Supercritical carbon dioxide coal rock fracturing CT imaging and evaluation device under simulated in situ condition and use method thereof

Abstract

The invention discloses a supercritical carbon dioxide coal rock fracturing CT imaging and evaluation device under a simulated in situ condition and a use method thereof, belonging to the field of intensified mining of coalbed methane. The device provides a supercritical carbon dioxide fracturing device under a geological environment condition in which the size of a test piece is Phi 50*100 mm, anaxial pressure and a peripheral pressure of the test piece reach 50 MPa separately, environment temperature of the test piece reaches 100 DEG C, burial depth of a simulated coal bed reaches 2000 m. The device consists of an in situ environment simulation device, a CT scanning device, a supercritical carbon dioxide fracturing device, a penetration rate measurement device and a data collection device. By adopting the device provided by the invention, the defect that in existing laboratory study, crack patterns after supercritical carbon dioxide fracturing cannot be observed intuitively under the simulated in situ condition is overcome, the crack patterns in the coal after supercritical carbon dioxide fracturing can be observed in real time, and supercritical carbon dioxide fracturing effectcan be evaluated comprehensively by combining coal penetration changes before and after supercritical carbon dioxide fracturing.

Description

technical field [0001] The invention relates to a supercritical carbon dioxide coal rock fracturing CT imaging and evaluation device under simulated in-situ conditions and an application method thereof, belonging to the field of enhanced exploitation of coal bed methane. Background technique [0002] my country's coal seams contain abundant coalbed methane resources, however, the permeability of coal seams in my country is generally low, between 0.002×10 -15 ~16.17×10 -15 m 2 , where the permeability is less than 1×10 -15 m 2 The coal seams account for 72% of the total proven coal resources, and the low coal seam permeability seriously restricts the development of my country's coalbed methane industry. As a means to improve reservoir permeability, hydraulic fracturing has been widely used in coalbed methane exploitation in recent years. However, in the traditional hydraulic fracturing process, there will be water sensitivity phenomenon, which will affect the permeabilit...

AI Technical Summary

Problems solved by technology

At present, there are still deficiencies in the crack propagation mechanism in the process of supercritical carbon dioxide fracturing under in-situ conditions. In the laboratory research process, there are still monitoring methods used that cannot directly observe the crack shape, and it is still necessary to remove the test piece for observation, and It is impossible to evaluate the fracturing effect under in-situ conditions immediately after fracturing. Therefore, it is necessary to establish a supercritical carbon dioxide coal-rock fracturing imaging device and evaluation method under simulated in-situ conditions.

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