Abstract
The Arab Formation distributed in the West Mubarras Concession, offshore Abu Dhabi, U.A.E., consists of limestone, dolomite and anhydrite. The way of lithological succession in the Arab Formation is well explained by shallowing upward sabkha deposional model. Reservoir rocks can be classified into five types as a result of complex combination of sedimentary facies originated from different environments and diagenesis at various timing of burial history. They are “Limegrainstone”, RD1-1, RD1-2, HD1-1 and HD1-2 respectively.“Limegrainstone” has intergranular porosity which causes high permeability. Bloky calcite cement reduced porosity at downflank of the structure.RD1-1 and RD1-2 are dolomites originated from grainstone or packstone. RD1-1 preserves original intergranular porosity which causes highest permeability among all dolomite reservoir rocks. Porosity in RD1-2 is mainly moldic which was derived from leaching of grains. Because of poor continuity between molds, permeability of RD1-2 is considerably lower than that of RD1-1.HD1-1 is a coarse grained “sucrosic dolomite” with intercrystalline pores. Large pores sometimes causes high permeability. Porosity decreases toward downflank of the structures because of crystal interlocking enhanced by reaction with formation water.HD1-2 is a very fine crystalline dolomite originated from limemudstone or wackestone. Due to very small size intercrystalline pores, even in fairly porous rocks permeability is very low.
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call