Measuring system and method of low-speed non-linear seepage parameters

Abstract

The embodiment of the invention provides measuring system and method of low-speed non-linear seepage parameters. The system comprises a power output device, a pressure measuring device and a flow measuring device, wherein the power output device is connected with a first opening of an intermediate container through a pipeline and is used for outputting different drive pressures so as to displace a displacing fluid in the intermediate container to be transmitted to a core of a core holder by the pipeline; the pressure measuring device comprises a pressure gage and a U-shaped pipe pressure gagewhich are respectively connected with a third opening of the core holder through pipelines and is used for measuring the pressure of the third opening of the core holder under different drive pressures; the U-shaped pipe pressure gage can display the level height difference so as to acquire the starting pressure of the core when the drive pressure is reduced to the minimum value, a switching partis in a closed state and the self level is stable; and the flow measuring device is connected with a fourth opening of the core holder through a pipeline and is used for measuring the volume of the displacing fluid seeped from the core under the different pressures of the third opening. The system can accurately measure the pressure, the starting pressure and the fluid volume under the low-speed non-linear seepage conditions.

Description

technical field [0001] The invention relates to the technical field of testing the permeability of porous materials, in particular to a measurement system and method for low-speed nonlinear seepage parameters. Background technique [0002] Low velocity non-linear fluid flow is a special phenomenon when fluid flows in low permeability porous media. This phenomenon widely exists in oil and gas field development engineering, geotechnical engineering, hydraulic engineering and industrial catalysis and other related disciplines. Seepage in low-permeability porous media no longer obeys Darcy's Law. The shape of the characteristic curve of low-speed nonlinear seepage is closely related to fluid type, rock type and fluid saturation; the seepage capacity of fluid in porous media is a continuous function of pressure. figure 1 It is a schematic diagram of a typical nonlinear seepage characteristic curve of a low-permeability porous medium drawn according to the method of the prior ar...

AI Technical Summary

Problems solved by technology

Therefore, the experimental data has high requirements for measurement accuracy, and it is difficult for ordinary pressure and flow measurement equipment to meet the requirements

If you purchase professional experimental equipment, it is generally expensive, the operation process is complicated, and it is easy to be damaged. In the actual use process, it is difficult to show the superiority of such professional equipment

Judging from the published patent document CN200610069507.8 at home and abroad, the measurement method of the quasi-thrust pressure gradient has been relatively perfect, but the "flow velocity-pressure gradient" relationship (ad curve) in the lower pressure range cannot be accurately measured or even cannot be measured. Moreover, there is no measurement method for the threshold pressure (point a) of low-permeability porous media

Therefore, the complete low-velocity nonlinear seepage curve in low-permeability porous media cannot be drawn, which restricts the development of low-velocity nonlinear seepage theory

Images