BW Energy has revamped its plan for the first phase of the Ruche development in the Dussafu Marin licence off Gabon after seeing a significant reserves hike from the larger-than-expected Hibiscus discovery that is now being wrapped into the project.

Gross reserves at Hibiscus are now estimated at 45.4 million barrels of oil following an independent assessment by Netherland, Sewell & Associates, which has lifted proven and probable (2P) reserves at the licence by 68% to 112.4 million barrels.

The reserves increase is also partly attributed to an improved recovery rate at the Tortue field that is already producing in the block.

Consequently, output from phase one of Ruche is expected to double to 30,000 barrels per day from an earlier estimate of 15,000 bpd, which will come in addition to volumes already being produced from the Adolo floating production, storage and offloading vessels at Tortue.

BW Energy now intends to shift a contemplated platform to be installed under the Ruche project about four kilometres to the west to incorporate Hibiscus resources that were found earlier this year with the successful DHIBM-1 discovery well drilled by jack-up Borr Norve.

Furthermore, a total of four production wells will be drilled at Hibiscus in addition to the two planned at Ruche, all tapping the Gamba formation, with another seven wells to be drilled under the planned second phase of Ruche.

BW Energy plans to develop the Ruche and Ruche North East finds using a new wellhead platform tied back to the floater, with first oil targeted at the end of 2021.

The revised development plan will not affect the timing of first oil from Ruche, although the investment estimate for Ruche phase one has now been increased to $445 million from a previous figure of $375 million, according to the exploration and development offshoot of Oslo-listed BW Offshore.

"Hibiscus is proving to be a discovery of equal quality and magnitude to the Tortue field. The revised development will add significantly to our production capacity and take us above the FPSO’s current nameplate of 40,000 bpd,” BW Energy chief executive Carl Arnet said in a statement.

He added the company was confident that its partners in the licence will support the revised development plan.

BW Energy holds a 73.5% operating interest in the block, with partners Tullow Oil (10%), state-owned Gabon Oil Company (9%) and Panoro Energy (7.5%).

The operator is presently in the process of drilling four production wells in the licence under the $240 million second phase of the Tortue development due on stream in the first quarter of next year.

The drilling effort is set to boost current output from the field of around 11,600 bpd to 16,000 bpd in the first half of 2020 from two initial wells and 23,000 bpd in the second half when the final two wells come online.

BW Energy also has options for two exploration wells in the licence using the Borr Drilling-owned jack-up that, if exercised, would extend the drilling effort to the third quarter of next year.

"We are considering using one or two of these options based on our successes to date and the number of prospects we have identified,” Arnet said, adding ongoing seismic reprocessing and drilling results should provide “valuable data points” by year-end.

Field Development

BW in Ruche revamp off Gabon