A British a petroleum geologist has raised fresh questions about Senegal’s Sangomar oil reservoir extending into Gambian waters.
Henk Kombrink is a petroleum geologist at Lloyd’s Register with 15 years of experience in regional geological mapping across Northwest Europe. He is currently the technical project manager of an oil and gas authority-funded project where geological maps and data sets are being produced for the whole of the UK continental shelf.
Writing in the latest edition of the Geo Expro, a magazine with a strong focus on the subsurface aspects of the global oil and gas industry and the energy transition, Kombrink stated that recently published maps of the Sangomar field offshore Senegal depicting the southern boundary of the accumulation exactly lining up with the maritime boundary between Senegal and The Gambia, suggesting that there is no extension into The Gambia should raise eyebrows.
“It just looks odd to see an oilfield boundary lining up with what is essentially a human-derived line. That’s why I published a story last year about the possibility that a small part of the Sangomar field does extend into The Gambia.”
He reminded that during the initial exploration and appraisal of Sangomar between 2014 and 2020, companies involved in exploring the area were all of the opinion that Sangomar did indeed extend into The Gambia. “The boundary took a much more natural shape at the time. The implications for a country without commercial hydrocarbon production were substantial: There was considerable optimism that The Gambia might soon realise its first oil revenues. And with FAR drilling two wells – Samo-1 (2018) and Bambo-1 (2021) – in Gambian waters, there was real excitement that things would materialise,” he recalled.
However, after the drilling and completion of these two wells, both of which were targeting reservoirs thought to be within the possible extension of the Sangomar field, the mood turned around quickly. FAR reported that both wells had been unsuccessful and soon after relinquished their licence after failing to attract new joint venture partners.
However, Kombrink contended: “The main reason for FAR to discount the Bambo-1 well results was the observation that the quality of the Sangomar-equivalent section encountered in the well was too poor to be regarded as a reservoir. This may be true, but that doesn’t mean it justifies the conclusion that all strata representing the extension of Sangomar into The Gambia have the same poor reservoir properties. There are plenty of examples of oil exploration wells that “undiscovered” a field before the next well hit the jackpot.”
On the redrawing of offshore block boundaries by The Gambia Government in 2023, he pointed out that while two of the A2 block’s corner coordinates remained unchanged, the northern boundary was shifted more than a kilometre to the south, resulting in the Bambo well falling outside the new block limits.
“This”, he argued, “raises several questions. What justified this redefinition, which resulted in the Bambo well being excluded from the block? The result is a 1.1 km strip of marine territory between the A2 block and the national border that coincidentally corresponds to where any transboundary Sangomar extension would logically lie. Is this shift unrelated to administrative housekeeping? Or does it hint at an intentional move to delink the Bambo data from future licensing rounds and potential resource claims?”
Mr Kombrink said until there is comprehensive disclosure of the reservoir data, and an assessment of reservoir quality based on seismic inversion results, the possibility of a Sangomar extension into Gambian waters must remain an open and serious question.
Reaction
Asked to react to Mr Kombrink’s concerns, a Gambian engineer and geologist who took part in exploration and well drilling in The Gambia said his arguments “are solid and grounded in both history and geology”.
Speaking on condition of anonymity, he stated: “I was working with the team as the Samo-1 was being drilled and I can tell you it was full of optimism until target depth was reached. The results were incredibly devastating and the only way they could be false would be if this is the biggest oil and gas conspiracy since oil was first discovered in Texas.
“Notwithstanding, we can agree that there is absolute truth in the way things happened leading to the new block and field demarcations in The Gambia and Senegal respectively. A worthy note is the fact that Woodside Energy who are now the principals on the Sangomar development were the leading bidders for the adjacent blocks in The Gambia at a time.
“However what is happening right now in my opinion is more a case of expediency rather than a conspiracy. Unfortunately also, recent developments in the industry and the global economy have made The Gambia less attractive for exploration which further allows this expediency next door to happen freely.”
