Numerical Simulations of Enhanced Gas Recovery at the Załęcze Gas Field in Poland Confirm High CO₂Storage Capacity and Mechanical Integrity

Abstract

-Natural gas from the Załęcze gas field located in the Fore-Sudetic Monocline of the Southern Permian Basin has been produced since November 1973, and continuous gas production led to a decrease in the initial reservoir pressure from 151 bar to about 22 bar until 2010. We investigated a prospective enhanced gas recovery operation at the Załęcze gas field by coupled numerical hydro-mechanical simulations to account for the CO 2 storage capacity, trapping efficiency and mechanical integrity of the reservoir, caprock and regional faults. Dynamic flow simulations carried out indicate a CO 2 storage capacity of 106.6 Mt with a trapping efficiency of about 43% (45.8 Mt CO 2 ) established after 500 years of simulation. Two independent strategies on the assessment of mechanical integrity were followed by two different modeling groups resulting in the implementation of field-to regional-scale hydro-mechanical simulation models. The simulation results based on application of different constitutive laws for the lithological units show deviations of 31% to 93% for the calculated maximum vertical displacements at the reservoir top. Nevertheless, results of both simulation strategies indicate that fault reactivation generating potential leakage pathways from the reservoir to shallower units is very unlikely due to the low fault slip tendency (close to zero) in the Zechstein caprocks. Consequently, our simulation results also emphasise that the supra-and subsaliniferous fault systems at the Załęcze gas field are independent and very likely not hydraulically connected. Based on our simulation results derived from two independent modeling strategies with similar simulation results on fault and caprock integrity, we conclude that the investigated enhanced gas recovery scheme is feasible, with a negligibly low risk of relevant fault reactivation or formation fluid leakage through the Zechstein caprocks.Résumé -Des simulations numériques de récupération assistée de gaz sur un gisement de gaz de Załęcze en Pologne confirment les capacités de stockage de CO 2 élevées et l'intégrité mécanique dudit gisement -Le gaz naturel du gisement de Załęcze, situé dans la structure monoclinale de la région des Sudètes au niveau du Bassin Permien sud, est produit depuis novembre 1973, moyennant quoi la production de gaz continue a donné lieu à une diminution de la pression initiale du réservoir de 151 bar à environ 22 bar en 2010. Nous avons effectué une étude prospective mettant en jeu une opération de récupération de gaz améliorée sur le gisement de gaz de Załęcze par des simulations

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Full‐scale simulation of a nearly depleted gas field in South Africa for carbon utilisation and storage

“…The pseudoisation procedures should accurately represent the reservoir fluids to ensure the compositional effects expected in the reservoir. 48 Table 3 gives the molecular composition and mole fraction of the pseudo-components in the fluid of compartment C1, while the fluid model is shown in Fig. 8.…”

“…PVTi software developed by Schlumberger was used to pseudoise the original gas composition, while the Peng‐Robinson equation was used as the equation of state (EOS). The pseudoisation procedures should accurately represent the reservoir fluids to ensure the compositional effects expected in the reservoir 48 . Table 3 gives the molecular composition and mole fraction of the pseudo‐components in the fluid of compartment C1, while the fluid model is shown in Fig.…”

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

“…The feasibility of CO 2 -EGR has been investigated by many experimental and numerical simulation studies [83,131,132,211,224,[226][227][228][229][230]. Some typical displacement experiments in a variety of temperature and pressure conditions, revealing the mechanism of CO 2 -EGR and providing a guide line for the application of this technology, are summarized in Table 6.…”