The Green River Natural Analogue as A Field Laboratory To Study the Long-term Fate of CO2 in the subsurface

Chemical–mechanical coupling observed for depleted oil reservoirs subjected to long-term CO2-exposure – A case study of the Werkendam natural CO2 analogue field

“…These observations regarding the impact of reactivity and water:rock ratio on mechanical properties, are in line with the results from a chemo-mechanical study performed on the Green River natural CO 2 field, Utah, USA (Busch et al, 2014). Preliminary results for the Navajo Sandstone showed slight differences in rock strength between the unreacted and CO 2 -exposed material.…”

“…We illustrated the potential effect cement removal due to CO 2 -exposure can have on rock strength for each of the three different cases of cement distribution. The C 0 -data obtained for sandstones from two natural analogue fields, the Röt Fringe Sandstone (this study) and Navajo Sandstone (Busch et al, 2014), are shown as well.…”

CO2‐induced chemo‐mechanical alteration in reservoir rocks assessed via batch reaction experiments and scratch testing

“…Long‐term exposure to CO 2 ‐brine mixtures at natural CO 2 accumulations has resulted in alteration of mechanical properties including: strengthening in Navajo Sandstone, sandstones of the Salt Wash Member of the Morrison Formation and Mancos Shale, and weakening in Entrada Sandstone, Summerville Siltstone, and portions of the Röt Fringe Sandstone . Despite bulk mechanical alterations triggered by naturally occurring CO 2 , the sliding friction coefficient of some sandstones exhibit negligible changes upon mineral dissolution and precipitation …”

“…[4][5][6] Long-term exposure to CO 2 -brine mixtures at natural CO 2 accumulations has resulted in alteration of mechanical properties including: strengthening in Navajo Sandstone, sandstones of the Salt Wash Member of the Morrison Formation and Mancos Shale, and weakening in Entrada Sandstone, Summerville Siltstone, and portions of the Röt Fringe Sandstone. [7][8][9] Despite bulk mechanical alterations triggered by naturally occurring CO 2 , the sliding friction coefficient of some sandstones exhibit negligible changes upon mineral dissolution and precipitation. 9,10 Alteration of rocks with CO 2 -brine in the laboratory also results in measurable changes in geomechanical and transport properties, such as increased permeability and porosity, 11 dissolution of siliceous and carbonate minerals, 12 reduction of indentation stiffness, 13,14 reduction of fracture toughness, 7 and decrease of the size of yield stress locus.…”

“…[7][8][9] Despite bulk mechanical alterations triggered by naturally occurring CO 2 , the sliding friction coefficient of some sandstones exhibit negligible changes upon mineral dissolution and precipitation. 9,10 Alteration of rocks with CO 2 -brine in the laboratory also results in measurable changes in geomechanical and transport properties, such as increased permeability and porosity, 11 dissolution of siliceous and carbonate minerals, 12 reduction of indentation stiffness, 13,14 reduction of fracture toughness, 7 and decrease of the size of yield stress locus. 15 Changes are more impactful in rocks with load-bearing dissolvable minerals or clay cements sensitive to pore-fluid chemistry.…”