Method and device for measuring pore volume change of porous medium

Abstract

The invention discloses a method and a device for measuring the pore volume change of a porous medium. The method comprises the following steps of: A, putting a workpiece to be tested into a holder; B, closing an upstream control valve and a vent valve, and opening a communication valve, a downstream control valve and a pressure regulating control valve; C, after the device is positioned in the vacuum state and stable, closing the downstream control valve; D, performing confining pressure stepwise loading / unloading experiments; and E, opening the vent valve, setting a pressure regulating controller to be zero, and finishing the measurement of the pore volume change. The pressure regulating controller mainly comprises a front fixing sleeve, a rear fixing sleeve, a movable sleeve, a sliding head, a sliding block, a screw rod, a rotary head and a rotary rod, wherein the rear fixing sleeve is provided with a main scale; the movable sleeve is provided with a branch scale; and the main scale and the branch scale are used for reading the volume difference. The device is easy to operate, is convenient to read, is stable in performance and reliable in measurement, and is suitable for quick, continuous, accurate and intuitive measurement of wide-range pore volume change of porous media under the condition of complicated stress variation.

Description

technical field [0001] The present invention relates to the porosity measurement technology of rock-like porous media materials, more specifically to a method for measuring the pore volume change in porous media, and also to a measuring device for the pore volume change in porous media, which is suitable for large-scale Continuous, rapid, accurate measurement and direct reading of the pore volume of porous media in a wide range under the condition of stress (such as confining pressure stress, temperature stress) changes. Background technique [0002] Porosity is an important property of porous media materials such as pores and fractures. In recent years, due to underground oil and gas storage, CO 2 For the safety evaluation of saline water layer storage and groundwater energy storage projects, it is necessary to study the porosity change law of such engineering reservoirs and caprocks in the process of deformation and failure under cyclic loading, that is, the porosity of p...

AI Technical Summary

Problems solved by technology

At present, the gas method and Pomeranz's law are mostly used to measure the porosity of porous media, and the porosity difference is used to characterize the change in pore volume, and the pore pressure in the traditional test process is basically limited within 1MPa.

This traditional method and device is no longer suitable for the study of the porosity change law of deep-buried reservoirs and cap rocks with low porosity and high pore pressure, and the traditional method is complicated to operate, with large errors and inconvenient readings. The reasons are: 1. This type of engineering reservoir Groundwater seeps in the caprock, and the traditional method using gas as the fluid medium cannot represent the actual situation; 2. The groundwater in the reservoir caprock of this type of engineering is in a state of high pore pressure, and the traditional method has low gas pore pressure, which cannot simulate the real stress 3. Under the action of cyclic loading, the deformation and failure process of this kind of engineering reservoir cap rock is rapid, and the porosity changes in a wide range. The traditional method is complicated to test, the cycle is long, and the measurement range is small. The test results need to go through cumbersome conversion. Direct reading cannot meet the timeliness of the test, resulting in little applicability of the test results

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