IRAQ - The Main Fields In The North.
Kirkuk once sat on a lake of oil. Crude oil still bubbles up to the surface in some places, feeding fires which have been smouldering since before the Babylonians used the oil tar to pave the roads to their palaces. But the lake is running dry.
Kirkuk: After 71 years of pumping oil, the Kirkuk group of fields now account for less than 10% of Iraq's proven reserves of 112.5 bn barrels. The fields' production relies heavily on gas and water injection, which makes Kirkuk oil more expensive to produce and more vulnerable to more than a decade of under-investment. The fields were not damaged during the war, despite fears that the Baathist regime would set fire to the wells. But there was some looting of IPC offices after most Baathist officials fled just a week after the fall of the regime in April 2003.
Oil production from all the northern fields fell from 1.2m b/d before the early 1991 war to 700,000 b/d, rising to 1m b/d by 2001. At times since then the output has risen to 1.1m b/d. No new wells had been drilled in the north since the UN sanctions were imposed in August 1990.
Saybolt, a Dutch oil consulting firm contracted by the UN to oversee Iraq's oil exports and study the fields years before the 2003 war, had forecast a 4-8% decline in total production. Wells were watering out and the ability of the industry to treat crude oil prior to export was limited because crucial spare parts were yet to be installed. Below are profiles of the main northern fields and structures yet to be developed by foreign companies:
Kirkuk and its satellites constitute the main oil production system in the north. Kirkuk was the first oil discovery in Iraq by the foreign concessionaire, IPC, in 1927. The main field went on stream in 1934. (IPC - originally known as Turkish Petroleum Co., owned by BP, Shell, Total, Exxon, Mobil & Partex - was nationalised in June 1972). In mid-1990 the Kirkuk group's output exceeded 1.6m b/d and its recoverable reserves were estimated at 10 bn barrels, mainly of 36 deg. API oil with 2% sulphur and some of the 44 deg. range. In March 1991, after Kurdish rebels attacked Kirkuk city, the Baathist authorities set some of the field's wells on fire. But the pipeline linking the field to Turkey was kept intact.
Shell in January won a contract to assist Explorational Consultants Limited (ECL) of the UK's on an integrated reservoir study for the Kirkuk group. Shell has been keen to gain a foothold in Iraq despite the uncertain political situation and the insurgency. Shell is already offering free assistance to the Oil Ministry to help it draw up a gas masterplan. The major is also training local oil sector employees.
The Kirkuk system now can produce up to about 800,000 b/d, compared to 930,000 b/d in April 1999 and 600,000 b/d in 1997, but its output now is less than 500,000 b/d. It has an installed capacity of 1m b/d, though this is not sustainable for more than two months. The fields produce from two of group's four domes, Avanah and Baba. The third dome, Khurmala, is being re-developed by a Turkish-led consortium so that its production capacity is raised from 6,000 b/d to 100,000 b/d (see OMT).
The Kirkuk reservoirs have been damaged by saline water incursions and the oil column has shortened. It was said in 2001 that, unless NOC got the needed equipment, the production system could fall to 600,000 b/d or less within two to three years. Water injection has been used extensively at Kirkuk since 1961. It was said in April 2003 that, with wells then suffering from rising water levels at Baba and Avanah, Kirkuk output levels could only be controlled by a rotation of wells into and out of production. NOC in 1998 had to shut in 25 wells at Kirkuk because they were producing corrosive water. NOC needed advanced equipment and spare parts for fresh water injection into the field - as well as drilling materials, flowlines, manifolds, separators, wet crude facilities, gas compressors and telecommunications and control systems - in order to maintain production. It also needed to drill replacement wells, improve the crude oil processing plant, and other installations.
Khurmala was being developed, together with the nearby Humreen field, when the Jan/Feb. 1991 war began. After the Kurds' rebellion in March 1991, Kirkuk became a key issue in autonomy talks between Baghdad and the Kurdish parties KDP and PUK, with the latter two now insisting that the region be re-defined as part of Kurdistan. The Baathist regime made Kirkuk part of an Arab province called Tamim.
Kirkuk has had one of the largest oil accumulations in the world. It is a very long and sinuous anticline, forming one of the Zagros foothill's asymmetric folds, with superficial thrusting in Lower Fars cap-rock Fms. It produces oil from an Asmari limestone of the Eocene-Oligocene-Lower Miocene age. It also has oil accumulations in an Upper Cretaceous fractured Shiranish limestone and a Middle Cretaceous Qamchuqa limestone. The Lower Fars limestone is shallow in crestal wells about 450 metres deep, and its Qamchuqa layer is only about 1,250 metres deep. A recovery system based on water injection was installed in 1961 and a modern EOR programme was planned in 1990. But the fields appear to be in irreversible decline. Since 1992, NOC has been re-injecting fuel oil into the Baba and Avanah domes. In 1990 it had a total of 269 wells, including 71 production wells.
Humreen, a nearby structure south-east of the Baiji industrial zone, was partly developed before the war , with evaluation wells drilled and its reserves are in the 200-500m barrel range in a Qamchuqa limestone, with the first discovery well having tested 10,000 b/d of 32 deg. API oil. The small Injana field, close to Humreen, was discovered by IPC. Injana 5, drilled in 1958, had 33 deg. API oil in Kometan carbonates. NOC's plannned for Humreen, Khurmala and the nearby fields of Galabat and Taq Taq to have a combined capacity of 160,000 b/d of light oil. The project was offered in the 1990s for a SC. Now Humreen and its Galabat and Taq Tag satellites are being developed under an EPC job to produce 60,000 b/d (see OMT).
Bai Hassan is a major field near Kirkuk found in 1953 and brought on stream in 1960 by IPC. It had proven reserves of 2 bn barrels by 1990. It produces 32-34 deg. API oil from an Asmari limestone, composed of a reefal Fm of the Eocene-Oligocene-Miocene age, partly equivalent to the Asmari of Iran and lying below a Miocene Lower Fars cap rock. Additional production is possible from the Upper Cretaceous Shiranish limestone (27 deg. API oil) and the Middle Cretaceous Qamchuqa limestone. The sulphur content of Asmari oil is 2.3% and that of Shiranish is nearly 4%. The field has a large gas cap. In 1990 it had 84 wells, with 56 producers. Bai Hassan can produce about 100,000 b/d and has a short-term capacity of 200,000 b/d. Tatneft in 2001 began work on drilling 45 new wells at Bai Hassan and Saddam fields, to the south, under a SC awarded to Zarubezhneft in 1999 and approved by the UN in late 2000.
Khabbaz, in the same province, was developed and brought on stream in March 1994 by NOC. It was found in 1976 by Iraqi geologists. The field's reserves were then put at about 3 bn barrels, lying in three Fms: the Jerribe/Oilgacin, with 36 deg. API oil in a 130-metre column at a depth of 1,907 ft; Upper Qamchuqa, with 29 deg. oil in a 125-metre column at a depth of 2,687 ft; and Lower Qamchuqa, with 42 deg. oil in a 175-metre column at a depth of 2,912 ft. Its development, begun in 1987, was interrupted in 1990 by the Gulf crisis. Now it has 30 wells and a 70 MCF/d compression and dehydration plant, plus a pipeline linking it to the main export network. Technip Geoproduction of France worked on it until August 1990. NOC was in 2001 planning to drill replacement wells at Khabbaz and install a wet oil treatment facility to inject fresh water into the field. Khabbaz can produce about 25,000 b/d of oil and 45 MCF/d of gas.
Jambur, near Kirkuk, was found in 1954 by IPC. Oil comes from Middle to Lower Miocene marly/oolitic Jerribe and Euphrates limestones at 5,500 ft, interbedded with anhydrite under Lower Fars cover. Production is enhanced by fractures, with oils of 38-47 deg. API and 1.3% S. A Qamchuqa Fm contains gas at 12,500 ft. The field went on stream in 1959. It has 50 wells to produce 75,000 b/d.
Koysinjaq is a small oilfield in the Erbil region in the Kurdish north. According to Petroleum Argus on Nov. 18, 2002, the field was partly exploited by Kurds linked to the PUK, with up to 6,000 b/d extracted from an exploration well. The crude oil, about 30 deg. API, was trucked to a former sugar factory in Sulaymania (PUK's area of control), where it was processed into gasoline and benzene for local consumption. Argus said the Baathist authorities were sending oil products to the region to discourage the Kurds from unplugging other wells in the north.
TPAO said in late 2001 it was to begin exploring for oil in the northern area controlled by the Kurdish Democratic Party (KDP) of Massoud Barzani. TPAO's then CEO Kenan Veziroglu said: "We will seek oil in 10 different places in the Barzani region".
Oilfields in the north-east - Qamar, Qara Choq and Khashm Al-Ahmar - have been appraised and allocated for development for a total capacity of 120,000 b/d. This group was offered in 1995 for a single SC.
Five major north-eastern gas fields were then earmarked for development on a fast track under one SC, for 775 MCF/d of gas exports to Turkey within three years from the end of the UN embargo. These fields and their proven gas reserves are as follows: Mansuriya (3.28 TCF); Chemchemal (1.8 TCF), which until 1990 used to produce more than 7 MCF/d of gas and 63 deg. API condensate, discovered in 1953 and lying east of Kirkuk in fractured Upper Cretaceous Shiranish carbonates and Kometan limestone (Turonian); Anfal (1.76 TCF); Khashm Al Ahmar (1.41 TCF); and Jeria Pika (918 BCF). On May 10, 1997, an initial deal was signed in Baghdad between the Baathist and Turkish governments to develop these fields, lay a 300 km, 10 BCM/year pipeline from the Iraqi border to south-eastern Turkey, with Iraq to extend to the border its central gas pipeline which runs from the south to the north, and build a related gas liquids plant at Turkey's oil terminal of Ceyhan. Talks on the project were resumed in September 2001. (Before its invasion of Kuwait, Iraq used to export about 400 MCF/d of associated gas from the south to that emirate through a pipeline opened in April 1987).
Other fields in the north include: Demir Dagh, which produced 11 MCF/d of gas and 43 deg. API condensate, found in 1960 and lying in fractured Shiranish carbonates above 22 deg. API oil; and Pulkhana, found close to Jambur in 1956, with oil of 35 deg. API and 2.7% sulphur present in the Euphrates reservoir of Lower Miocene age, and of 28 deg. API oil present in the fractures of the Upper Cretaceous Shiranish limestone.
The Mosul fields, in N-W Iraq, lie in an area stretching to the Syrian and Turkish frontiers. This has been claimed by Turkey and partly contested by the Iraqi Kurds. Now the Mosul fields can produce about 20,000 b/d. NOC has been in charge of the Mosul fields. Some fields lie in trends continuing into Syria - like the Akaz oil/gas find made in 1993 by Iraqi geologists - and into Turkey. One structure extending into Syria's Deir El Zor is rich in sweet oil.
Ain Zalah, found in 1937 by IPC's Mosul Petroleum Co. (MPC), has produced since 1955 from Cretaceous carbonates: the fractured Shiranish marly limestone of the Maestrichtian/Campanian (Upper Cretaceous) age where 32 deg. API, 3% sulphur oil has been depleting; and the Middle Cretaceous Qamchuqa Fm (29 deg. API oil, 2.6% S). The reservoirs are connected, the upper one (5,200 ft) being slowly charged through fine fractures in the intervening tight succession from the lower Fm (6,500 ft). The field went on stream in 1951. In the 1970s it was linked to the Kirkuk-Ceyhan pipeline as in the case of other Mosul fields. It has 28 wells, including 15 producers, with an output capacity of 10,000 b/d.
Butma is small S-E of Ain Zalah found in 1952 by MPC. Oil (30 deg. API) comes mainly from a fractured Shiranish Fm, with 35 deg. oil from a Triassic Kurrachine limestone. It went on stream in 1953, and its Middle Cretaceous reservoir proved to be water-wet. It has 17 wells but only one producer.
Qayara, only 650 feet deep, is one of three anticlinal structures in the same fold-axis south of Mosul. The other two are Nejmah and Qasab. Another field, Jawan, is a separate but parallel structure. The four contain large accumulations of very sour oil (11-18 deg. API with 6.5-8% S) in Lower Miocene limestone, partly equivalent to the Asmari, and in the Upper Cretaceous "Pilsner" limestone (16-18 deg. API). The oil by 1990 was not yet refinable. Only a limited volume was used for asphalt and other heavy residues. Qayara was found in 1927 by British Oilfield Development before Mosul was taken over by MPC. Now it has 50 wells, including 33 producers. The fields were offered for a combined 120,000 b/d production rate under a SC.
Alan is small found in 1954 by MPC near Mosul, with 33-34 deg. API oil in Sargely and Kurrachine carbonates. Sassan is another small but non-commercial find made in 1956 by MPC close to Ain Zalah, with 40 deg. API oil lying in Shiranish argillaceous fractured carbonates and the Albian Jawan lagoonal fractured carbonates. Safaya, found in 1974 by Iraqi geologists and brought on stream in 1978, straddles the Iraqi-Syrian border and extends into what is known in Syria as Souedie. It has produced oil from the Senonian-Turonian "Massive Limestone" (about 22 deg. API). In 1989 it was reported to have light oil and gas found in Liassic (Triassic) Butma carbonates. Safaya has 39 wells, including 11 producers.
Gas/condensate fields discovered in the north-west of Iraq in recent years, together with several gas/condensate fields found in the south, were to be developed exclusively by the Oil Ministry's companies, with SCOP as main contractor. They were to include fields with large gas caps, or with high gas/oil ratios providing big quantities of dissolved gas. Big investment was being planned for this, with the gas to feed petrochemical ventures which the Baathist government intended to launch. By early 1990, these fields had become important in efforts to lighten Iraq's mix of export crude oils, as neighbouring GCC states had begun to consider.
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|Publication:||APS Review Downstream Trends|
|Date:||May 2, 2005|
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