Experimental Measurements of the Diffusion Coefficient and Effective Diffusion Coefficient of CO<sub>2</sub>–Brine under Offshore CO<sub>2</sub> Storage Conditions
Yi Zhang, Wenyu Geng, Mingkun Chen, Xingang Xu, Lanlan Jiang, Yongchen Song
Abstract
In this article, the diffusion of CO 2 in brine and saturated brine cores under offshore storage conditions was simulated by laboratory experiments. The diffusion coefficients of CO 2 to brine under the offshore storage temperature (286.15–303.15 K) and pressure (0.1–5 MPa) were obtained by using the pressure decay method, which are at a range of 0.126 × 10 –9 m 2 /s to 1.730 × 10 –9 m 2 /s. Meanwhile, the effective diffusion coefficients of CO 2 to saturated brine cores are measured through a system with computed tomography (CT) scanning characterization of three Berea cores with permeability from 10 to 100 mD, which are 1.22 × 10 –15 m 2 /s to 4.81 × 10 –15 m 2 /s at a pressure of 4 MPa and temperature of 290.15 K.