Contrat de Collaboration Gdf-Suez/Université Paris-Sud. Sedimentological control of diagenetic processes of the tidal sandstones of the Upper Cape Hay formation: Impact on reservoir properties. 2013 – Responsable scientifique: Benjamin Brigaud
Clastics reservoir of the Cape Hay formation (Permian age), from the Petrel gas field, J.Bonaparte basin, Australia, overcame a high diagenetic overprint resulting in very variable reservoir properties, with porosity (Phi) ranging from a few percents to up to 25%, and permeability (k) varying between 0.01 mD to several hundreds of mD.
Objectives of the study:
The objectives of the study consist to better understand the main diagenetic processes and identifying their possible control factors. Especially it aims at answering questions such as:
- Are diagentic processes related to depositional environment?
- What is the role of initial mineralogy on diagenetic evolution?
- What is the nature of fluids at the origin of silica and carbonate cements?
- Is carbonate cement related to the vicinity of shell fragments layers?
- What are the types of fluids circulating in the reservoir and their role on dissolution and/or cementation?
- Are they related to early or late diagenesis?
- What is the impact of mixing of water (marine versus fresh continental water and intermediate salinity water) on the nature, flocculation and expression of clays in the sediment?
- What is the depositional environment favouring fluid circulations and flocculation of clay minerals around grains?
- Could we quantify the porosity loss (increase) due to clay type & expression?
- What is the diagenetic sequence?
Saïag, J., Brigaud, B., Portier, E., Desaubliaux, G., Bucherie, A., Miska, S., Pagel, M., 2016. Sedimentological control on the diagenesis and reservoir quality of tidal sandstones of the Upper Cape Hay Formation (Permian, Bonaparte Basin, Australia). Marine and Petroleum Geology. 77, 597-624