Impact of structural setting on diagenesis of fluvial and tidal sandstones: The Bahi Formation, Upper Cretaceous, NW Sirt Basin, North Central Libya
2012 (English)In: Marine and Petroleum Geology, ISSN 0264-8172, E-ISSN 1873-4073, Vol. 38, no 1, 211-231 p.Article in journal (Refereed) Published
This petrographic, mineral chemical, fluid inclusion, and stable isotopic study shows that the distribution of diagenetic modifications and their influence on reservoir quality and heterogeneity in tidal and fluvial sandstones of the Upper Cretaceous Bahi Sandstones in the rift Sirt Basin, NW Libya varies systematically along a series of closely-spaced, dominantly normal faults between the basin margin and more basinward-located areas. Shallow eogenetic modifications resulting from the percolation of meteoric waters, include infiltration of grain coating clays, kaolinitization of detrital silicates, and cementation by dolomite and K-feldspar overgrowths. Mesogenetic alterations (>70 °C, >2 km) include feldspar albitization, illitization of infiltrated clay and kaolinite, conversion of kaolinite into dickite, and cementation by quartz overgrowths (T h 112 °C-134 °C), barite (T h 145 °C-158 °C) and Fe-carbonates. The restriction of barite and Fe-carbonate cements to the basinward-located sandstones suggests formation by hydrothermal fluids along the faults. Extensive feldspar dissolution and formation of moldic pores in sandstones from the basin margin were probably caused by deep percolation of meteoric waters. Results from this study regarding the structural control on the spatial distribution of diagenetic alterations have implications for constraining the flux of pore fluids and, by extension, reservoir quality in analogous epicratonic rift basins.
Place, publisher, year, edition, pages
2012. Vol. 38, no 1, 211-231 p.
Diagenesis, Hydrothermal fluids, Libya, Reservoir quality, Sandstone, Sirt Basin, Structural setting, Barite, Cementing (shafts), Cements, Chemical modification, Feldspar, Kaolinite, Mineralogy, Quartz, Sedimentology, Silicates, Solvents, Structural dynamics, Cretaceous, hydrocarbon reservoir, hydrothermal fluid, structural control, Libyan Arab Jamahiriya, Sirte Basin
Earth and Related Environmental Sciences
Research subject Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
IdentifiersURN: urn:nbn:se:uu:diva-184894DOI: 10.1016/j.marpetgeo.2011.05.006ISI: 000310668100016OAI: oai:DiVA.org:uu-184894DiVA: diva2:570913