Hydraulic fracturing and microwave fracturing combined anti-reflection shale experimental device and method

Abstract

The invention discloses a hydraulic fracturing and microwave fracturing combined anti-reflection shale experimental device and method. The device comprises a triaxial pressure chamber unit, a confining pressure and axial pressure control unit, a hydraulic fracturing control unit, a microwave fracturing control unit and a permeation control unit. The method comprises the following steps: replacing a shale sample with a standard steel sample for volume calibration, and completing measurement of an upper permeation reference volume and a lower permeation reference volume through cooperation of the triaxial pressure chamber unit, the confining pressure and axial pressure control unit and the permeation control unit; dismantling the standard steel sample, installing the shale sample into a triaxial pressure chamber unit, and completing device connection; completing simulation of ground stress and formation temperature environment through the confining pressure and axial pressure control unit and a heater in the triaxial pressure chamber unit; completing hydraulic fracturing of the shale sample through the hydraulic fracturing control unit; completing microwave fracturing of the shale sample through the microwave fracturing control unit; completing permeation of the shale sample through the permeation control unit, and finally obtaining the permeability of the shale sample through calculation.

Description

technical field [0001] The invention belongs to the technical field of shale oil and gas exploitation, and in particular relates to an experimental device and method for combining hydraulic fracturing and microwave fracturing to increase permeability of shale. Background technique [0002] With the increasing depletion of energy resources, the exploration and exploitation of unconventional oil and gas resources have become particularly important. Shale oil and shale gas are typical extraordinary oil and gas reservoirs. my country's shale oil reserves are equivalent to conventional oil reserves, and shale gas reserves rank first in the world. Although my country's shale oil and gas resources are abundant, shale oil and gas reservoirs are tight and low-permeable, and their internal pores are not developed, making it difficult for oil and gas to flow inside shale. In addition, shale oil reservoirs are mostly organic-rich rocks of medium and low maturity. Crude oil in medium-ma...

AI Technical Summary

Problems solved by technology

Due to the limitations of test equipment and methods, most of the current research on microwave fracturing takes the sample out of the formation and directly places it in a microwave oven for microwave treatment. After the treatment, stress and fluid pressure are applied to the sample for mechanical or seepage test research. The problem with this kind of test method is that the ground stress on the sample before microwave is relieved, and the temperature is also reduced to a normal temperature state. After the microwave test, the sample is installed for mechanical and permeability tests, and the stress and temperature after the microwave will also be destroyed. Therefore, , this test method cannot truly reflect the actual development of fractures under the in-situ stress state, and the permeability obtained by the test is not the actual permeability of the formation after fracturing and enhancing permeability.

In addition, the existing fracturing experimental devices can usually only conduct a single hydraulic fracturing experiment, which cannot meet the experimental research on shale fracturing and permeability enhancement under the simultaneous action of hydraulic fracturing and microwave fracturing.

One of the difficulties of the permeability testing device and method before and after microwave fracturing considering the actual stress and temperature conditions of the formation is that after microwave, the temperature of the sample increases rapidly with the microwave time and power, and its temperature can reach above 500°C. The maximum temperature resistance of test devices is mostly 150°C. How to effectively shield the high temperature effect generated by microwaves is the key problem faced by in-situ microwave fracturing and permeability enhancement devices.

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