Method for measuring diffusion coefficient of carbon dioxide in saturated oil core

Abstract

The invention relates to a method for measuring a diffusion coefficient of carbon dioxide in a saturated oil core. The method comprises the following steps of: performing nondimensionalization by using a convection-diffusion mathematical model, and performing numerical solution, wherein the diffusion coefficient Deff of the carbon dioxide in the saturated oil core is finally obtained by using the method and required to be used in the numerical solution process; and continuously correcting the value of D'eff, and repeatedly executing the step (13), so a curve c of delta Co and t<1 / 2> is completely coincided with a curve b of delta PTh and the t<1 / 2>, wherein the D'eff is the Deff and represents the diffusion coefficient of the carbon dioxide in the saturated oil core. The method has the advantages that the influence of the volumetric expansion of crude oil caused by dissolution of the carbon dioxide in the crude oil on the diffusion process and the influence of a porous medium on the diffusion process are taken into consideration, and the obtained effective diffusion coefficient of the carbon dioxide in the saturated oil core can accurately reflect the true diffusion process.

Description

technical field [0001] The invention relates to a method for measuring the diffusion coefficient of carbon dioxide in saturated oil cores, belonging to the technical field of petrochemical industry. Background technique [0002] The problem of global warming caused by the massive emission of carbon dioxide is becoming more and more severe. Carbon dioxide capture and storage (CO 2 Capture and Storage) technology has been widely considered as a potential and alternative carbon dioxide emission reduction solution, which can reduce the carbon dioxide content in the atmosphere and alleviate the problem of climate warming. In CO2 geological storage schemes, enhanced oil recovery with CO2 (CO2 2 -EOR), not only can achieve the sequestration effect of carbon dioxide, but also can enhance the oil recovery of oil reservoirs, so carbon dioxide enhanced oil recovery technology is widely used in oil fields. In the process of carbon dioxide flooding, the mass transfer law of carbon di...

AI Technical Summary

Problems solved by technology

[0003] The current method for measuring the diffusion coefficient of carbon dioxide in porous media is mainly the PVT method of non-expansion diffusion, which only considers the diffusion of carbon dioxide in porous media, and does not consider the influence of the volume expansion of crude oil on diffusion due to the dissolution of carbon dioxide. Good simulation of the real diffusion process of carbon dioxide in saturated crude oil core

At the same time, the PVT method is currently used to measure the diffusion coefficient of carbon dioxide in crude oil. The measurement of this diffusion coefficient does not reflect the influence of porous media on the diffusion process, so it cannot be used to measure the diffusion coefficient of carbon dioxide in saturated crude oil cores.

Images