Variable flow pressure and constant confining pressure permeability stress sensitivity combined measurement device and method for multiple cores

Abstract

The invention discloses a multi-core variable flow pressure and constant confining pressure permeability stress sensitivity combined measurement device and method. The device comprises N + 1 standard containers, valves, pressure sensors, N + 1 core holders, an ISCO pump and a calculation device. The core holder is used for clamping a plunger sample core to be tested; the ISCO pump is used for applying confining pressure to the core holder; the standard container is used for containing high-pressure gas, and in the experiment process, the high-pressure gas is filled into the core holder by opening the valve; the pressure sensor is used for metering confining pressure and pressure at two ends of the core holder; the calculating device is used for calculating the core permeability and effective stress of the N plunger samples to be measured under different flow pressures according to the confining pressure, the pressure balance duration time under different pressure measuring points and the pressure at the two ends of the core holder. The method is low in hardware requirement, simple to operate and high in measurement precision.

Description

technical field [0001] The invention relates to the technical field of core experiment analysis for oil and gas field development, in particular to a device and method for stress-sensitive joint measurement of variable flow pressure and constant confining pressure of multiple cores. Background technique [0002] This section is intended to provide a background or context to the embodiments of the invention recited in the claims. The descriptions herein are not admitted to be prior art by inclusion in this section. [0003] With the development of the gas reservoir, the pressure of the gas reservoir is getting lower and lower, the effective stress is getting bigger and bigger, the pores of the reservoir are compressed, and the permeability is reduced, showing the characteristics of permeability stress sensitivity. An important factor to be considered in development and productivity evaluation, especially for high-pressure gas reservoirs, the effective stress changes in a wid...

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Problems solved by technology

The conventional method has the following three disadvantages: 1) The pressure of the overlying strata on the actual reservoir remains unchanged, and the flow pressure drops, so the pressure change process of the constant flow pressure and variable confining pressure experiment is inconsistent with the actual reservoir pressure change process; 2) The constant confining pressure . The outlet of the variable flow pressure experiment needs a high-precision back pressure valve to add back pressure to maintain a large pressure and a small pressure difference. The cost of the experiment is high; 3) Only one piece can be tested at a time, and the test speed is relatively slow, which cannot meet the stress sensitivity of tight core permeability. Extensive testing requirements

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