Magnetic resonance imaging analysis on the in-situ mixing zone of CO2 miscible displacement flows in porous media

Abstract

Experimental investigations of heterogeneous effect on supercritical pressure CO 2 and water flow in sintered porous media AIP Conf.The in-situ mixing zone represents dynamic characteristics of CO 2 miscible displacement flows, which is important for carbon dioxide enhanced oil recovery (CO 2 -EOR) projects. However, the migration characteristics of the in-situ mixing zone under reservoir conditions has been neither well studied nor fully understood. The in-situ mixing zone with the flowing mixture of supercritical CO 2 and n-decane (nC 10 ) was investigated by using a magnetic resonance imaging apparatus at a reservoir condition of 8.5 MPa and 37.8 C in porous media. The experimental results showed that the CO 2 -frontal velocity was larger than the mixing-frontal velocity. The mixing zone length was linearly declined in the miscible displacement process. And the declining rate of the mixing zone length was increased with injection rate. It indicates that the mixing zone length is not constant in a vertically stable CO 2 misible displacement and a volume contraction due to phase behavior effects may occur. Then, an error function based on the convection-dispersion equation was fitted with CO 2 miscible displacement experiments. The error function was well fitted both at a series of fixed core positions and a series of fixed displacement times. Furthermore, the longitudinal dispersion coefficients (K lx and K lt ) and the longitudinal Peclet numbers (Pe d and Pe L ) were quantified from the fitting results. The evolutions of the longitudinal dispersion coefficient were reduced along the displacement time. And the declining rate was increased with injection rate. And with proceeding, the longitudinal dispersion coefficient was tending towards stability and constant. But the evolutions of the longitudinal Peclet numbers were increased along the displacement time. And the increasing rate was increased with injection rate. V C 2014 AIP Publishing LLC.

Dynamic stability characteristics of fluid flow in CO2 miscible displacements in porous media

“…34 In this section, the dynamic stability characteristics, such as the 11 oil-saturation evolution of the in situ mixing zone and the length evolution of the in situ mixing zone, were calculated and analyzed in the miscible displacement processes. 34 In this section, the dynamic stability characteristics, such as the 11 oil-saturation evolution of the in situ mixing zone and the length evolution of the in situ mixing zone, were calculated and analyzed in the miscible displacement processes.…”

“…The volumetric contraction 34 is not obvious in the entire displacement process, which means that the mixture of a CO 2 /nC 10 The volumetric contraction 34 is not obvious in the entire displacement process, which means that the mixture of a CO 2 /nC 10 …”

“…(The minimum miscible conditions for CO 2 /nC 10 system are determined to be 7.79 MPa at 37.8°C. Additionally, Song et al 34 investigated the in situ mixing zone performance of CO 2 miscible displacement flows using MRI. Zhao et al 29,30 proposed a method to calculate the average CO 2 front velocity of CO 2 miscible displacements in porous media using MRI.…”

Simulation and visualization of the displacement between CO2 and formation fluids at pore-scale levels and its application to the recovery of shale gas

“…A summary of the results of the displacement experiments is shown in Table 1. Song et al (2014) also analysed the in situ mixing zone performance of CO 2 -oil miscible displacement flows in a sand pack using MRI. The mixing zone length, CO 2 frontal velocities, longitudinal dispersion coefficient and Peclet number were quantified based on magnetic resonance imaging.…”

“…When CO 2 is injected into a deep geological formation in the liquid or supercritical state, it will cause large volumes of formation fluids such as oil, water (brine) or natural gas to be physically displaced (Kazemifar et al 2016;Wang et al 2013;Zhang et al 2011b). In the CO 2 displacement process, the major concern is the primary CO 2 plume migration, which is closely related to how much CO 2 can be stored in the respective porous subsurface sedimentary formation, the displacement efficiency of the oil/gas and the security of the stored CO 2 (Berg and Ott 2012;Chen and Zhang 2010;Song et al 2014). Therefore, a better understanding of the displacement mechanisms of CO 2 and formation fluids in porous media is essential to assess the CO 2 leakage risks and predict the amount of CO 2 that can be absorbed and the oil/gas production as well.…”