Impact of Grain-Coating Clays on Porosity Preservation in Paleocene Turbidite Channel Sandstones: Nelson Oil Field, UK Central North Sea

The Forties Sandstone Member is an important deep-water reservoir in the Central North Sea. role of depositional characteristics, grain-coating clays, and diagenesis controlling quality sandstones poorly understood. main aim study to understand pore-filling evolution turbidite-channel sandstones. employed a multi-disciplinary technique involving thin section petrography scanning electron microscopy (SEM) investigate impact grain size, clay matrix content, mode occurrence chlorite illite, their arresting quartz cementation overall Results our reveal that porosity has been influenced by both primary characteristics diagenesis. Sandstones with coarser size lower content have best (up 28%) compared those finer higher content. Quartz cement volume decreases increasing clay-coating coverage. Clay coating coverage >40% effective cementation. Total as low 10% could deleterious on quality. potentially be suitable candidate for physical mineralogical storage CO2. However, because its high proportion (>20%) chemically unstable minerals (feldspar, carbonates, clays), dissolution due CO2 injection increase permeability order magnitude, thereby affecting geomechanical tensile strength Therefore, experimental investigating amount injected (and at what pressure) required maintain preserve borehole integrity. findings can applied other reservoirs similar environments improve prediction.