Mineral-fluid buffering during burial diagenesis

Background

Analyses of subsurface water and gas samples from sedimentary basins, have shown an increasing concentration trend of gases like CO2 and H2S with depth. This indicate that specific mineral-fluid reactions can buffer the system.

Mineral –fluid buffering in hydrothermal systems observed in volcanic regions (Iceland, New Zealand, Japan, Italy etc) is well established and characterized 50-30 years ago, but gas concentrations in oil-prone sedimentary basins behave differently. The MSc project will, by geochemical model calculations, explore how different sediment mineralogy and fluid composition can buffer the amount of CO2, H2S and other gases with increasing burial temperature and pressure.

Knowledge about diagenetic mineral reactions from the Norwegian offshore basins have accumulated over many years and will serve as a basis for the present study; and there is also a large data base on formation water chemistry from the same basins. Geochemical calculations will be carried out with the PHREEQC software (Parkhurst & Appelo, 2013).

• Requirements:
• Basic knowledge of chemistry
• Basic programming skills