Organic - inorganic interactions between shale and sandstone and its effect on reservoir properties: a case study from the Campine basin (NE-Belgium)

Organic-inorganic interactions, which refer to the reactions that participate in alteration processes in sandstone reservoirs, have been studied in sedimentary basins for many years. These organic-inorganic interactions create or destroy the porosity and permeability of sandstone reservoirs. In this project, we will sample comparable sedimentary successions with sandstone/shale and sandstone/coal relationships that have been buried at different depth and by looking to inorganic and organic parameters to deduce which diagenetical processes that played a role in these tight sandstones. The aims of this project are (1) to investigate inorganic-organic interactions in Westphalian A & B sandstone systems and related clay/coal interlayers with sandstones that underwent different burial depths and that consist of different mineralogies, (2) to evaluate their consequences on reservoir alteration. Conducting this study has far-reaching implications for successful reservoir prediction and engineering. Formation of pore-filling minerals, such as kaolinite, dickite and/or calcite, ankerite could significantly deteriorate reservoir quality by both reducing porosity and permeability of rocks for oil/gas recovery, or for the use of these reservoirs for geothermy or CCS. In contrast, dissolution of feldspar and carbonate may produce secondary porosity that could greatly improve reservoir quality.