|Publisher||Society of Petroleum Engineers||Language||English|
|Content Type||Conference Paper|
|Title||Optimization of Geologic CO2 Storage in Heterogeneous Aquifers through Improved Sweep Efficiency|
H. Shamshiri, SPE, B. Jafarpour, SPE, Texas A&M University
SPE International Conference on CO2 Capture, Storage, and Utilization, 10-12 November 2010, New Orleans, Louisiana, USA
2010. Society of Petroleum Engineers
|6.8 Fundamental Research in Reservoir Description and Dynamics
Optimization of waterflooding sweep efficiency has been widely applied in reservoir engineering to improve hydrocarbon recovery while delaying water breakthrough and minimizing the bypassed oil in reservoirs. We develop a new framework to optimize flooding sweep efficiency in geologic formations with heterogeneous properties and demonstrate its application to waterflooding and geological CO2 sequestration problems. The new method focuses on equalizing and delaying (under constant total injected volume) the breakthrough time of the injected fluid at production wells. For application to CO2 sequestration where producers may not be present, we introduce the concept of pseudo production wells that have insignificant production rates (with negligible effect on the overall flow regime) for quantification of hypothetical breakthrough curves that can be used for optimization purpose. We apply the new method to waterflooding and CO2 sequestration optimization using two heterogeneous reservoir models. We show that in water flooding experiments the proposed method improves the sweep efficiency by delaying the field breakthrough and equalizing breakthrough times in all production wells. In this case, the optimization results in increased oil recovery and decreased water production. We apply a modified version of the proposed algorithm to geologic CO2 sequestration problems to maximize the storage capacity of aquifers by enhancing the residual and dissolution trapping. The results from applying the proposed approach to optimization of geologic CO2 storage problems illustrate the effectiveness of the algorithm in improving residual and solubility trapping by increasing the contact between available fresh brine and the injected CO2 plume through a more uniform distribution of CO2 in the aquifer.
The pressing need for a clean and renewable energy infrastructure is primarily driven by the worldwide depletion of easily recoverable fossil fuel resources and the alarming trends in climate change and environmental degradation. According to the United Nations Intergovernmental Panel for Climate Change (IPCC, 2005), today, approximately 80% of the global energy consumption is supplied by fossil fuels, a fact that does not seem to change for the near future. The existing evidence suggests that the move toward clean and sustainable energy resources is likely to be fueled mainly by carbon-based fossil energy sources, which has called for controlled emission of anthropogenic carbon dioxide (CO2) into the atmosphere (IPCC, 2005). In the portfolio of climate change mitigation actions, CO2 capture and storage (CCS) has been considered as one of the viable options for reducing, primarily large point-source, emissions of anthropogenic CO2 into the atmosphere (IPCC, 2005). Compatibility of CCS systems with current energy infrastructures, together with its potential to reduce CO2 emissions over the next century, explains the strong interest in this technology. In addition, while the published storage needs for stabilizing CO2 concentration at a safe level vary over a wide range (220-2,200GtCO2), the IPCC report estimates that the technical potential for worldwide geologic storage alone is sufficient to cover the high end of the economic potential range (IPCC, 2005).
|File Size||2,220 KB||21|