--> Abstract: Thermo-Kinetic Modeling of the Mass Exchange Mechanisms Between Water-Rock-Gas Induced by Acid Gas Injection in Carbonate Reservoirs, by Mohamed Azaroual, J.-C. Lacharpagne, E. Caroli, and Isabelle Czernichowski-Lauriol; #90039 (2005)

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Thermo-Kinetic Modeling of the Mass Exchange Mechanisms Between Water-Rock-Gas Induced by Acid Gas Injection in Carbonate Reservoirs

Mohamed Azaroual1, J.-C. Lacharpagne2, E. Caroli2, and Isabelle Czernichowski-Lauriol1
1 Bureau de Recherches Geologiques et Minieres (BRGM), Orleans, France
2 TOTAL, Pau, France

Several industrial operations of acid gas injection (H2S – CO2) in deep geological systems are planned to be developed in various contexts. These industrial practices may induce modifications of the mineralogical and petrophysical properties of the host rock. Consequently, one will be able to predict the behaviour of target rocks in order to ensure the integrity of the reservoirs and the permanence of the sequestration. To understand the induced physical chemical mechanisms by such acid gas injections, an analysis of the rich natural systems in acid gas as well as thermo-kinetic numerical simulations were carried out. The acid gas origin (H2S and CO2) and their generation in carbonate reservoir is examined in order to characterise their geochemical cycles in the sedimentary carbonated reservoirs. Next, the calculations of the thermodynamic equilibrium allowed to examine the stable mineralogical assemblies in saline waters with high partial pressures of H2S and CO2. On the other hand, for the H2S rich systems, the problem of the role of unstable dissolved sulfur species in the kinetic of the precipitation reactions complicating numerical modelling is analysed and discussed. Most of the modelling tests result in the integration of the elemental sulfur (S°) in the reaction path based on the main reactions of the carbonated reservoirs subject to the acid gas injection conditions (50% H2S + 50% CO2) at 200 bars and 100°C.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005