Advanced Reservoir Characterization for CO2 Storage

Abstract

Abstract Injection of CO2 into the subsurface is of interest for CO2 storage and enhanced oil recovery (EOR). There are, however, major unresolved questions around the multiphase flow physics and reactive processes that will take place after CO2 is injected, particularly in carbonate rock reservoirs. For example, the wetting properties of CO2-brine-rock systems will impact the efficiency of EOR operations and CO2 storage but reported contact angles range widely from strongly water-wet to intermediate wet. Similar uncertainties exist for properties including the relative permeability and the impact of chemical reaction on flow. In this presentation we present initial results from laboratory studies investigating the physics of multiphase flow and reactive transport for CO2-brine systems. We use traditional and novel core flooding techniques and x-ray imaging to resolve uncertainties around the CO2-brine contact angle, relative permeability, residual trapping, and feedbacks between chemical reaction and flow in carbonate rocks. Introduction Uncertainty around CO2 storage and EOR may be significantly reduced from a greater understanding of the fundamental physics of fluid flow and reactive transport that control rock-brine-CO2 interaction in the subsurface. The combination of unique multiphase flow properties and significant reactivity in the CO2-brine-carbonate rock system has major impacts on the injection, flow and immobilization of CO2 in the subsurface. These unique properties must be accurately characterized to reduce major uncertainties for CO2 storage and EOR in carbonate rocks. Observations of reservoir condition multiphase flow and reactive transport properties for the CO2-brine-carbonate rock system are provided including wetting properties, capillary pressure, relative permeability and residual trapping. A methodology is presented for utilizing a combination of novel and traditional core-flooding and imaging techniques for a comprehensive characterization of carbonate reservoir rock.