The Gazelle oil and gas field is located in Block CI-202, approximately 30km south-east of Abidjan, at water depths ranging between 30m and 50m in the offshore Ivorian Basin.

The field is owned and operated by Vioco Petroleum (formerly Railto), which holds an 87% working interest, while the remaining 13% share in the field is held by state-owned oil company Petroci. The latter has an option to acquire an additional 16% paying interest in the field.

The initial field development plan (FDP) for the project was approved in December 2011 and the revised FDP was approved in October 2014. The final investment decision (FID) is expected in 2015 and the first production is anticipated in 2016.

The overall investment for developing phase one of the field development project is estimated to be $200m, $20m of which was provided by the International Finance Corporation (IFC) in 2012 and $50m is being provided by Vitol as a development loan. The remaining amount will be funded by a syndicate of banks.

Discovery, reserves and geology of Gazelle oil and gas field

The Ivorian offshore field was discovered by Esso (Shell) in 1977, with the drilling of the IVCO-12 discovery well. The IVCO-21 and IVCO 14 wells were further drilled by Esso, while the Gazelle-1 and Gazelle-2 wells were drilled by Petroci and United Meridian International Corporation (UMIC) respectively.

The field was further appraised by drilling the Gazelle-P3 ST1, Gazelle-P3 ST2 and Gazelle-P4 appraisal wells in 2012 deploying the Transocean GFS Monitor jack-up rig.

A 3D survey over the field area was completed in 1995 by UMIC and an extended 3D survey covering the entire block was completed in 2012.

The field is estimated to hold 2C contingent reserves of 92bn cubic feet of gas and 1.8m barrels of oil. Hydrocarbons at the field are located in the lower and upper Cenomanian-age sands and sandstones.

Gazelle field development plan

The initial FDP, approved in 2011, was further revised following the drilling of the new appraisal wells, results from the recent 3D seismic study and the revision of the resources report.

The development plan is based on the supply of gas directly to a new dual-fuelled independent power plant to be constructed adjacent to the field’s onshore gas processing facilities by CI-Energies.

The project facilities will include a fixed wellhead and production platform (WPP) at the offshore site, with separate 14in diameter gas and 8in diameter liquid pipelines connecting the platform to the shore. The pipelines will be designed with spare capacity to accommodate an additional 40,000bopd and 230mmscf/d in later phases.

Phase one of the project will involve the development of the Gazelle field, whereas the subsequent phases will be tied back to the recent discoveries at Block CI-202. Three production wells will be located at Gazelle, with an option to drill an additional production well in future.

Gazelle wellhead and production platform details

The Gazelle WPP will consist of a centralised, six-slot wellhead, a four-legged fixed jacket, and topsides accommodating living quarters, a helideck, a pedestal crane, a flare boom, and associated process and production facilities.

The WPP will be placed at the location of the Gazelle-1 appraisal well.

Contractors involved

The pre-front-end engineering and design (pre-FEED) studies for the project were performed by Doris, whereas the FEED studies were performed by Petrofac.

Polarcus conducted the recent 3D seismic survey, whereas the initial resources report, including the revised resources report for the field, was prepared by RPS Energy Services.