Experimental device for ultrasonic detection of shale hydration microcrack propagation characteristics under high-temperature and high-pressure water circulation effect

Abstract

The invention discloses an experimental device for ultrasonic detection of shale hydration micro-crack propagation characteristics under high-temperature and high-pressure water circulation effect. The experimental device is characterized in that the device can integrally monitor and simulate the internal micro-crack propagation condition under the shale core hydration action in a real deep environment in real time, studies the propagation mechanism of the internal micro-crack, and analyzes the influence on the shale permeability and the shale gas recovery efficiency. The device comprises a high-temperature and high-pressure hydration reaction kettle, a variable-temperature water injection circulating device and a mobile ultrasonic detection device, and the high-temperature and high-pressure hydration reaction kettle simulates a hydration action environment in which liquid water circularly flows and is in full contact with a sample under high-temperature and high-pressure conditions; the variable-temperature water injection circulating device is used for accurately controlling factors such as temperature, confining pressure, flow velocity, water injection pressure and water injection time which influence the expansion characteristics of the shale microcracks; and the mobile ultrasonic detection device detects the microcrack propagation condition in the shale core in real time, so that core hydration and crack propagation detection are synchronously carried out. The device is easy to operate and convenient to move, facilitates research on the shale hydration microcrack propagation characteristics under the high-temperature and high-pressure water circulation effect, and has great significance in deep oil and gas exploration and development.

Description

Technical field: [0001] The invention relates to an experimental device for detecting the expansion of shale hydration micro-cracks, in particular to an experimental device for ultrasonically detecting the expansion characteristics of shale hydration micro-cracks under the action of high-temperature and high-pressure water circulation, belonging to the field of deep oil and gas exploration and development. Background technique: [0002] Shale oil and gas reservoirs have the characteristics of low porosity and low permeability, and shale oil and gas wells have almost no natural productivity, and often require reservoir reconstruction to increase oil and gas productivity. Hydraulic fracturing is one of the main methods of shale reservoir reconstruction. Through hydraulic fracturing, the reservoir forms a complex fracture network to increase the production capacity of shale oil and gas. With the continuous improvement of oil and gas exploration and development technology, shale...

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Problems solved by technology

Among them, the surface observation analysis method can only observe the expansion of fractures outside the shale core, but cannot judge and analyze the expansion of micro-cracks inside the shale; the experimental method of measuring shale hydration micro-cracks by nuclear magnetic resonance technology and CT scanning technology needs to be tested in shale cores. After the hydration is completed, the water can only be tested after it is discharged and treated. It is impossible to monitor the fracture expansion in real time and simulate the hydration environment of high temperature and high pressure in deep shale

In addition, the experimental equipment of nuclear magnetic resonance technology and CT scanning technology is expensive and the operation steps are complicated

[0006] (3) The structure of the high-temperature autoclave has great limitations. Ordinary high-temperature autoclaves can only provide a high-temperature and high-pressure environment, but cannot provide an environment where fluids such as liquid water in deep rock formations act, and cannot simulate the real deep formation environment when shale is filled with liquid water. Expansion of internal microcracks

[0007] (4) The current experimental method of shale hydration involves immersing shale core samples under certain conditions for several hours, which is time-consuming and labor-intensive, and cannot meet the requirements for real-time testing of micro-crack propagation in shale samples

[0008] In order to solve the problem that the conventional experimental device for testing shale sample hydration micro-crack expansion cannot simulate the real environment of deep layers, cannot test the shale sample micro-crack expansion in real time, and the time-consuming and labor-intensive problems of the experiment, the present invention relies on high-temperature and high-pressure hydration reaction Kettle, variable temperature water injection circulation device, ultrasonic detection device, invented an experimental device for ultrasonic detection of shale hydration micro-crack expansion characteristics under high-temperature and high-pressure water circulation, and formed a suitable for detection of shale hydration micro-crack expansion under high temperature and high pressure liquid water environment Integrated real-time monitoring experimental device for characteristics

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