Bahr Essalam Gas and Condensate Field, Libya

Bahr Essalam

The Bahr Essalam gas and condensate field is located within Block NC41 in the Mediterranean Sea, approximately 110km from Tripoli, Lybia.

The offshore gas and condensate field is owned and operated by Mellitah Oil & Gas (MOG), an equal joint venture (JV) between Eni, and National Oil Corporation (NOC), a Libyan state-owned oil company.

The field started production in 2005 as part of the Bahr Essalam Phase I project. MOG has now proposed the Bahr Essalam Phase II project, which will involve the development of the field's unexploited areas.

The Libyan offshore field currently produces approximately 600 million standard cubic feet a day (MMscfd) of sales gas and approximately 30,000bbl/d of condensate.

Bahr Essalam gas and condensate field phase one development details

Phase one involved the development of the C Western area and the C Central B area, with the former incorporating 11 subsea wells and the latter incorporating 15 platform wells.

The production from the former area is conveyed to the Sabratha process platform, located within the C Central B area, via two subsea flowlines.

Bahr Essalam gas and condensate field phase II development

The Phase II project primarily involves the development of the C Central A area and the C East area, and upgrade of the Sabratha platform.

At the C East area, ten wells will be developed through two clusters, and the subsea facilities will be connected to the existing riser and J-tubes of the Sabratha platform.

The C Central A area will incorporate three wells, of which one has been pre-drilled. The two undrilled wells will be developed through a single cluster and connect with the existing riser and J-tube of the Sabratha platform, whereas the CC09 pre-drilled well will connect a dedicated in-line tee preinstalled on the existing gathering lines that connect the C Western area's subsea facilities to the Sabratha platform.

Major facilities at the project will include production pipelines, piggy-backed service lines, two subsea isolation valve (SSIV) structures, and two SSIV umbilicals. The offshore installation works for the project will start in 2017 and are expected to be completed in 2018.

Gas and condensate processing facilities

The gas produced from the field is treated on the Sabratha platform for separation and dehydration, and further transported via a 36in-diameter pipeline to the onshore Mellitah plant, for final treatment.

"The field started production in 2005 as part of the Bahr Essalam Phase I project."

Following the final treatment, the gas is supplied to the local market and also exported to Italy via the Green Stream compression station and 540km-long, 32in diameter sea line.

The condensate is directly pumped and conveyed through a 10in diameter pipeline to Mellitah for further treatment and export.

The 25,000t Sabratha platform is equipped with the preliminary gas separation and dehydration facilities, an 800t fast moving workover rig (FMWR), a 1,800t living quarters for 117 people, a heli-deck, and a 117m-long flare boom weighing 718t.

The onshore Mellitah complex is equipped with separate facilities to process oil and gas produced from the Bahr Essalam field and the onshore Wafa field. It is equipped with three trains for gas and two trains for condensate to facilitate treatment of gas and condensate conveyed from the Sabratah platform. The five trains have a dedicated capacity to treat 695MMscfd of sales gas, 31,000bbl/s of liquids and 450t of solid sulphur.

Contractors involved

The engineering, procurement, construction and commissioning (EPCM) contractor for the subsea production and transportation systems, and the production platform under phase one was Saipem, who worked in collaboration with Rosetti Marino.

Maccaferri supplied its proprietary SARMAC bituminous mattress for the protection of the subsea pipelines under the Phase I.

Technip has been awarded a contract worth more than $500m to provide the EPCM services as well as design and pre-commissioning services for the subsea facilities under phase two. Technip will deploy its Deep Energy pipelay vessel, Deep Arctic diving support vessel, and G1200 S-Lay vessel, to perform the installation works.