Field‐scale reactive transport assessment of CO₂ storage in the Farnsworth unit through enhanced oil recovery practices

Abstract

The objective of this study was to investigate the transport and fate of CO2 injected into a sandstone reservoir in the western Farnsworth Unit, a hydrocarbon field in northern Texas. The study employed three‐dimensional multifluid‐phase numerical reactive solute and heat transport modeling. Model inputs were obtained from previous field characterization studies and calibrated to 8 years of historical production data. The CO2 in the models was injected through multiple wells for the first 25 years of the simulations according to a water‐alternating gas schedule. The simulations were carried out for a total of 1000 years in order to study the long‐term effects of CO2 injection. The results show that the largest fraction of the injected CO2 is stored in oil, followed by successively smaller amounts in the formation water, carbonate mineral phases, and as an immiscible gas phase. The small fraction of CO2 present as an immiscible gas, the most mobile phase for CO2, aids in the long‐term sequestration security of the injected CO2. The injected CO2 was found to migrate within a maximum radius of around 500 m of the injection wells. This means that changes in fluid pressure, temperature, composition, and reservoir mineralogy were also limited to occurring within this radius. This radius is very sensitive to model relative permeability and capillary pressure values, which were determined from history matching to the field production data. The models predicted dolomite to be the main mineral sink for the injected CO2. Quartz was another mineral predicted to precipitate, whereas calcite, albite, chlorite, illite, and kaolinite were predicted to dissolve. The changes in mineral abundance had minimal effect on porosity, implying that the permeability of the reservoir should also not change much because of CO2 injection. © 2023 Society of Chemical Industry and John Wiley & Sons, Ltd.

Investigation of the Effect of Injected CO2 on the Morrow B Sandstone through Laboratory Batch Reaction Experiments: Implications for CO2 Sequestration in the Farnsworth Unit, Northern Texas, USA

“…The SEM analyses showed this precipitate likely to consist mainly of silica and dolomite. This result is generally consistent with the numerical reactive transport model results described in Kutsienyo et al [15] and Kutsienyo et al [6]. The experimental results are also consistent with the reaction path model results in the present study: the reaction path model results predict a steady increase in dolomite abundance over time, though the amount of silica precipitated in the reaction path models is too small to alter the proportional abundance of quartz significantly.…”

“…Little change in the proportion of pore space to mineral matrix (i.e., in porosity) over time is discernible. This is likely in part a function of the short experimental durations, which did not provide much time for mineral precipitation or dissolution, but is also consistent with the numerical modeling results of Kutsienyo et al [6,15] which predicted minimal changes in reservoir porosity because of CO2 injection over time scales of up to 1000 years.…”

“…The experimental results are also consistent with the reaction path model results in the present study: the reaction path model results predict a steady increase in dolomite abundance over time, though the amount of silica precipitated in the reaction path models is too small to alter the proportional abundance of quartz significantly. Other modeling studies by Ahmmed et al [4], Pan et al [10], Khan [11], Kutsienyo et al [12], Sun et al [13], Kutsienyo et al [15], Gyamfi et al [8], and Kutsienyo et al [6] consistently predicted silica to precipitate (as quartz) as well, and Khan [11] also predicted dolomite to precipitate. The experimental results are important because they demonstrate the intrinsic state of silica saturation of the Morrow B formation water and the importance of dolomite as a mineral sink for CO 2 , as predicted from the theoretical models.…”

“…The investigation has been conducted by the Southwest Partnership for CO 2 Sequestration (SWP), one of seven regional CO 2 sequestration partnerships initiated and funded by the U.S. Department of Energy. Much of the investigation of the FWU by the SWP has focused on numerical modeling of the physical and chemical behavior of the injected CO 2 [4][5][6][7][8][9][10][11][12][13][14][15][16]. These models have made some important predictions about the fate of the injected CO 2 , including how the injected CO 2 is partitioned among water, oil, gas, and mineral phases, how far and how quickly the injected CO 2 will migrate from its sources, how hydrocarbon production will be affected, and how the hydraulic properties of the reservoir will be changed.…”