2019 AAPG Annual Convention and Exhibition:

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Geology of West Karun Oil Fields Shared Between Iran and Iraq


Geology of West Karun Oil Fields Shared Between Iran & Iraq Yosef Shahin General Manager, Medgeo Amman 11814, Jordan Mobile: +962 77 550 0 724 EM: [email protected] ABSTARCT Iran-Iraq boundary has (23) oil fields on both sides of the border. These fields contain more than (30) billion barrels of oil reserves with production capacity of more than (5) million barrels of oil per day. The presentation illustrates the geology and reservoir extensions of oil fields located in Khuzestan Province, SW Iran, west of Karun River and crossing over into southern Iraqi Provinces of Basrah & Misan. The shared supergiant complex of Azedgan- Yadavaran-Majnoon contains more than (20) billion barrels of oil reserves. These joint fields are considered green and none of these fields have been developed to full capacity. Late Oligocene-Early Miocene Asmari Formation is an important reservoirs in in these fields and it is part of the Asmari-Gasharan-Khadzumi Petroleum System which provides massive oil reserves- production in Iran, Iraq and other Gulf countries. Asmari Formation consists of about (400) m of cyclic platform limestone, dolostone, sandstone, and shale. The Formation is equivalent to Euphrates, Ibrahim, Tarjil and Palani Formations in Iraq and to Dammam, Burgan Formations in Saudi Arabia and Kuwait. Reservoirs of Bangestan Group include the thick Sarvak limestone Reservoir (300m to 1000m thick) of Cenomanian- Turonian age and the Illam Reservoir (50m to 200m thick) of Turonian-Campanian age. These two reservoirs form a single reservoir in most of the Dezful Embayment in SW Iran and are capped by Gurpi/Pabdeh marls. Sarvak formation is the lateral age-equivalent of the Mauddud, Rumaila & Mishrif Reservoirs in Iraq. Ilam Formation consists of fine-grained argillaceous limestones with interbedded shales, deposited under shallow to deep open-marine conditions. Diagenetic processes have reduced its reservoir quality, while extensive fracturing enhances reservoir properties. The Albian Kazhdumi Formation consists of (300-500) m dark bituminous shale, is the main source horizon in SW Iran. Kazhdumi TOC average is (6) %, classifying Kazhdumi as one of the richest source rocks in Iran. The Lower Cretaceous Fahliyan Formation makes major reservoir West of Karun River into border with Iraq. This formation is equivalent to the lower Ratawi - Minagish Formation, which is a significant hydrocarbon reservoir in Iraq, Kuwait and Saudi Arabia. Fahliyan is part of Khami Group, which attains thickness of more than (1500) meter in the subsurface of Dezful Embayment, consists of limestone deposited in a shallow carbonate shelf environment. Fahliyan is sealed by Gadvan compact clastics and sourced from Garau - Jurassic Formations.