Date of Award
Master of Science (MS)
CO2 geological sequestration simultaneously combined with water production from deep saline aquifers can effectively address the challenge faced by the modern energy systems for reducing the CO2 emissions and water intensity while providing reliable, affordable, and secure energy. However, little attention has been paid to date in the literature on determining the best CO2 injection strategy for achieving both the optimal water production and the optimal CO2 space storage capacity while maintaining operational safety. This research first establishes three injection-extraction scenarios based on the typical geological parameters of the Junggar Basin in China to analyze the effect of CO2 injection on water extraction and the effect of water extraction on the CO2 storage. The three injection scenarios considered are sole CO2 injection, sole water production, and combined CO2 enhanced water recovery (CO2 - EWR). For the combined CO2 enhanced water recovery scenario, both the co-injection of brine and pre-injection of brine are considered. It is found that in the allowable range of pressure perturbations, pre-injection of brine could result in longer injection time with more CO2 injected and stored. The influence of number of pumping wells is also analyzed. Although increasing the number of wells can enhance the CO2 storage, however having more wells may not be an economically desirable option considering the cost of well drilling; this aspect requires the techno-economic analysis. It can be concluded from this work that the CO2 enhanced water recovery technology can effectively manage the pressure perturbation caused by the CO2 injection as well as the water production while significantly enhancing the CO2 storage capacity, security and water production efficiency; however, the injection strategy is essential to the efficiency of CO2 enhanced water recovery. The well-known multi-phase flow solver TOUGH2/Petrasim is used for the analysis of injection scenarios.
Ramesh Agarwal, David Peters, Swami Karunamoorthy