Mechanisms of Fluid Migration and CO<sub>2</sub> Storage in Low Permeability Heavy Oil Reservoirs Using High-Pressure Microfluidic CO<sub>2</sub> Flooding Experiment
Lei Li, Jianyang Zheng, Ying Shi, Yuliang Su, Yongmao Hao, Zheng Chen
Abstract
The effective development of low permeability heavy oil reservoirs is crucial for tapping into unconventional resources. High-pressure CO 2 flooding offers numerous benefits, including reducing crude oil viscosity, enhancing oil fluidity, and decreasing interfacial tension, leading to improved heavy oil production. Additionally, CO 2 can be sequestered in the formation, contributing to carbon emission reduction. However, analyzing the migration and storage effects of CO 2 in low permeability heavy oil reservoirs is challenging. In this study, high-pressure and high-temperature (50 MPa,100 °C) microfluidic experiments were designed and carried out, and the CO 2 flooding characteristics and storage efficiency were studied. The distribution of the remaining oil and mechanisms of CO 2 sequestration under various displacement speeds and injection pressures were analyzed. The results demonstrated that CO 2 flooding achieved significantly higher recovery rates compared to high-pressure water flooding, with increments of 13.89, 21.53, and 23.09% at oil displacement pressures of 30, 40, and 50 MPa, respectively. The CO 2 burial efficiency also showed substantial improvements, reaching 23.55, 34.01, and 37.13% under the corresponding conditions. Furthermore, a higher porosity facilitated CO 2 migration, providing more space and migration channels for CO 2 flow. By examining CO 2 –oil interactions, the study elucidated CO 2 migration patterns and burial efficiency under different displacement modes.