Profitability Evaluation of a Hybrid Geothermal and CO2 Sequestration Project for a Coastal Hot Saline Aquifer.

¹ Department of Chemical and Petroleum Engineering Schulic School of Engineering University of Calgary END 204E 2500 University Drive NW, Calgary, AB T2N 1N4 T: 403.220.5652 tatyana.plaksina@ucalgary.ca
² Department of Chemical and Petroleum Engineering Schulich School of Engineering University of Calgary 2500 University Drive NW, Calgary, AB T2N 1N4 kanfar@gmail.com

Abstract

With growing interest in commercial projects involving industrial volume CO₂ sequestration, a concern about proper containment and control over the gas plume becomes particularly prominent. In this study, we explore the potential of using a typical coastal geopressured hot saline aquifer for two commercial purposes. The first purpose is to harvest geothermal heat of the aquifer for electricity generation and/or direct use and the second one is to utilize the same rock volume for safe and controlled CO₂ sequestration without interruption of heat production. To achieve these goals, we devised and economically evaluated a scheme that recovers operational and capital costs within first 4 years and yields positive internal rate of return of about 15% at the end of the operations. Using our strategic design of well placement and operational scheduling, we were able to achieve in our numerical simulation study the following results. First, the hot water production rates allowed to run a 30 MW organic Rankine cycle plant for 20 years. Second, during the last 10 years of operation we managed to inject into the same reservoir (volume of 0.8 x 10₉ m₃) approximately 10 million ton of the supercritical gas. Third, decades of numerical monitoring the plume after the end of the operations showed that this large volume of CO₂ is securely sequestrated inside the reservoir without compromising the caprock integrity.