Thermo-Chemical Models for Silicate Diagenesis, Overpressure and Hydrocarbon Resource Distributions - The Gulf of Mexico Evidence

O-34 THERMO-CHEMICAL MODELS FOR SILICATE DIAGENESIS OVERPRESSURE AND HYDROCARBON MIGRATION – THE GULF OF MEXICO EVIDENCE P.H. NADEAU P.A. BJØRKUM and O. WALDERHAUG 1 Statoil 4035 Stavanger Norway Abstract Over the last 15 years geochemical models for silicate crystal growth have been developed for predicting the impact of clay diagenesis and quartz cementation on porosity/permeability evolution in sedimentary basins (Nadeau et al. 1985; Walderhaug 1994 1996; Oelkers et al. 1996; Bjørkum et al. 1998). These models indicate that precipitation of diagenetic clay minerals at temperatures > 60°C result in severe permeability reductions in shales/mudstones rendering the affected sedimentary sections prone