Open AccessCenomanian-Early Campanian Carbonate Reservoir Rocks of Northwestern Iraq: Diagenesis and Porosity Development
Author(s) -
Mohamed Al-Haj,
Ali I. AlJuboury,
Aboosh H. Al-Hadidy,
Dalia Kamran Hassan
Publication year - 2022
Publication title -
mağallaẗ al-kitāb li-l-ʿulūm al-ṣirfaẗ
Language(s) - English
Resource type - Journals
eISSN - 2617-8141
pISSN - 2617-1260
DOI - 10.32441/kjps.02.02.p1
Subject(s) - geology , diagenesis , dolomitization , cenomanian , carbonate , cretaceous , geochemistry , unconformity , carbonate rock , cementation (geology) , paleontology , facies , sedimentary rock , archaeology , materials science , structural basin , cement , metallurgy , history
The present work focuses on the upper Cretaceous (Cenomanian-early Campanian)carbonate successions in selected wells from northwestern Iraq. These successions arerepresented by Gir Bir (Cenomanian-early Turonian), Wajna (late Santonian) and Mushorah (early Campanian) Formations. The succession has affected by early burial near-surface, unconformity-related and deep burial diagenesis represented by cementation, neomorphism, dolomitization, dedolomitization, silicification, authigenesis of glauconite and pyrite, compaction, micritization, solution and porosity formation. The common porosity types are intergranular, fenestral, intercrystalline, moldic, vuggy, channel and fracture. Three porosity zones (I, II, and III) are identified depending on variation in gamma ray which reflects their shale content. The upper part of zone (II) is highly porous and regarded on the main reservoir unit in the middle and upper parts of the Gir Bir Formation. Fracture and moldic and vuggy dissolution features in addition to karstic and fissure features are responsible for the porosity increase in the fractured reservoir unit.