Kizomba Offshore Field Deepwater Project, Angola

Kizomba field, Angola

Kizomba field lies in Block 15, offshore of Angola, marking one of the first tranches of deepwater acreage offered by the Angolan Government. The development consortium is operated by ExxonMobil's subsidiary Esso Exploration Angola, which has a 40% stake in the field.

The partners also include Agip Angola (with a 20% share), BP Exploration (with a 26.67% share) and Statoil (with a 13.33% share). Sonangol, the Angolan state oil company, is the concessionaire.

Block 15 was allotted to ExxonMobil in 1994, with first production commencing in 2003 from the Xikomba field. Productions from Kizomba A, Kizomba B and Kizomba C began in 2004, 2005 and 2008 respectively.

The first production from Phase I of the Kizomba satellites project was achieved in July 2012.

Discovery of the Kizomba field

"In 2008 ExxonMobil launched phase one of the Kizomba satellite project, which included the development of two satellite discoveries, Clochas and Mavacola."

More than 2,500 square kilometres of high-quality 3D seismic data was acquired by the joint-venture partners. This was followed during 1997-99 by the first wildcat drilling programme to take place in 1,000-1,400m of water, which resulted in six discoveries. Four of the discoveries (Hungo, Chocalho, Kissanje and Dikanza) announced in 1998 make up the giant Kizomba field complex.

The reservoirs are from the middle to lower Miocene age. They consist of turbiditie debris flows deposited along the upper / mid slope. The structural trap configuration is controlled by early-Aptian salt movement, as well as lateral channel seals. The wells penetrated multiple high-quality reservoirs, giving an oil column exceeding 1,000m.

Kizomba has recoverable reserves approaching two billion oil-equivalent barrels. Other nearby fields are also planned to be tied into the Kizombo infrastructure. In 1999, the Chocalho and Xikomba fields were discovered or reappraised.

In July 2000, Esso Exploration Angola discovered another oilfield named Mondo, 370km west of Luanda. The discovery well drilled in 740m of water and encountered an oil-bearing interval, which flowed at a test rate of 4,200bpd. The well was drilled in 2,400ft of water, down to a total depth of 8,200ft.

Kizomba A deepwater development

In 2001, Esso Exploration Angola started construction on the Kizomba A deepwater development.

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Kizomba A is expected to recover approximately one billion barrels of oil from the Hungo and Chocalho fields at a target production rate of 250,000bpd. The project first began producing oil in August 2004 at a rate of more than 130,000bpd.

The field is operated by a combination of an ABB-designed 58,000t dry tree TLP and subsea completions, tied back to the Kizomba A FPSO. The dry tree unit is based on ABB's ETLP design.

The FPSO was built at a cost of more than $800m by Hyundai Heavy Industries, and the target production is estimated to require a $3.2bn investment. By the end of 2008, Kizomba A had 29 production wells and one development well.

In June 2002 Esso began construction of the Xikomba deepwater development, also on block 15. First oil from the Xikomba field was produced in late 2003, making it the first oil production on Esso-operated block 15. Production is enabled through FPSO Xikomba, which was converted from the VLCC tanker Mosocean. In May 2011, ExxonMobil announced that production at the Xikomba field will cease as reserves have depleted. About 100 million barrels of oil have been recovered from the field.

FPSO Xikomba is planned to be upgraded and relocated to Eni's block 15/06, under an agreement with SBM Offshore. The agreement was finalised in December 2011.

The refurbishment and upgrade contract for the Xikomba FPSO was awarded to Keppel Shipyard in April 2012. The project is expected to be completed in the third quarter of 2013.

Kizomba B - Kissanje and Dikanza discoveries

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In early 2003 Esso started construction of the $3bn Kizomba B project, which is also expected to recover nearly one billion barrels of oil, also at a target production rate of 250,000bpd. First oil for Kizomba B was reached in July 2005.

Kizomba B has developed the Kissanje and Dikanza discoveries in water depths of 3,300ft to 3,400ft. The project includes a combination of a surface wellhead platform and subsea wells tied back to an FPSO vessel.

The design for Kizomba B essentially duplicates Kizomba A, therefore reducing costs and cycle time.

ExxonMobil earmarked $750m for the FPSO unit, which has a storage capacity of 2.2 million barrels of oil. The unit measures 285m by 63m and stands 32m tall with a weight of 81,000t and accommodation for 100 personnel. By the end of 2008 Kizomba B had 22 production wells.

Kizomba C details - Mondo, Saxi and Batuque oil fields

The third phase, Kizomba C, is designed to develop 600 million barrels of oil from the Mondo, Saxi and Batuque fields in approximately 2,400ft of water.

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Located 145km off the coast of Angola, the Mondo field started producing oil in January 2008, while the other two fields, Saxi and Batuque, started production in August 2008.

Saxi and Batuque started production in August 2008, and between them are expected to contribute another 100,000 bpd.

The Kizomba C development features two FPSO vessels and 36 subsea wells, making it the largest subsea development operated by ExxonMobil affiliates worldwide.

Nearly $1.5bn was spent on local goods and services for Kizomba C, including contracts for in-country fabrication, logistics support, training and development of Angolan personnel.

According to ExxonMobil, suppliers played an instrumental role in the implementation of the project by providing subsea manifolds, helidecks, laydown modules, umbilicals, anchor piles and specialised turret components, which were successfully fabricated in Angola. The fabrication of the turret components was the first of its kind in Angola.

ExxonMobil's Kizomba satellite project

In 2008 ExxonMobil launched phase one of the Kizomba satellites project, which includes the development of two satellite discoveries, Clochas and Mavacola. The two fields, which are estimated to contain 250 million barrels of oil, are being developed as a tie back to Kizomba A and B production facilities.

Under the project, a total of 18 production wells will be drilled and tied-back to the existing Kizomba A and B FPSO vessels. The first phase is expected to achieve a peak production rate of 100,000 barrels a day. The second phase of the project will include development of neighbouring discoveries.

Contractors with roles in Angola's offshore oil field project

Esso Exploration Angola awarded the contract to tie back the Clochas and Mavacola fields to Saipem in July 2009. Saipem was responsible for engineering, fabrication and installation of the subsea equipment, including umbilicals, risers and pipelines.

"The partners also include Agip Angola (with a 20% share), BP Exploration (with a 26.67% share) and Statoil (with a 13.33% share)."

In August 2009 Oceaneering International was awarded the contract for supplying 34km of electro-hydraulic steel tube control umbilicals and 15km of hardwired communication link (HCL) umbilicals. The umbilicals will be used for transmitting fluids, chemicals and power from the Clochas and Mavacola fields.

The contract for the design, procurement logistics and providing the support services for the Kizomba satellites project was awarded to AMEC in September 2009. The company will execute the project in conjunction with Paragon Angola, AMEC's joint venture with Prodiaman in Luanda.

To provide subsea production equipment for the project, Esso Exploration Angola selected GE Oil & Gas on 8 September 2009. According to the terms of the contract, GE was required to provide a range of topside and subsea equipment including subsea trees, deepwater tree connectors, jumpers, manifolds, controls equipment, umbilical termination assemblies, subsea distribution units and flying leads. Equipment is installed at the FPSOs of Kizomba A and B fields. A large proportion of the equipment was produced and assembled in the Angola manufacturing and service facility of GE.

In December 2009, GE awarded a subcontract to Neptune Deeptech for supplying five subsea tree frames. GE also awarded SPT Group a subcontract to supply a subsea control system training simulator in March 2010.

Oliver Valves was awarded a £2m contract in June 2010 to supply subsea and topside valves for the satellite project.