A device and method for testing the dynamic permeability of coal and rock in the process of fracturing physical simulation

Abstract

The invention discloses a coal rock dynamic permeability testing device and method in the process of fracturing physical simulation, including a single-interface high-permeability cushion block, a double-interface high-permeability cushion block and a cylindrical sample clamped between the two cushion blocks. The simulated wellbore is arranged along the center of the upper end surface of the cylindrical sample to the body center of the cylindrical sample. The lower hydraulic head and the hydraulic head in the confining pressure cylinder apply axial pressure to the cylindrical sample, and the hydraulic oil conduit injects hydraulic oil into the confining pressure cylinder and then injects hydraulic oil into the cylindrical sample. Confining pressure is applied to the sample, the target fluid flows from the fluid inlet pipe into the single-interface hyperpermeable pad and the columnar sample, the fracturing fluid enters the columnar sample from the fracturing fluid conduit through the fracturing pad and the simulated wellbore, the target fluid and pressure The cleavage liquid flows from the columnar sample to the double-interface hypertonic pad, and flows through the flowmeter through the fluid outlet tube. The dynamic permeability of the columnar sample is calculated by using the flow rate of the fluid outlet tube, the physical parameters of the fluid, and the size of the columnar sample. The invention can test the dynamic permeability of columnar samples in three stages before fracturing, during fracturing and after fracturing.

Description

technical field [0001] The present invention relates to the technical field of coalbed methane development test, in particular to a test device and method for dynamic permeability of coal and rock in the process of fracturing physical simulation Background technique [0002] In the process of coalbed methane exploration and development, the permeability of coal reservoir is the main parameter for the analysis of coalbed methane seepage. At present, the industry generally believes that the permeability of coal reservoir is one of the key factors restricting the success or failure of the development of coalbed methane resources. Because the coal reservoirs in my country generally have the characteristics of low permeability, this seriously restricts the development of my country's coalbed methane industry. Therefore, it is very important to accurately test the permeability of coal rock samples for the formulation of coalbed methane development plan. At present, the industry h...

AI Technical Summary

Problems solved by technology

However, up to now, there is still a lack of more accurate permeability testing devices and methods during the fracturing process of coal reservoirs, and it is impossible to accurately evaluate the permeability during the fracturing process, and it is difficult to accurately evaluate the permeability enhancement process of fracturing and the effectiveness of fracturing. Bad, unable to study the adaptability between fracturing technology and reservoir in the process of reservoir stimulation

Although China's invention application number 201911030419.0 discloses an experimental device for fracturing natural gas hydrate deposits, the device can be used to observe and evaluate the fracturing effects of natural gas hydrate reservoirs under different fracturing conditions, before and after fracturing, but the reactor of the device The cylinder lacks the function of confining pressure loading, and the piston can only exert axial pressure to squeeze the natural gas hydrate, so that the hydrate forms a passive confining pressure at the part in contact with the reactor cylinder, so the confining pressure cannot be actively adjusted according to the characteristics of the reservoir. Many limitations of the device itself make it not suitable for fracturing of solid samples under normal temperature and pressure, and the device can only measure the gas permeability of natural gas hydrate before and after fracturing, and cannot track the fracturing process Changes in the permeability of the sample in the medium, and it is impossible to test the permeability of the sample with liquid

In general, the existing fracturing devices and permeability testing devices cannot realize the simultaneous dynamic monitoring of the sample permeability during the fracturing process under the simulated horizontal and vertical stresses, which restricts the fracturing of coal reservoirs. In-depth study on the mechanism of permeability enhancement

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