Where is the ghawar oil field found

The oil-water contact at Ghawar dips to the northeast, dipping more than feet m between the southwest end of Haradh and the Fazran area.

The contact is consistently higher on the west flank of the field than on the east, and a tar mat is associated with the original contact. Water injection wells are completed above this tar mat for pressure maintenance. This peripheral waterflood project began in the early sixties in the northern parts of the field. By the time that the southern Hawiyah and Haradh areas were developed during to , horizontal-drilling technology was available. Horizontal injectors were completed above the tar mat to provide line source distribution of water along the periphery of the field.

Other reservoirs include clastics of the Pre-Qusaiba section that are fault bounded and sourced laterally by the down-faulted Qusaiba Shale Member. Many of these Pre-Qusaiba clastics have had some hydrocarbon shows but are poor-quality reservoirs owing to silica cementation. The Upper Permian Unayzah Formation is a complex succession of generally red continental clastics consisting of braided-plain, channel-fill, and eolian sand and flood-plain silt that were deposited on the pre-Unayzah Hercynian unconformity Senalp and Al-Duaiji, ; Evans and others, ; Konert and others, Regional surface and subsurface data indicate that the Unayzah is widespread over much of the eastern Arabian Plate Al-Laboun, A recent study by Heine in press showed that sandstones of the Unayzah in the southern Ghawar area are cold-climate periglacial dunes deposited on an eroded surface that trends across central Saudi Arabia, and possibly over Bahrain and Qatar.

Deposition of continental clastics of the Unayzah re p resents a major change in sedimentation that preceded a major marine transgression and widespread deposition of carbonates and evaporites of the Khuff Formation.

The Unayzah Formation is composed of cycles of crossbedded, fine-to coarse-grained sandstones, siltstones, and claystones with thin beds of argillaceous limestone. In central Saudi Arabia, the lowermost part of the Unayzah consists of debris-flow gravels and coarse clastics, which infill the Hercynian erosional unconformity on the underlying Qusaiba Shale Senalp and Al-Duaiji, The Unayzah Formation fines upward into more distal, braided-stream bars and channel-fill sandstones, and flood-plain siltstones.

The cyclic nature of the Unayzah suggests a fluctuating sea level. The upper Unayzah unit A is the principal reservoir, averaging about 20 percent porosity. Permeability of several darcies is not uncommon; however, both porosity and permeability vary due to kaolinite and illite cements McGillivray and Husseini, In the Greater Ghawar area, the principal Pre-Khuff hydrocarbon reservoir in the southern area Haradh substructure field at Ghawar, and adjacent Sahba, Waqr, and Tinat fields is the Unayzah Formation, whereas the Lower to Middle Devonian Jauf Formation is the main producing reservoir in the northern Ghawar area Ghawar substructure fields: Hawiyah, Uthmaniyah, and Shedgum.

In the south Ghawar area, the Unayzah is generally divided into two sandstone reservoir units separated by a siltstone member Wender and others, Gas is produced from most Paleozoic reservoirs at Ghawar; however, Qusaiba-sourced premium crude is produced from the Unayzah at the Tinat field structure immediately to the southeast. The Unayzah is missing in the north half of Ghawar field McGillivray, but is present in the south half of Ghawar, where it thickens from 0 to greater than m at Tinat field.

Porosity of the upper Unayzah-A pay zone ranges from 5 to 25 percent and averages about 12 percent Wender and others, The field measures approximately km-long and up to 36km-wide. The main reservoirs of the Ghawar field include the Arab-D reservoir of the Jurassic-age mudstone formations, the Lower Fadhili carbonate reservoir of the Dhruma Formation, and the Khuff A,B,C, and D reservoirs of the Khuff non-associated gas formation.

The Ghawar field was estimated to contain Further, the southern part of the Greater Ghawar area is believed to host significant volume of unconventional gas and associated liquid resources lying trapped in rocks. Saudi Aramco has started trial production in the area to evaluate the prospects of unconventional production, as part of its unconventional resources programme, which is primarily focused on South Ghawar as well as Jafurah and North Arabia areas.

Ghawar field discovery and development details The first oil discovery at Ghawar took place in with the successful drilling of Ain Dar No. The well continued to produce dry oil without any water contamination until Haradh was the second oil discovery in the Ghawar field.

Although the drilling of Haradh No. The Uthmaniyah and Shedgum subfield areas were discovered in and , but were brought on stream in and , respectively.

Production at Ghawar was estimated at 5 million barrels per day, but that estimate was lowered to 3. Image Credit: Energy in Depth. Are there other large oil fields?

There are absolutely other large oil fields around the world. Here are some of the honorable mentions:. The Greater Burgan oilfield in Kuwait is the third largest oilfield in the world, with over 40 billion barrels of oil recoverable. The surface area is approximately 1, square kilometers and started producing oil in The field currently produces between 1.

Image Credit: Wikimedia Commons. You must log in to edit PetroWiki. Help with editing. Content of PetroWiki is intended for personal use only and to supplement, not replace, engineering judgment. SPE disclaims any and all liability for your use of such content. More information. It measures by 30 km by 19 mi , it is by far the largest conventional oil field in the world.

The Ghawar field accounts for more than half of the cumulative oil production of Saudi Arabia.