Simulation of mineral diagenesis in reservoirs. Application to illite formation in feldspathic sandstones

摘要: Petroleum geologists and production engineers are faced with reservoirs where porosities permeabilities (poroperm) have been reduced by mineral phases precipitated during the geological evolution. Diagenesis of sandstones is influenced many factors : initial composition sediment, burial history, infiltrated waters. An appraisal poroperm decline due to diagenesis only can result from an integration these factors. A quantitative evaluation diagenetic phenomena possible using numerical modelling. first approach transformations be made a new geochemical modelling software (NEWKIN) applied closed cells, aqueous solution minerals not in equilibrium initially. Cements illite quartz frequently occur bearing feldspar, such as Middle Jurassic Brent Group (East Shetland Basin, North Sea) which today lie between 3500 4500 depth. Results cells simulations presented, explore conditions silica authigenesis this Province, particularly terms temperature, water composition, kinetics (oversaturation waters respect quartz, low pH). Another key non-equilibrium, pervious rocks, flow interstitial water. Its role must appraised -[open quotes]reaction-transport[close quotes]more » code. presented (DIAPHORE), able solve, at reservoir scale, coupled way (1) advection chemical elements porous volume; (2) mass balance considered rock (3) dissolution-precipitation occurring locally (using code precedently described); (4) feedback on permeability reactive surface areas through [open quotes]textural[close quotes] model grain scale.« less