Experimental device for simulating CO2 in dense matrix-crack diffusion and front edge prediction method of experimental device

Abstract

The invention discloses an experimental device for simulating CO2 in dense matrix-crack diffusion and a front edge prediction method of the experimental device. On the basis of the prior art, the experimental device is improved, cracks are simulated by a fracturing proppant compacting strip, and a transverse injection mode (if the injection is vertical, the pressure in the injection process may impact the matrix section, crude oil near the matrix section is caused to be squeezed into the deep part of the matrix, so that the diffusion experiment precision is affected) is adopted, the latent period effect caused by the pressure impact effect during gas injection is reduced, and the experimental determination of a diffusion coefficient is enabled to be more accurate. The improved device is easy to operate and can simulate the real environment better; and meanwhile, a experimental model is used for predicting the CO2 concentration field and diffusion front edge, the interference to the system balance caused by direct sampling to obtain CO2 concentration in the diffusion process is avoided, and the experimental accuracy is improved.

Description

technical field [0001] The invention relates to the technical field of oil and gas field development engineering, in particular to an experimental device for simulating the diffusion of CO2 in tight matrix-fractures and a front edge prediction method. Background technique [0002] CO 2 Diffusion and dissolution in crude oil can reduce the viscosity and interfacial tension of crude oil, extract light components in crude oil and expand the volume of crude oil, thereby improving the fluidity of crude oil and improving oil recovery. in CO 2 - Molecular diffusion plays an extremely important role in the EOR process, CO 2 The diffusion coefficient in crude oil determines its dissolution rate and final dissolved amount in crude oil, which in turn affects the effect of enhanced oil recovery. [0003] The development of tight oil reservoirs is very important to alleviate the tension between the supply and demand of my country's oil resources. However, due to the characteristics of...

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Problems solved by technology

On the other hand, for CO 2 The research on the concentration field and the diffusion front in the diffusion process, at present, mainly obtains CO directly through chromatographic analysis after sampling along the process. 2 Concentration value, but sampling will disturb the balance of the system and affect the accuracy of the experiment; and there are few studies on the diffusion front

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