Cross-correlation method for measuring the stress sensitivity of ultra-low permeability rock permeability

Abstract

The invention provides a mutual correlation technology for measuring permeability stress sensitivity of ultra-low permeability rocks. The technology comprises the following steps: a) an ultra-low permeability rock core of shale or tight sand rock and the like is selected, and processed into a cylindrical sample; b) a cylindrical steel block standard sample is processed for system calibration; c) the measurement of ultra-low permeability is carried out through a periodic oscillation method, the pore medium can employ gas or water, and the measurement result of the steel block is used for calibrating the system; d) the rock core is placed in a clamp holder, and applied with confining pressure and pore pressure, the rock core is saturated, An upstream sine pressure wave is applied and kept constant, the responses of the downstream pressure waves at different confining pressures are measured; e) the downstream pressure waves at different confining pressures are subjected to mutual correlation analysis, the change of permeability with confining pressure is obtained. Combined with a periodic oscillation method for measurement of permeability of ultra-low permeability rocks, pressure waveforms for measurement of permeability are subjected to mutual correlation analysis, the precision of measurement of permeability change is raised, and the problem of measurement of ultra-low permeability stress sensitivity is solved.

Description

technical field [0001] The invention relates to a method for testing the stress sensitivity of ultra-low permeability materials, in particular to a cross-correlation test method for measuring the stress sensitivity of ultra-low permeability rock permeability. The invention can provide method support for the permeability stress sensitivity test of unconventional oil and gas reservoirs and nuclear waste reservoirs. Background technique [0002] Permeability is the most important physical parameter of reservoir and the basis of oil and gas development. In recent years, with the development of unconventional oil and gas such as shale gas and tight sandstone oil and gas, it is urgent to develop ultra-low permeability (<0.1×10 -3 μm 2 ) testing, which poses challenges to both testing methods and instruments, and is a difficult point in unconventional oil and gas development research. At present, the steady-state method and pulse decay method are mainly used in my country's p...

AI Technical Summary

Problems solved by technology

Otherwise, small temperature and environmental disturbances may cause the pore pressure curve to be difficult to fit

Currently commonly used steady-state method and pulse decay method to measure ultra-low permeability are not stable enough, and the accuracy is also affected by temperature noise, etc., making it more difficult to measure the stress sensitivity of permeability

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