Ghawar Field
Encyclopedia
Ghawar is an oil field
in Saudi Arabia
. It is located in Al-Ahssa, Saudi Arabia. Measuring 280 by, it is by far the largest conventional oil field in the world. The field is entirely owned and operated by Saudi Aramco
, the nationalized Saudi oil company. Relatively little is known about Ghawar because the company and Saudi government closely guard field performance information and per-field production details. Available information is predominantly historical (pre-nationalization), from incidental technical publications, or anecdotal.
above a basement fault block dating to Carboniferous
time, about 320 million years ago; Cretaceous
tectonic activity, as the northeast margin of Africa began to impinge on southwest Asia, enhanced the structure. Reservoir rocks are Jurassic
Arab-D limestones with exceptional porosity (as much as 35% of the rock in places), sourced
from the Jurassic Hanifa formation, a marine shelf deposit of mud and lime with as much as 5% organic material (1% to 7% is considered good oil source rock). The seal is an evaporitic
package of rocks including impermeable anhydrite
.
and the city of Al-Hofuf are located on Ghawar's east flank, corresponding to the 'Uthmaniyah production area. Ghawar was discovered in 1948 and put on stream in 1951. Some sources claim Ghawar peaked
in 2005, though this is strongly contested by the field operators.
Saudi Aramco reports that Ghawar has produced 48% of its proven reserves
produced between 1948 and 2000 came from Ghawar. Cumulative production until April 2010 has exceeded 65 Goilbbl. Currently, Ghawar is estimated to produce over 5 Moilbbl of oil a day (6.25% of global production).
Ghawar also produces approximately 2 Gcuft of natural gas
per day.
Matthew Simmons
, in his book Twilight in the Desert, suggests that production from the Ghawar field and Saudi Arabia may soon peak
.
When appraised in the 1970s, the field was assessed to have 170 Goilbbl of original oil in place, with about 60 Goilbbl recoverable (1975 Aramco estimate quoted by Matt Simmons). The second figure, at least, was understated, since that production figure has already been exceeded.
Oil field
An oil field is a region with an abundance of oil wells extracting petroleum from below ground. Because the oil reservoirs typically extend over a large area, possibly several hundred kilometres across, full exploitation entails multiple wells scattered across the area...
in Saudi Arabia
Saudi Arabia
The Kingdom of Saudi Arabia , commonly known in British English as Saudi Arabia and in Arabic as as-Sa‘ūdiyyah , is the largest state in Western Asia by land area, constituting the bulk of the Arabian Peninsula, and the second-largest in the Arab World...
. It is located in Al-Ahssa, Saudi Arabia. Measuring 280 by, it is by far the largest conventional oil field in the world. The field is entirely owned and operated by Saudi Aramco
Saudi Aramco
Saudi Aramco , officially the Saudi Arabian Oil Company, is the national oil company of Saudi Arabia.Saudi Aramco is the world's largest and most valuable privately-held company, with estimates of its value in 2011 to be $7 trillion USD.Saudi Aramco has both the largest proven crude oil reserves,...
, the nationalized Saudi oil company. Relatively little is known about Ghawar because the company and Saudi government closely guard field performance information and per-field production details. Available information is predominantly historical (pre-nationalization), from incidental technical publications, or anecdotal.
Geology
Ghawar occupies an anticlineAnticline
In structural geology, an anticline is a fold that is convex up and has its oldest beds at its core. The term is not to be confused with antiform, which is a purely descriptive term for any fold that is convex up. Therefore if age relationships In structural geology, an anticline is a fold that is...
above a basement fault block dating to Carboniferous
Carboniferous
The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...
time, about 320 million years ago; Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
tectonic activity, as the northeast margin of Africa began to impinge on southwest Asia, enhanced the structure. Reservoir rocks are Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
Arab-D limestones with exceptional porosity (as much as 35% of the rock in places), sourced
Source rock
In petroleum geology, source rock refers to rocks from which hydrocarbons have been generated or are capable of being generated. They form one of the necessary elements of a working petroleum system. They are organic-rich sediments that may have been deposited in a variety of environments including...
from the Jurassic Hanifa formation, a marine shelf deposit of mud and lime with as much as 5% organic material (1% to 7% is considered good oil source rock). The seal is an evaporitic
Evaporite
Evaporite is a name for a water-soluble mineral sediment that result from concentration and crystallization by evaporation from an aqueous solution. There are two types of evaporate deposits, marine which can also be described as ocean deposits, and non-marine which are found in standing bodies of...
package of rocks including impermeable anhydrite
Anhydrite
Anhydrite is a mineral – anhydrous calcium sulfate, CaSO4. It is in the orthorhombic crystal system, with three directions of perfect cleavage parallel to the three planes of symmetry. It is not isomorphous with the orthorhombic barium and strontium sulfates, as might be expected from the...
.
History
Historically, Ghawar has been subdivided into five production areas, from north to south: 'Ain Dar and Shedgum, 'Uthmaniyah, Hawiyah and Haradh. The major oasis of Al-AhsaAl-Hasa
Al-Ahsa is the largest governorate in Saudi Arabia's Eastern Province, named after Al-Ahsa oasis. The name Al-Ahsa is also given to the biggest city in the region, Hofuf. In classic Arabic, Ahsa means the sound of water underground. It has one of the largest oases in the world with Date Palms of...
and the city of Al-Hofuf are located on Ghawar's east flank, corresponding to the 'Uthmaniyah production area. Ghawar was discovered in 1948 and put on stream in 1951. Some sources claim Ghawar peaked
Peak oil
Peak oil is the point in time when the maximum rate of global petroleum extraction is reached, after which the rate of production enters terminal decline. This concept is based on the observed production rates of individual oil wells, projected reserves and the combined production rate of a field...
in 2005, though this is strongly contested by the field operators.
Saudi Aramco reports that Ghawar has produced 48% of its proven reserves
Production
Approximately 60-65% of all Saudi oilPetroleum
Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...
produced between 1948 and 2000 came from Ghawar. Cumulative production until April 2010 has exceeded 65 Goilbbl. Currently, Ghawar is estimated to produce over 5 Moilbbl of oil a day (6.25% of global production).
Ghawar also produces approximately 2 Gcuft of natural gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
per day.
Reserves
In April 2010, Saad al-Treiki, Vice-President for Operations at Aramco, stated in a news conference reported in Saudi media that over 65 Goilbbl have been produced from the field since 1951. Treiki further stated that the total reserves of the field had originally exceeded 100 GoilbblMatthew Simmons
Matthew Simmons
Matthew Roy Simmons was founder and chairman emeritus of Simmons & Company International, and was a prominent advocate of peak oil. Simmons was motivated by the 1973 energy crisis to create an investment banking firm catering to oil companies. In his previous capacity, he served as energy...
, in his book Twilight in the Desert, suggests that production from the Ghawar field and Saudi Arabia may soon peak
Hubbert peak theory
The Hubbert peak theory posits that for any given geographical area, from an individual oil-producing region to the planet as a whole, the rate of petroleum production tends to follow a bell-shaped curve...
.
When appraised in the 1970s, the field was assessed to have 170 Goilbbl of original oil in place, with about 60 Goilbbl recoverable (1975 Aramco estimate quoted by Matt Simmons). The second figure, at least, was understated, since that production figure has already been exceeded.
External links
- A theoretical look at the future of the field
- Articles on Ghawar and analysis on its reserves from The Oil DrumThe Oil DrumThe Oil Drum is a web-based, interactive energy, peak oil and sustainability think tank and community devoted to the discussion of energy issues and their impact on society. The Oil Drum is facilitated by the Institute for the Study of Energy and Our Future, a Colorado non-profit corporation...
- Terrorists and Ghawar
- Saudi Aramco website (source of most data in this article).