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Weekly UpdatesDiscovered in 1948 by the then US-owned Aramco (Chevron, Texaco, Exxon & Mobil), Ghawar is the largest axis of fields in the world and is the main producer of Arab Light crude oil in Saudi Arabia. It is 250 km long and 15 km wide. It contains several fields, of which eight are major oil producers, and huge fields of natural gas in a Khuff reservoir deep beneath the oil formations (Fms). Ghawar's recoverable crude oil reserves exceed 70 bn barrels. Oil in place in the Ghawar region is estimated to be over 300 bn barrels.
Exxon found the first Ghawar field at Ain Dar in 1948, having joined Aramco in 1947. That find led to discovery and development of other fields by Exxon. (This was partly why ExxonMobil in 2001 chose to lead one of three core ventures to develop a huge south Ghawar gas field in partnership with other majors. ExxonMobil led another core project. But talks on both JVs collapsed later and the US super-major abandoned the Saudi Gas Initiative - see Vol. 61, Gas Market Trends No. 13).
The bulk of Ghawar's produced oil reserves occur in limestones of the Jurassic Arab A, B, C and D units, mostly at a depth of 6,920 feet, with big amounts in older Jurassic limestone. Beneath them lie giant Khuff and pre-Khuff gas Fms.
The main producing Ghawar fields are, from north to south: Ain Dar, Shedgum, Uthmaniyah, Farzan, Ghawar, al-Udayliyah, Hawiyah and Haradh. Their capacity is 5.3m b/d, of which most of the heavier oil production streams have been mothballed. It was said in 1990, when total Saudi capacity was less than 8m b/d, that these fields still had the potential to produce 4m b/d, as some of the wells were filled with diesel to keep them ready. In 1980, as Saudi output totalled 9.9m b/d, the Ghawar fields at times produced over 6.5m b/d. But the reserver was damaged as a result, and some of the older fields like Ain Dar have begun to decline.
Ain Dar and Shedgum fields have had an EOR system based on seawater injection. In September 2003 Snamprogetti of Italy was selected for a $110m EPC job. The FEED was done by Bechtel. The PMC is SNC Lavalin of Canada.
The main boost to Arab Light (AL) capacity came from a 520,000 b/d expansion at Hawiyah. Deep beneath Hawiyah's oil reservoir lies the Jawf field of non-associated Khuff gas. A $2 bn, 1,440 MCF/d gas processing plant built at Hawiyah came on stream in late 2001 as the 4th such facility in the Master Gas System (MGS). Hawiyah plant produces 170,000 b/d of condensate and 1,000 t/d of sulphur. The plant is being expanded by 800 MCF/d.
The Jawf gas/condensate field was found on July 21, 1994, as the Hawiyah-200 exploratory well yielded 20.2 MCF/d of sweet gas and 3,286 b/d of condensates from an interval of 13,650-14,353 feet. The well was spudded in January 1994 and was the first in a series of deep tests to explore new gas reserves on the flanks of Ghawar. It encountered zones bearing extensive sour and sweet gas deposits in a Khuff Fm at 12,500 ft. Now Jawf produces non-associated gas from six wells.
Deeper drilling through the Jurassic beneath other Ghawar oil structures had since the 1980s proved up large reserves of gas sometimes with condensate in Permian Khuff limestones and pre-Khuff sandstones. The deposits had been actively sought as industries and utilities in the kingdom, which depended on associated gas for power or feedstock, had been deprived of ethane and methane because oil production was cut back. Now Saudi Aramco is developing Khuff and pre-Khuff gas beneath Ghawar.
Haradh produces 900,000 b/d of AL. It has three 300,000 b/d GOSPs, with some of the heavy oil produced in the Ghawar area shut in. In March 2001, Snamprogetti got a $140m job to upgrade Haradh-I and build the second 300,000 b/d GOSP for Haradh-II. Haradh-III in February 2006 reached its 300,000 b/d capacity ahead of schedule. The field's performance exceeded virtually all pre-project goals. Haradth-III also produces 160 MCF/d of gas. The huge Khuff gas reservoir deep beneath Haradh's oil Fms has been partly developed.
Maximum Reservoir Contact (MRC) wells, smart completions, geo-steering, and the latest ITs were part of Haradh-III, at a scale and complexity unprecedented in the E&P industry. A decade from now, these will become standard in the lexicon of mega-projects. Initial production from Haradh-I occurred in May 1996, followed by Haradh II in April 2003
Saudi Aramco has had a $2 bn, 1,620 MCF/d gas processing plant built at Haradh, the 5th such facility in the MGS, which went into full production in late 2003. It is the second to process non-associated gas, and also processes associated gas from the Shaybah field. The plant produces 145,000 b/d of condensate. The plant is being expanded by 500 MCF/d.
The kingdom's 6th such facility, Straddle Plant, treats 3,800 MCF/d of gas and extracts about 150,000-200,000 b/d of NGLs from the Hawiyah and Haradh gas plants. The remaining gas will be produced from three areas in the remote Rub' al-Khali (RaK) region offered for gas E&P to foreign companies (see gmt13SaudiGeoSep24-07).
In parallel, Saudi Aramco has had the East/West (E/W) pipeline converted to carry gas as well as crude oil. This followed the 2001 conversion by Saipem of the AY-1 pipeline pumping 300 MCF/d to the west.
When all the gas plants and their expansions, including an ethane recovery unit at the Berri gas facility, become operational, Saudi Arabia's outputs by 2008 would have reached almost 10,000 MCF/d of gas, 900 MCF/d of ethane and 950,000 b/d of NGL. By 2010 gas production would reach 20,000 MCF/d.
Uthmaniyah is another Ghawar oilfield. There, a major gas processing plant with a capacity of 1,600 BCF/d has been expanded to 2,400 MCF/d. A 152 km underground gas pipeline, known as UBTG-3, has been built linking the gas facility to the processing plants of Ju'aymah and Berri. Two new GOSPs at Uthmaniyah were built in late 1992.
The Ghawar fields are now producing close to capacity, with the output being AL crude oil. The other Ghawar fields producing this grade are Khurais, Harmaliya and Abu Hadriya.
Khurais, expanded under Saudi Aramco's first programme which raised its capacity from 75,000 b/d to 150,000 b/d, is being expanded on a full scale. It will have six new GOSPs with a total capacity of 1.2m b/d by 2009, to be added to the existing 150,000 b/d. But the 1.2m b/d addition will be AL. The PMC for the fast-track expansion is Foster Wheeler.
New installations are to include facilities to inject 2m b/d of seawater into Khurais, Abu Jifan and Mazalij fields to support increased oil production. Companies were due to submit prequalifications by an extended deadline of Oct. 8 for the main construction packages. The largest - Package-1 worth about $2 bn - will cover construction of central processing facilities (CPFs) and include a GOSP, wet crude handling vessels, gas stabilisation columns, compression and liquid separation facilities, in-field trunklines and related works. It will also entail an upgrade of support facilities at the Ju'aymah gas plant through installation of steam boilers, water pumps and plant and piping facilities. The facilities will be built to handle 115 MCF/d of gas and 120,000 b/d of NGLs to be produced from the new CPF. Package 2, worth $1 bn, will cover installation of seawater supply and injection facilities at Khurais and the expansion of the Qurrayah water treatment plant, aimed at supplying 2,000 b/d of treated water. Package-3, worth $500m, will include supply and installation of pipelines for seawater intake. Package-4 will be for supply and installation 80 km of 24-28-inch pipelines at Khurais to transport crude oil, gas and NGL and the Phase-2 expansion of the E/W NGL pipeline by installation of new pumping stations and three 14-32-inch, 340-km pipelines. Package-5, worth $1 bn, will include construction of co-generation, infrastructure, and product handling and storage facilities - to cover accommodation and related major civil works.
Found in 1957 and on stream in 1970, Khurais is about 70 km long trending north and north-west. It is about 100 km west of Ghawar. The field has three Upper/Mid-Jurassic oil zones producing 33[degrees] API oil from Arab D and Hanifa carbonates, and 36[degrees] oil from the deeper Fadhili reservoir. Oil in place at Khurais exceeds 20 bn barrels. But only 7 bn barrels would be recoverable at current cost rates. The field's full potential can be proven after extensive work on other related structures. It was partly in view of such considerations that Khurais was shut down as oil prices began to fall in 1985. Total Saudi Aramco output then declined to less than 3m b/d.
Hawiyah's gas processing capacity is being raised 800 MCF/d to 2,400 MCF/d by 2008. Jacobs Engineering is the PMC on the Hawiyah NGL recovery programme.
Qatif, a giant field shut down in 1995, has been reactivated and expanded under a $2 bn incremental oil and associated gas project which raised its capacity from 200,000 b/d to 800,000 b/d inaugurated in December 2004. The $630m EPC contractor for Qatif North's 500,000 b/d GOSP and the 300,000 b/d offshore Abu Sa'fa field's GOSP (see below) was Snamprogetti. The $105m EPC contractor for Qatif South's 300,000 b/d GOSP was CBI Arabia a unit of Chicago Bridge & Iron which has been involved in Saudi Arabia since 1939. The contracts were awarded in March 2002. Foster Wheeler was the PMC. The project also raised the field's gas and condensate production capacity.
Qatif is said to contain 17 TCF of gas and 200m barrels of condensate. Some of the field's condensate output is being used to blend a part of its AM production to turn AEL crude oil. Qatif can produce 600,000 b/d of AL, 130,000 b/d of AM, and 70,000 b/d of AEL (38[degrees] API with about 1% sulphur). Work on Qatif has included drilling of 20 development wells. Multiple wells were drilled from a single pad.
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