Numerical Trend Analysis for Factors Affecting EOR Performance and CO2 Storage in Tight Oil Reservoirs

• Published in: Fuel (Guildford) 2022-05, Vol.316, p.123370, Article 123370
• Main Authors: Syed, Fahad Iqbal, Muther, Temoor, Van, Vuong Pham, Dahaghi, Amirmasoud Kalantari, Negahban, Shahin
• Format: Article
• Language: English
• Subjects: Anthropogenic factors; Carbon dioxide; Carbon sequestration; Climate change; CO2 injection; CO2 storage; Diffusivity; Enhanced oil recovery; Environmental impact; EOR; Fossil fuels; Global warming; Greenhouse effect; Greenhouse gases; Horizontal wells; Hydraulic fracture; Hydraulic fracturing; Injection; Mathematical models; Oil; Oil recovery; Oil reservoirs; Reservoir storage; Reservoirs; Shale Oil Production; Solubility; Tight Reservoir Development; Trapping; Trend analysis; UEOR; Unconventional reservoirs
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2022.123370

•Multiple solvents and hydraulic fracture designs are numerically tested for EOR.•Fracture Permeability and half-length are the most critical hydraulic fracture parameters for EOR.•Diagnostic contour plots for EOR and CO2 storage in tight oil reservoirs are developed. Improved oil recovery from tight oil reservoirs to fulfill the fossil fuel requirements and the CO2 storage to meet the net carbon zero objectives are the two motivations of this work. CO2 is a major anthropogenic greenhouse gas and its emission to our plants’ atmosphere is hazardous, particularly causing global warming. Therefore, its injection in the sub-surface oil-bearing formations not only improves the oil recovery but also reduces the carbon footprint from the planet. In this study, a mechanistic numerical simulation model is built using typical U.S. tight oil reservoir rock and fluid properties. The reservoir model is equipped with a hydraulically fractured single horizontal well that is subjected to multiple sensitivities using the huff-n-puff technique. Detailed CO2 trapping and diffusivity mechanisms at the nanopore scale are discussed that numerically define the CO2 solubility in formation oil and it’s trapping phenomenon into the nanopore spaces. The results show that CO2 injection works predominantly to achieve significant incremental oil recovery. Also, the reservoir with lighter in-situ fluid composition and higher reservoir pressure further enhances the oil recovery due to improved diffusivity and the solubility of CO2 into the reservoir fluid. It is also found that the increased number of huff-n-puff cycles and the incremental CO2 injection volume in each cycle not only enhance the oil recovery performance but likewise help to trap a larger volume of CO2 into a reservoir. A few diagnostic contour plots are also presented in this study to demonstrate the simultaneous effect of multiple hydraulic fracture parameters and the CO2 injection volume for the directional EOR and CO2 trapping performance. The findings of this study can help for a better understanding of designing EOR operations in tight oil reservoirs to achieve both goals concurrently.