Evaluation of the geochemical impact of biomethane and natural gas mix injection in sandstone aquifer storage. - Géosciences (GEOSCIENCES) Accéder directement au contenu
Poster De Conférence Année : 2023

Evaluation of the geochemical impact of biomethane and natural gas mix injection in sandstone aquifer storage.

Camille Banc
Irina Sin
Laurent de Windt
Anelia Petit
  • Fonction : Auteur

Résumé

EU is seeking to rapidly replace part of the natural gas usually stored in deep saline aquifers by its renewable analogue, i.e. biomethane. While natural gas is depleted in oxygen, up to 10 000 ppm of O2 can be measured in biomethane. But to date, the geochemical impact of the injection of a gas mix containing natural gas (thus CH4 and CO2) and biomethane (thus oxygen) in deep saline aquifer has never been studied. The objective of this study is to evaluate the resilience of geological storage to oxygen injection and predict the evolution of the quality of the formation water, the gas plume and the rock formation. To do so, multiple injection scenarios with various gas quality were tested using multiphase reactive transport modeling. The gas mixtures were injected in two different deep saline aquifers in the Paris Basin (France) whose petrophysical and geochemical characteristics were reproduced during the simulation. Site 1 was a felspathic sandstone with clay cement and site 2 was a sandstone with clay-calcareous cement. One dimensional radial flow model evidenced that in both sandstones, the injection of gas mix induced an acidification of the solution from pH~8 to pH~6. The injected oxygen originating from biomethane was quickly consumed during pyrite oxidation and contributed to the acidification of the formation water close to the injection point. However, the injection of 1% mol fraction of CO2(g) contained in the gas mix was the main acidification factor. Model demonstrated that the sandstones pH buffering capacity relied upon three geochemical processes (i) calcite dissolution, (ii) feldspar dissolution and (iii) clays dissolution and sorption capacity. These three pH-buffers were efficient for oxygen contents from 10 to 1000 ppm. Models predicted that the gas mix injection could induce minimal but long-term change in the nature of mineral phases but without significantly impacting the porosity. Overall, the gas quality was preserved in both sandstones. This result was evidenced with the modeling of entire gas injection and withdrawal scenario. CO2(g) exsolution, and to a lesser extent H2S(g) exsolution, could occur during these cycles. In addition, this study through modeling results concluded that the injection of biomethane did not significantly change gas-water-rocks interactions compared to those of natural gas injection. This study also evidenced that the detailed results were largely site-dependent.
Fichier principal
Vignette du fichier
PDFsam_merge.pdf (1.95 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-04077902 , version 1 (21-04-2023)

Identifiants

Citer

Camille Banc, Irina Sin, Laurent de Windt, Anelia Petit. Evaluation of the geochemical impact of biomethane and natural gas mix injection in sandstone aquifer storage.. EGU2023, Apr 2023, Vienne (AUT), France. 2023, ⟨10.5194/egusphere-egu23-17538⟩. ⟨hal-04077902⟩
36 Consultations
19 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More