing experimental device can meet the fracturing simulation indoor experiments under true triaxial conditions, but it cannot achieve the purpose of finding suitable fracturing gas, nor can it accurately evaluate the fracturing effect

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