STRATIGRAPHY, DEPOSITIONAL SETTING AND RESERVOIR CHARACTERISTICS OF TURONIAN ‐ CAMPANIAN CARBONATES IN CENTRAL IRAQ
Middle Turonian ‐ lower Companion carbonates in central Iraq contain estimated cumulative reserves of around 9 billion brl. More than 90% of this oil is in the Turonian Khasib Formation which forms an important reservoir at the giant East Baghdad and Balad oilfields and also at a number of other fie...
| Published in: | Journal of Petroleum Geology |
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| Main Author: | |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Wiley
2004
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| Online Access: | http://dx.doi.org/10.1111/j.1747-5457.2004.tb00063.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1747-5457.2004.tb00063.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1747-5457.2004.tb00063.x |
| Summary: | Middle Turonian ‐ lower Companion carbonates in central Iraq contain estimated cumulative reserves of around 9 billion brl. More than 90% of this oil is in the Turonian Khasib Formation which forms an important reservoir at the giant East Baghdad and Balad oilfields and also at a number of other fields in central and southern Iraq. Minor volumes of oil are present in the overlying Tanuma and Sa'di Formations. The Khasib Formation consists of limestones and marlstones containing planktonic foraminifera and calcispheres together with extensively bioturbated chalks. These sediments were laid down in a basimal to sub‐basinal setting which evolved into a shallow‐ marine shelf or coastal lagoon. The best porosity (around 20%) occurs in the intensively bioturbated middle part of the formation, in which chalky matrix porosity is enhanced by an extensive network of micro‐fractures. The Tithonian‐Berriasian Chia Gara and the Valanginian‐Campanian Balambo Formations are potential source rocks for this oil. Organic matter is mostly marine Type II kerogen or mixed marine‐continental. |
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