Permeability testing experimental method of reservoir core before and after hydraulic fracturing under triaxial stress condition

Abstract

The invention discloses a permeability testing experimental method of a reservoir core before and after hydraulic fracturing under the triaxial stress condition, successively comprising the following steps: (1) preparation of a test piece; (2) installation of the test piece; (3) installation; (4) temperature control and vacuum-pumping; (5) air inflation and adsorption equilibrium; (6) measurement of original permeability; (7) hydraulic fracturing of the test piece; (8) measurement of permeability after fracturing; and (9) adjustment of experimental conditions according to the formulated experimental scheme. The method provided by the invention can be adopted to carry out in situ accurate measurement of permeability of a reservoir permeable medium before and after hydraulic fracturing under the triaxial stress condition without pressure relief of the test piece. Thus, accuracy of the experiment is raised.

Description

technical field [0001] The invention relates to an experimental system, in particular to an experimental system for studying the combined action mechanism of unconventional gas fracturing and extraction. Background technique [0002] With the rapid development of the economy and the continuous progress of human society, the current large-scale production and large-scale utilization of conventional energy supply is increasingly unable to meet market demand. Under this severe energy situation, unconventional natural gas has shown huge resource potential, and my country's unconventional natural gas resources are very rich and have broad prospects for development. Unconventional natural gas will inevitably become an important source of future energy supply. Permeability of unconventional natural gas reservoirs is a physical parameter that reflects the difficulty of fluid seepage in the reservoir. Burial depth, permeable medium structure and geoelectric field are closely related,...

AI Technical Summary

Problems solved by technology

However, due to the lack of systematic scientific research, the lack of relevant hydraulic fracturing mechanisms, and the failure to quantify the relevant main parameters affecting the fracturing effect, the application and development of this technology in the field of unconventional natural gas reservoir permeability enhancement has been restricted. a certain degree of restriction

[0004] The existing experimental devices mainly have the following deficiencies: 1) The factors affecting the permeability considered are relatively single, and multi-physics field coupling experiments considering the stress field, seepage field, temperature field, etc. cannot be carried out; 2) If the permeability needs to be measured, The core needs to be taken out and carried out on another experimental equipment. At this time, the cracks in the core due to fracturing will be closed again, and the change of permeability before and after fracturing of the in-situ core cannot be measured quantitatively and accurately; 3) Most of the seepage experiments carried out It is a single water-phase or gas-phase seepage experiment, and the respective flow rates of water and gas cannot be accurately measured; 4) The vacuum degree inside the test piece cannot be measured, which is not accurate enough for experiments with gas adsorption; 5) The installation process is basically carried by hand , it is inconvenient and the process is not stable enough, which has a certain influence on the specimen

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