Thermodynamic effects of cycling carbon dioxide injectivity in shale reservoirs

Abstract

Carbon dioxide injectivity has always been considered as one of the optimum enhanced recovery techniques, especially in tight reservoirs regarding the feasible mobilization of gas through porous media. To have a better understanding of carbon dioxide injectivity performances, it would be of importance to consider crucial parameters and their effects on the carbon dioxide adsorption and oil recovery factor. In this paper, the profound impact of crucial parameters such as temperature, pressure, carbon dioxide soaking time, and core stimulation on the oil recovery enhancement were investigated. Moreover, the considerable influence of pressure and temperature on the carbon dioxide adsorption capacity storage were performed and analyzed. According to the result of this experiment, temperature increase led to reducing carbon dioxide storage capacity, which has a reverse pattern with oil recovery factor by increasing temperature. When the core samples were unstimulated, the oil recovery factor has higher than stimulated core samples. Furthermore, pressure increase resulted in the carbon dioxide storage capacity enhancement, which has a similar increase pattern with oil recovery factor by increasing pressure. The maximum carbon dioxide storage capacity is 91% and 90% at the pressure of 1500 psi and temperature of 20 °C respectively. Soaking time rising between oil and carbon dioxide led to producing more oil volume.