Performance of CO2-EOR and Storage Processes Under Uncertainty

Abstract

This paper presents an optimization approach using a reservoir field scale compositional flow model to co-optimize oil production and CO2 storage performance in the Farnsworth field unit (FWU), Ochiltree County, Texas. A geocellular model constructed from geophysical geological and engineering data acquired from the unit was used for the study. An initial history match of primary and secondary recovery constructed was used as basis for CO2 flood study. A scenario based prediction model constructed for FWU (Ampomah et al. 2016a) was used as the baseline case for comparison to study the effect of recycling produced gas, infill drilling and water alternating gas (WAG) cycles on oil recovery and CO2 storage. A multi objective function that considers both oil recovery and CO2 storage was defined. Initial sensitivity analysis using a Latin-hypercube sampling technique was used to study the effects of operational uncertain variables on a defined objective function. A number of these operational variables were selected as control variables to be included in the optimization process. A neural network optimization algorithm was utilized to optimize the objective function both with and without uncertainty. Vertical permeability anisotropy ratio (Kv/Kh) was selected as the uncertain parameter in optimization, with uncertainty based on experience from the history match. A risk aversion factor was used to represent results at various confidence levels. The simulation results were compared to a baseline case that predicted a CO2 storage of 75% purchased CO2 and oil recovery of 72% original oil in place. The results showed an improved approach for optimizing oil recovery and CO2 storage within FWU. At the end of 21 years of prediction out of the optimal case, more than 94% of purchased CO2 has been stored and nearly 80% of the oil recovered. The sensitivity analysis reduced the number of control variables to lessen computational time. The defined objective function proved to be a robust approach to co-optimize oil recovery and CO2 storage. The Farnsworth CO2 project will serve as a benchmark for future CO2–EOR or CCUS projects in the Anadarko basin or geologically similar basins throughout the world.

A Review of CO2 Storage in View of Safety and Cost-Effectiveness

“…To co-optimize the CO2 storage and enhanced oil recovery, Ampomah et al [218] proposed an objective function (Equation (6)) considering both CO2 storage and oil production, which can be optimized by the neural network and genetic algorithm. In the optimal case of the Farnsworth field The first CO 2 -EOR pilot project was implemented at the SACROC oil field in 1972 [206], in which CO 2 foam was implemented to alter the mobility and improve the sweep efficiency [207,208].…”

“…To co-optimize the CO 2 storage and enhanced oil recovery, Ampomah et al [218] proposed an objective function (Equation (6)) considering both CO 2 storage and oil production, which can be optimized by the neural network and genetic algorithm. In the optimal case of the Farnsworth field unit, more than 94% of CO 2 could be sequestrated with approximately 80% of the oil produced, which provides a guideline for the co-optimization of CO 2 storage and EOR.…”

Control of Cement Timing, Mineralogy, and Texture on Hydro-chemo-mechanical Coupling from CO2 Injection into Sandstone: A Synthesis

“…Understanding the robustness of CO 2 storage sites is critical for research scientists and industry regulators when selecting injection formations. The Morrow B sandstone in the Farnsworth Unit, TX, was actively utilized for petroleum production and is currently a CO 2 -EOR demonstration site with the Southwest Energies 2023, 16, 7949 2 of 27 Partnership project and is supported by the Department of Energy [3,4,[14][15][16][17][18]. Specifically, HCM experiments associated with the SWP project were focused on the multiphysics within carbonate-cemented sandstone in a single fluid phase at the core scale.…”

Advancing Enhanced Oil Recovery as a Sequestration Asset

“…Here, we use generalized results of prior studies of co-optimized CO 2 EOR plus sequestration. [5][6][7][8][9][10][11][12] For illustration, we focus on the hypothetical oil field described in Table 1 with 180 million barrels OIP. After primary and secondary production, we consider two cases: conventional CO 2 EOR and A-CO 2 EOR.…”