Hibiscus and Ruche Development, Gabon

The Hibiscus and Ruche development involves the development of the Hibiscus and Ruche fields located offshore Gabon within the Dussafu licence.

BW Energy Gabon, a subsidiary of exploration and production company BW Energy, serves as the operator of the licence.

The Ruche field was initially planned for development when the block was declared commercial, and the exclusive exploitation authorisation (EEA) for Ruche was granted in July 2014. The field development plan (FDP) was approved by the Direction Général de Hydrocarbures (DGH) in October 2014.

The discovery of significant oil reserves in the Hibiscus area in 2019 led to the revision of the Ruche phase one development to include the Hibiscus field, which is the largest discovery made in the licence.

The project is being developed in phases with the first phase investment estimated at approximately $450m. First oil production from phase one of the development was achieved in April 2023.

The Hibiscus and Ruche development is expected to increase the overall oil production from the area by up to 40,000 barrels of oil per day (bopd).

Location and ownership of the Hibiscus and Ruche development

The Hibiscus and Ruche development is situated in the Dussafu licence, within the 850km² Ruche Exclusive Exploitation Area (Ruche EEA). The average water depth at the project area is 116m.

The fields are located approximately 20km north-west of the Tortue Field, which is within the same licence.

Harvest Natural Resources (Harvest)’s wholly owned subsidiary Harvest Dussafu previously held a 66.67% interest in the block and served as operator. The company initially acquired a 50% interest in the field from Sasol Petroleum West Africa in December 2007 and a further 16.67% interest from Perenco in late 2008.

Independent exploration and production company Panoro Energy held the remaining 33.33% interest in the block and had earlier acquired Premier Oil’s 25% share in early 2008 and 8.33% of Perenco’s share in late 2008.

BW Energy Gabon acquired a 66.66% stake in the Dussafu licence from Harvest in April 2017. The company acquired a further 25% working interest through a definitive sale and purchase agreement with Panoro Energy subsidiary Pan-Petroleum Gabon in the same month.

The ownership interest of the Dussafu licence is currently shared between BW Energy Gabon (73.5%), Panoro Energy (17.5%), and Gabon Oil Company (9%).

Reserves of the Hibiscus and Ruche Development

The project is expected to recover gross reserves of approximately 47.6 million barrels.

Discovery and drilling activities within Dussafu block

The Ruche C field was discovered in 1981, which flowed at an initial rate of up to 2,730bopd from the Dentale Formation. The Ruche D field was discovered in 1995 and encountered a 17m oil column in the Gamba sandstones.

The Dussafu Ruche Marine-1 (DRM-1) exploration well was drilled in April 2011 and completed in October 2011. The well was drilled by the Transocean Sedneth 701 semi-submersible drilling rig to a depth of 3,463m. It encountered 19m of pay in a 28m oil column within the Gamba formation and 10m of pay in the Middle Dentale formation.

The well was appraised by a sidetrack well DRM-1ST1 located 1.2km south-west of DRM-1. It encountered 6m of net pay in a 15m oil column in the Gamba. A further sidetrack well DRM-1ST2 located 890m north-west of DRM-1, encountered 12m of net pay in a 21m oil column.

The drilling of the Dussafu Tortue Marin-1 (DTM-1) exploration well within the Tortue prospect started in November 2012. Drilled to a vertical depth of 11,260ft, it encountered 42ft of pay in a 72ft oil column within the Gamba formation. The well also encountered 123ft of pay in stacked reservoirs within the Dentale formation.

A sidetrack well located more than 1,800ft from the DTM-1 well was drilled to a depth of 11,385ft in the Dentale formation to appraise the DTM-1 well. It encountered 65ft of oil pay in the primary Dentale reservoir. The wells at the Tortue field were drilled by the Saipem Scarabeo 3 semi-submersible drilling rig.

The DHIBM-1 exploration well in the Hibiscus Updip prospect was completed in August 2019. The well encountered approximately 21m of oil pay in a 33m hydrocarbon column in the Gamba formation. It was drilled to a total depth of 3,538m at water depths of 116m. The appraisal side-track (DHIBM-1 ST1) also encountered 26m of oil pay in the Gamba formation.

The Hibiscus North exploration well (DHBNM-1) was spud in July 2021 and discovered oil in August 2021. The well is located at a water depth of 115m, approximately 6km north-northeast of the Hibiscus discovery.

The well encountered approximately 13.5m of an oil-bearing reservoir in the Upper Gamba sandstone at a depth of 2,794m. It also encountered oil in the deeper Dentale formation.

The DHIBM-2 appraisal well was drilled to further evaluate the Hibiscus field but did not encounter any hydrocarbons.

The exploration and appraisal drilling operations at the Hibiscus and Ruche fields were carried out by the Borr Norve jack-up rig.

Hibiscus and Ruche field development plan

The Hibiscus and Ruche fields are to be developed through 12 wells. Six horizontal production wells are planned for the initial phase of the project to exploit the Gamba reservoir. Four out of the six wells will target the Hibiscus field while the remaining two wells will target the Ruche field.

Drilling operations for the first production well (DHIBM-3H) commenced in January 2023 from the BW MaBoMo production facility on the Hibiscus field. The drilling operations were completed in early April 2023 with the well reaching a total depth of 3,883m.

The oil produced from the Hibiscus and Ruche development is transferred by a 20km pipeline from the BW MaBoMo production facility to be processed on the BW Adolo floating production storage and offloading (FPSO) vessel, along with the existing Tortue field production, and offloaded to oil tankers.

The project is expected to add 30,000bopd upon completion of all planned wells, which is expected in early 2024. A gas lift compressor is being installed at the BW Adolo FPSO to support future activities. The completion of start-up activities and stabilisation of production from the DHIBM-3H well are also progressing.

Infrastructure details of the Hibiscus and Ruche fields

The BW Adolo FPSO has a storage capacity of 1.35 million barrels of oil with a processing capacity of 40,000 barrels per day (bpd). The FPSO has a gas handling capacity of 18 million standard cubic feet of gas per day and a water injection capacity of 60,000bpd.

The BW MaBoMo was earlier known as the Hibiscus Alpha jack-up drilling rig, which was repurposed into an offshore production facility with 12 well slots.

Contractors involved

Borr Drilling was awarded a contract in December 2021 to drill four wells for the Hibiscus and Ruche development.

The contract to convert the Hibiscus Alpha jack-up rig into an offshore production facility was awarded to offshore construction and fabrication company Lamprell in October 2021.

US-based engineering company Zentech was responsible for the front-end engineering design (FEED) study and the subsequent shipyard construction specification preparation contract for the Hibiscus Alpha rig conversion.

Offshore engineering solutions company Aquaterra Energy was contracted for the procurement, engineering, manufacture, installation, and commissioning support of multiple conductor tensioning units for Hibiscus Alpha.

TechnipFMC, a technology provider for the oil and gas industry, was contracted to install the 20km pipeline between the BW MaBoMo production facility and BW Adolo FPSO.

In May 2018, BW Energy entered a bareboat charter agreement with BW Adolo, which commenced operation at the Dussafu field in September 2018.