West Africa looks to Transform
THE hot new geological play in West ?Africa is the Transform Margin between Ghana and Sierra Leone and excitement continues to build elsewhere in sub-?Saharan Africa about the potential of the pre-salt play, transposed from Brazil.
IAIN ESAU and BARRY MORGAN London and Accra 19 February 2010 09:00 GMT
Stimulated by the major Jubilee and Tweneboa oil discoveries off Ghana and the Venus find off Sierra Leone, oil ?companies, big and small, have been ?arriving in droves in an attempt to get a slice of the Transform Margin action.
These finds have also had a positive ?effect in other West African countries, from Nigeria all the way south to Angola, where overlooked Cretaceous targets, such as Jubilee, are being sought out. The ?“Jubilee lookalike” phrase is becoming common currency.
The Transform Margin host countries that were previously deemed unpromising and initially targeted by smaller ?companies unable to enter established ?preserves in Angola and Nigeria.
Industry participants emphasise that the largely unexplored deep-water regions of the margin are far more favourable to giant ?accumulations than areas closer to the shelf and this is confirmed by successive multi-client 3D seismic surveys carried out by contractors such as Petroleum Geo-Services and TGS.
Geologists talk of finding evidence of anticlinal traps in the Apto-Albian, combination traps with ponded turbidites and stratigraphic traps associated with late Cretaceous fans. In layman’s terms, this equates to “high volumetric potential” in active kitchens from the Nigerian deep through to the Ivory Coast and beyond.
In focus is what explorationists call a new oil province extending for 1500 kilometres from eastern Ghana to Guinea with special excitement generated by sweet spots running from Benin to the Tano basin.
Brian Maxted, chief operating officer of Kosmos Energy, once described his company’s assets from north-west Nigeria to Ivorian waters as “a bad address” because of past exploration failures. However, the Jubilee find in 2007 changed perceptions and local legislators sought to respond by tightening conditions for new entrants.
Further afield, signs of a revival in activity from Senegal to Guinea-Bissau are evident in acreage acquisitions by minnows and mid-tiers in previously unfashionable addresses, though much of the pace of development depends on the will of governments to maintain political and fiscal stability.
With turmoil in Guinea, unstable regimes in place from Mauritania to the Gambia and highly prospective Guinea-Bissau described by the United Nations as Africa’s narco-state, companies may be forgiven for preferring ventures in the newly proven plays where they are told fledgling democracies can protect contracts and the rule of law.
Buccaneering Kosmos has taken its search all the way round to disputed ?waters off Western Sahara.
It is a “frontier project of choice” where the Boujdour asset hosts an untested early ?Cretaceous delta similar in size to the Niger Delta.
The risk, according to Maxted, lies in determining if, how and when hydrocarbons were charged and migrated. And this is not something every oil company is willing to risk dollars discovering.
The new “emerging basins play” can only expand exponentially as 3D and 4D modelling becomes more affordable and littoral states move to extend their exclusive economic zones from 200 to 350 nautical miles ?(370 kilometres to 650 kilometres) .
Elsewhere, according to Maxted, ?Cameroon’s “sleeping geology” offers salt basin opportunities, echoing sentiments expressed by seismic crews promoting a series of Niger Delta and Congo fan surveys designed to uncover riches previously hidden beneath the salt. Many explorationists believe West Africa could hold the equivalent of Brazil’s hugely successful pre-salt discoveries and the hunt will soon be on in countries such as Gabon to Angola to validate this assumption.
There has also been a significant resurgence of interest in upstream backwaters such as Cameroon following sizeable ?gas condensate discoveries in the Douala basin, while Equatorial Guinea continues to be a focal point for upstream players spurred on by multiple gas and liquids finds off Bioko Island.
In Congo-Brazzaville, the search is on for a second Mboundi oilfield, one of the largest onshore discoveries in Africa in recent years, while offshore, the groundbreaking Azurite project has turned a few industry heads.
Apart from its mature coastal basin, the Democratic ?Republic of Congo is true frontier territory, with its inland and rift basins in the heart of the Congo rainforest only now beginning to be of interest to junior players.
And, with reports of oil and gas finds being made in a just-completed five-well wildcat programme in the Joint Development Zone between Sao Tome & Principe and Nigeria, has this often-forgotten frontier play finally come of age?
With all this excitement about ?the Transform Margin and pre-salt ?potential one should not forget ?that Nigeria, despite its political ?problems, and Angola, will remain the lynchpins of West Africa’s upstream arena, both producing about 2 million barrels per day of crude and with significant remaining reserves, both established and yet to find.
Published: 19 February 2010 09:00 GMT | Last updated: 19 February 2010 09:25 GMT
