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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 68 (1984)

Issue: 9. (September)

First Page: 1199

Last Page: 1199

Title: Paleozoic Oil and Gas Potential of Arabian Basin: ABSTRACT

Author(s): Abdulaziz Abdullah Al-Laboun

Abstract:

The central and northwestern region of the greater Arabian basin contains more than 5,000 m (16,400 ft) of oil- and gas-prospective clastic and carbonate Paleozoic sediments. The Hail-Rutbah arch divides the region into two Paleozoic basins, the western Tabuk basin on the west and the Widyan basin on the east. The Tabuk basin is filled with Cambrian to Devonian sediments, whereas the Widyan basin contains sediments ranging in age from Cambrian through Late Permian. A north-south-trending Precambrian platform separates these basins from the eastern sector of the greater Arabian basin.

The Cambrian-Ordovician Saq Sandstone, composed of fluvial and marginal-marine sandstones and minor shales, overlies Precambrian basement.

The Ordovician-Silurian Tabuk Formation consists of cyclically deposited marine and marginally marine clastic sediments. Three shale members, the Hanadir, Ra'an, and Quasaiba, are separated by siltstones and sandstones that pinch out basinward where shale becomes dominant. These shale members are covered by regressive sandstones of the Sharawra Member. Uplift and erosion followed deposition of the Sharawra.

Unconformably overlying the Tabuk Formation is the coarse and pebbly continental sandstone of the Tawil Member of the Devonian Jauf Formation. Alternating marine and nonmarine conditions followed deposition of the Tawil Member, producing interbedded carbonates and clastics. A major regional uplift accompanied by erosion followed deposition of the Jauf Formation. The uplift affected the entire central and northwestern basin region and it is believed the Hail-Rutbah arch came into being at this time, creating the two basins.

No post-Devonian Paleozoic deposition is recorded in the rocks of the western Tabuk basin; however, thick Carboniferous-Upper Permian sediments occur in the Widyan basin. The Carboniferous to middle Permian Berwath Formation was deposited in the center of the Widyan basin and was covered by the Unayzah Formation, which transgressed the area and overlapped older rocks and paleohighs. The middle to Upper Permian is represented by carbonates of the Khuff Formation, laid down by the transgressive sea.

Precambrian structural features significantly influenced structural trends and sedimentary deposition during the Paleozoic. Major stratigraphic breaks or unconformities are believed associated with the Caledonian and Hercynian orogenies.

The most significant factor relating to the oil and gas prospectiveness of the Tabuk and Widyan basins is the presence of thick alternating source and reservoir sections. The facies vary laterally, with sandstone grading to shale basinward. The facies changes combined with several unconformities and structural folding and faulting enhance the hydrocarbon potential of the two basins. Also, known shows and recoveries of oil and gas from the Paleozoic section in the eastern Arabian basin further support the possibility of the presence of commercial quantities of hydrocarbons in these basins.

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