Iran - Onshore Oil & Gas Fields Found After 1954.
Ahwaz: This is a "super-giant" discovered in 1958, when the presence of two oil producing horizons was established: the Asmari and Bangestan reservoirs. The field went on stream in 1961. Its original recoverable reserves were estimated at 10.1 bn barrels of oil and 13 TCF of gas. Gas injection was introduced at the field in 1979. The depth of its Asmari reservoir is 8,150 feet and that of Bangestan is 12,000 feet. There have been reports of reservoir problems at Ahwaz-Asmari in recent years, despite denials by the government. The oil of Asmari is 32 deg. API, and Bangestan's is 24.3[degree sign] with a high sulphur content. During test operations in October 1992, Ahwaz-Asmari produced 847,000 b/d, compared to less than 300,000 b/d in the 1980s and more than 1m b/d during the mid-1970s. Now, Ahwaz-Asmari is producing 700,000 b/d, with its capacity of 750,000 b/d to be raised to 850,000 b/d by 2002.
Ahwaz-Bangestan and Abe-Teymour's and Mansuri's Bangestan reservoirs were offered in mid-1998 as one package, a top priority project, for further development by foreign companies under a BBC. This is by far the largest and most attractive of the packages offered. Bidders for the package have included BP Amoco, Shell, Agip, Elf, Total, Lasmo and Arco (but Arco said its offer was subject to the lifting of US sanctions against American oil companies investing in Iran). During NIOC's London presentation in early July 1998, it was said the three Bangestan reservoirs had 65 bn barrels of oil in place, of which 10% was thought to be recoverable. They require a 600 MCF/day gas injection system, or a combination of gas and water injection systems. The gas is to be piped from South Pars or the onshore gas fields of Shanul, Varavi and Gardan (near Assaluyeh) which NIOC is developing on its own. NIOC has asked BP Amoco also to bid for South Pars Phases 4 & 5, in competition with Shell and other companies, so that the gas from this project is partly supplied to the three Bangestan reservoirs (provided that BP Amoco wins the relevant BBCs).
During October 1992 tests Ahwaz-Bangestan only produced 132,000 b/d. But now it is producing 150,000 b/d. Under the proposed BBC for the three reservoirs, Ahwaz-Bangestan's capacity is to be raised to 300,000 b/d within a five-year period. Mansuri's capacity will rise from 75,000 b/d to 120,000 b/d. Abe- Teymour's will be raised from 40,000 b/d to more than 100,000 b/d. NIOC's objective to boost total Ahwaz production to more than 1.5m b/d, eventually, may be achievable with the help of foreign capital and technology.
Binak, a small field discovered in 1958 near the mouth of the Persian Gulf, went on stream in 1967. Its oil in place has been estimated at more than 400m barrels of 30 deg. API. The field's depth is 10,440 feet. Now it is producing 30,000 b/d with its capacity to stabilise at 50,000 b/d in the next decade. During test operations in October 1992 and August 1994, Binak produced 47,000 b/d. This field was to begin receiving gas injection as from April 1996.
Bibi Hakimeh, found in 1961 in Boyer Ahmad province, has two oil reservoirs and a large gas cap. It went on stream in 1964. Its oil reserves have been estimated at 2.5 bn barrels of 29.9 deg. API with 1.6% S and gas reserves at 8 TCF. Its depth is 4,570 feet. During October 1992 tests the field produced 144,000 b/d. Its output now is 130,000 b/d and is set to reach 150,000 b/d by 2000. EOR started up in 1979. A $100m, 270 MCF/d gas injection project was inaugurated on Dec. 2, 1996, by then President Rafsanjani, raising recoverable oil reserves by more than 1 bn barrels.
Ramshir, discovered in 1961, was confirmed in the following year with a second oil well. It was the first in onshore Iran to be drilled purely on seismic evidence. But it has remained small by Iranian standards and its oil reserves have been estimated at 120m barrels of 27.6 deg. API. Its depth is 8,750 feet. During October 1992 tests, the field produced 24,000 b/d. Gas injection at the field began in 1996.
Kharg was discovered in 1962 as an onshore extension on Kharg island of the offshore Doroud field (see Gas Market Trends). Its oil in place has been estimated at around 1 bn barrels of 31.6 deg. API. Its gas reserves are estimated at about 6 TCF. The field's depth is 10,900 feet.
Mansuri, a seismic structure in the plains at the mouth of the Gulf, was confirmed in 1963. It went on stream in 1974. Its oil reserves have been estimated at 650m of 28.4 deg. API. Its gas reserves are said to be 600 BCF. Its depth is 7,100 feet. It is producing 50,000 b/d. The field's Bangestan reseroir, together with the Bangestan reservoirs of Ahwaz and Abe-Teymour, are to be developed by a foreign company under a BBC, with the bidders having included BP Amoco, Shell, Agip, Elf, Total, Lasmo and Arco. Mansuri's capacity will be raised to 120,000 b/d within five years.
Karanj-Parsi: Two connected oilfields with a joint production system, Karanj- Parsi's output now averages 195,000 b/d. The output capacity is to be raised by 11,000 b/d later in 1999 with the completion of a gas reinjection system. The capacity should reach 360,000 b/d within the next five years. Karanj, found in 1963, also produces gas. A gas injection project at Karanj was completed in 1995. The field has a 650-metre thick oil column with a gravity of 33.9 deg. API and 1.2% S. It went on stream in 1965. Its oil reserves have been estimated at 1.65 bn barrels, with gas at about 3.5 TCF. During October 1992 tests, Karanj produced 196,000 b/d, according to NIOC. Journalists present at the demonstration contested that figure. Parsi was found in 1964 with a large gas cap near Karanj. Its reserves have been estimated at 3 bn barrels of 34.2 deg. API oil and 9 TCF of gas. During October 1992 tests it produced 80,000 b/d. But subsequently production was suspended, because of reservoir damage.
Marun, one of the most prolific oilfields in Khuzistan found in 1964, is a major Asmari producer, 9,400 feet deep delineated by seismic work. It has a thick oil column and a high-pressure gas dome. The oil is of 32.5-33 deg. API gravity. Its reserves have been estimated at about 9.5 bn barrels of oil and 45 TCF of gas. Gas injection was introduced at the field in 1980, with EOR work having begun after Marun's peak production of 1.3m b/d in 1977. In 1994 it was said Marun's production had fallen to 450,000 b/d but NIOC denied this. The field is producing 520,000 b/d, up from 550,000 b/d in 1995, with capacity to expand to 600,000 b/d by 2001. A 40 MCM/day gas injection system fed from the Aghar and Dalan gas fields was completed in mid-1996. The gas flow is to be maintained for 24 years by which time the field would be depleted. Injection levels may be increased in the coming years to keep production stable. During October 1992 tests, the field produced 560,000 b/d.
Rag-e-Safid, found in 1964 as a result of seismic confirmation of a surface structure at the mouth of the Gulf, is producing 160,000 b/d, as capacity. Rag-e-Safid was first judged to be a gas field. But subsequently an oil column was found. Its reserves have been estimated at 2.4 bn barrels of 28.6 deg. API and 15-20 TCF of gas. The field's depth is 7,230 ft.
Sarakhs, in the north-east of the Central Iranian Basin straddling the border with Turkmenistan, is one of Iran's giant gas fields found in the 1960s. Its recoverable reserves are said to be as large as 100 TCF. It is among the main gas producers in Iran. In late 1997, NIOC completed a $103m development programme for Sarakhs, having drilled 30 wells. More development work is being done - in view of a major gas shortage in the Mazandaran, Khorasan and other northern provinces - for its output to rise from 11 BCM/year now to 14.6 BCM/year by 2001.
The Mand Mountain fields, south-east of Bushehr and extending to Khairrabad to the south-west, were discovered in 1964 and 1965 by the consortium. In December 1988, then oil minister Aghazadeh said they had recoverable oil reserves of about 10.2 bn barrels. But nearly 10 bn barrels of these consist of very heavy crudes, 14-16 deg. API in one zone, and 8[degree sign] in another. The remaining 200m barrels east of Behbehan are light oils of over 37[degree sign] which can be extracted at the rate of 40,000 b/d within about three years of development. Major gas fields were also discovered in and around the Mand mountains, though their reserves data were not announced. (The Mand geological formations, similar to those of Khuzistan, were neglected because the Western operators considered them to be uncommercial. Some of the Mand reservoirs lie in limestone layers where recovery is limited by permeability). One of the fields developed there by NIOC, Zaregheh, was brought on stream in October 1992 at the rate of 2,000 b/d of 12 deg. API oil. Output has risen to 11,000 b/d.
Kupal, discovered in 1965 in the central area, has two reservoirs with 34 deg. and 35 deg. and 1.4-1.8% S oil. It was put on stream in 1971. During October 1992 tests it produced 60,000 b/d, according to NIOC, but since then its output has declined considerably. An EOR system was installed in 1996 but the output remained relatively low. Its reserves have been estimated at 1.1 bn barrels of oil and 5.5 TCF of gas at a total depth of 10,500 feet.
Par-e-Siah, a small field found in 1966, has a short oil column beneath a gas cap. It was brought on stream in 1970. Oil is 38.2 deg. API with virtually no sulphur, with reserves estimated at 50m barrels at a depth of 4,250 feet. (continued next article)
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|Publication:||APS Review Gas Market Trends|
|Date:||Apr 5, 1999|
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