Tag: diagenesis

Sedimentological control on the diagenesis and reservoir quality of tidal sandstones of the Upper Cape Hay Formation (Permian, Bonaparte Basin, Australia)

The deep siliciclastic reservoir (>3500 m) of the Upper Cape Hay Formation of the Bonaparte Basin (Petrel gas field, Petrel sub-basin, Permian) exhibits wide heterogeneity in porosity (2–26%) and permeability (0.001–2500 mD). To investigate this variability, 42 samples were taken from five wells drilled through this formation. Six facies were identified from core descriptions and microscopic study of the sandstones. These facies are typical of a tide-dominated estuary, and include (1) mud flat, (2) sand flat, (3) top of tidal sand bar, (4) middle of tidal sand bar, (5) bottom of tidal sand bar, and (6) outer estuary facies. The paragenetic sequence comprises the emplacement of early aggregates of ferrous clay mineral precursors, mechanical compaction, recrystallization of those ferrous clay mineral precursors to Fe-rich chlorite and crystallization of Fe-rich chlorite forming coatings around detrital grains, chemical compaction, development of quartz overgrowth, feldspar alteration, crystallization of dickite and illite-rich illite/smectite (I-S) mixed layers, and ferrous calcite cementation. The middle and top of the tidal bars generally exhibit the highest porosity (Φ > 10%) and permeability values (k > 1 mD). Feldspar alteration released silica and aluminium into the reservoir promoting the development of dickite and illite-rich I/S mixed layers, which tended to destroy porosity and permeability, as calcite cements and quartz overgrowths. Diagenetic chlorite coatings around detrital grains are restricted to the sand bar facies deposited at the end of the last third-order transgressive systems tract of the Cape Hay Formation. The formation and conservation of ferrous clay precursors seems to be possible in an estuarine environment where seawater and fresh water are mixed and tidal sand bars are formed. These ferrous clay precursors recrystallized to Fe-rich chlorite coating after mechanical compaction. These coatings inhibited quartz cementation and prove to be the key parameter behind good reservoir qualities.

Link

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

Permanent link to this article: http://hebergement.u-psud.fr/reliefetbassin/index.php/archive/sedimentological-control-on-the-diagenesis-and-reservoir-quality-of-tidal-sandstones-of-the-upper-cape-hay-formation-permian-bonaparte-basin-australia/

AGBP congress

Find summaries of team’s work presented at the AGBP congress (november 2014) in Paris. PDF

 

Permanent link to this article: http://hebergement.u-psud.fr/reliefetbassin/index.php/archive/agbp-congress/

Feedback to the thematic meeting of the French Association of Sedimentologists

The 4th July2014, the thematic meeting of the French Association of Sedimentologists organized by the Geosciences Paris Sud (GEOPS) Laboratory and entitled “Diagenesis: recent advances and perspectives” was attended by 110 people in Orsay. This meeting was organized in honor to Maurice Pagel (Emeritus Professor at the University Paris-Sud), which focused much of his career to understand the diagenetic processes “ie physical, chemical or biological transformations occurring in sediments, immediately after the deposit until today “in sedimentary basins.

The aim was to bring together specialists covering an area ranging from academic approaches to industrial applications to provide an update on our understanding of diagenetic processes in carbonate, clastic rocks and their integration in the prediction of reservoir qualities, or oil / metal accumulation..

The main interest was to bring together researchers from academia and from major oil company  engineers from either public agency such as BRGM (French Geological Survey), Andra, IFPEN or major oil and gas company as total and GDF-Suez. The twenty presentations, including two conducted by invited researchers from the University of Liverpool and the University of Leuven, allowed to make a status report on new advances in the field including thermal history reconstruction methods or dating methods or reservoir modeling linking reservoirs quality and diagenetic processes. The meeting have been an opportunity to discuss the new advances in diagenesis  and identify future challenges in the field of diagenesis in order to bring out european collaborations.

comm_diagenese

Permanent link to this article: http://hebergement.u-psud.fr/reliefetbassin/index.php/archive/feedback-to-the-thematic-meeting-of-the-french-association-of-sedimentologists/