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Meeting Report

Meeting report

Africa : The Elephants of the Future5th PESGB / HGS African Conference

These annual Conferences typically provide a rich offering of concise technical presentationsin a logically-organized programme and are aimed at working geoscientists andprospect generators.This year’s two-day Conference seemed to capture the current high levels of

activity and expectation in the industry, which was reflected in an attendance of nearly 400. The first day’s programme focused on the Mediterranean and East African frontier basins in the morning

and North Africa in the afternoon. An initial regional review by Pardon and Collins (Fugro-Robertson)established the presence of multiple oil- and gas-prone source rocks and stacked reservoirs throughoutthe coastal basins of Kenya, Tanzania, Mozambique and western Madagascar with a commensurate highpetroleum potential. This was well illustrated by a review of the Rovuma Basin by Pilskøg et al. (Hydro) thatdemonstrated potential in the pre-rift Karoo on the Ibo High and in well-developed syn-rift and passivemargin megasequences. Matchette-Downes (EAX) discussed the potential of the Seychelles plateau. Thetalk sought to demonstrate a geochemical tie between subsurfce oil staining reported in a well, tar ballsfrequently seen on beaches, oils from both Tanzania and Kenya, and even oils from the Bombay High area,western India.

Cassie (formerly of Hardman) described the company’s exploration in the Ugandan sector of LakeAlbert, which has led to the first significant oil discoveries in the East African Rift System. The first twowells flowed up to 820 and 4,200 b/d respectively from multiple oil columns in stacked Neogene lacustrineturbidites in faulted hanging-wall structures. Particularly interesting was their early speculation for, andultimate rejection of, the idea of a Jurassic oil shale underlying the basin. Breman (Fugro-Robertson) thenreviewed the overlooked but potentially highly prospective Eastern Mediterranean, and showed severalseismic lines with major untested structures. The benefits of testing new fairways in established provinceswas clearly demonstrated by Shann et al. (BP), who reviewed the new Raven field discovery billed as a “PlayFairway Opener” in the western Nile Delta. They suggested that tens of TCF of as-yet undiscoveredreserves may reside in an early Miocene channel play located some kilometres below the prodigiousPliocene play.

Stampfli (University of Lausanne) demonstrated the importance of the application of rigorous NorthAfrica plate reconstructions to regional exploration. A debate clearly existed over the age of the EasternMediterranean, with Prof. Stampfli supporting the initiation of oceanic spreading in the Permian, in contrastto the Jurassic age favoured by the previous two speakers. To continue the theme of innovative explorationtechniques, Marwick (on behalf of the “Getech” team) outlined palaeo-climatic computer models with examplesfrom North/East Africa. Then Wornardt (Microstrat) demonstrated the potential of high-resolution sequencestratigraphy in the Gulf of Suez, which has led to the development of a field previously considereduncommercial.

In the final session of the day, Clark-Lowes and Hallett (Nubian Consulting) presented a statistical analysisof remaining oil reserves in Libya and showed some startling discrepancies with published data. Thismarried well with the next talk by Barsoum (E&D Consultants) which described two recent billion-barreldiscoveriess in the Sarir Sandstones in hangingwall traps in the vicinity of Gialo field. Sabaou (BHP) thendiscussed the porosity-enhancing and -destroying dolocretes in the TAG-I reservoir, Algeria. Finally, Baird(Woodside) outlined the increased understanding of clastic systems and accommodation space controlledby listric slumping offshore Mauritania, with examples from an extensive 3D dataset. The day ended witha screening of “The Petroleum Geology of Southern Libya”, a film directed and presented by SebastianLuning (University of Bremen).

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K. Gerdes (Shell) and C. Wurie (Govt. Sierra Leone) guided the first session’s proceedings on the secondday, which began with an introduction by Hutchinson et al. (RPS/ECL) which essentally constituted a Pan-African basin classification, laying the foundations for the presentations to follow. These began with a talkon Chad by Hill (Encana) who drew attention to new oil discoveries in the Bongor Basin. Moving east toMali, Scott (Mali Petroleum) showed that most of the country is currently held under licence, with companiespursuing largely Infracambrian plays in the Taoudenni Basin.

Moving to the West African rift margin, Henry et al. used long-offset PSDM data to give a regionalglimpse of the deep structures around the prolific deep Congo Fan, and derived a three-phase model forAtlantic rifting including a Late Jurassic phase which extended from the Sergipe Basin of Brazil to Gabon.This talk dovetailed with a presentation on regional salt structures by Davidson which included a well-illustrated tour of the “Aptian Salt Alps”, a subsurface “mountain range”100km wide with peaks risingsome 2km above the original depositional level. Geologists are familiar with the smooth curves of halo-kinetic flow, but halite at outcrop breaks “like concrete” and brittle faulting of a halite cap-rock is thereforepossible. Moving south, Robinson (Hunt Oil) introduced wildcat exploration in the Luderitz Basin of Nambia,describing deepwater prospects on the Outer Basin High. This was followed by Van der Spuy’s (PetroleumAgency SA) review of the adjacent Orange Basin, where there have been a few tantalising, technicallysuccessful hydrocarbon wells but as yet no major successes.

The final session was opened by Luc Saugy who reviewed the structural controls on the Niger Deltaand the characteristics of progradation and of trapping structures. This segued neatly with Radovitch (SilverGrass) who illustrated the latest long-offset PSDM seismic data over the deepwater province of the delta.With this new deep resolution, new play types were described tying to Akata Shale lowstand events and indeep partially eroded anticlines.

The auditorium was packed to hear Martin’s (Hess: Ceiba Equatorial Guinea Group) review of sourcerock research. He suggested that, although the Cenomanian-Turonian source rock is proven and maturein this area, the Late Albian may also be a key source rock, although this suggestion is based on source rockvolumetrics rather than a geochemical oil-to-source match. After the break, Jackson (RPS/ECL) presentedthe next set of deep images from long-offset seismic, this time tying the prolific Ceiba and Niger Deltaareas to the enigmatic Douala Basin, the location of a couple of interesting recent discoveries.

Nibbelink (Devon) gave an encouraging talk on how the Campanian success in Southern EquatorialGuinea could be repeaed in Ghana. The programme stayed with Ghana when Valasek et al. (Vanco) presentedvoluminous data on prospect generation in the Tano Basin. Both speakers pointed to a strategy wherebygood geoscience can be used to lower risk and create opportunities in a high-risk area, as an alternative tocompeting with the huge signature bonuses now demanded in established low-risk provinces.

The last paper (Hayman: IHS) gave a round-up of the gas development potential of the entire continentof Africa, mentioning yet-to-find value estimates. He noted that Africa has a significant contribution tomake to world reserves, especially with the recent emergence of a global gas business, although the timetaken to develop some individual fields has caused commercial concern.

The next of these Conferences will be held in Cape Town in September 2007, and is themed “FromOutcrop to Deepwater”. This welcome move to an African venue is taking place in order to encouragenew presenters and participants from African-domiciled organisations, as Sub-Saharan Africa is possibly theonly major producing region of the world lacking a dedicated regional geotechnical conference. Submissionsshould be sent to Duncan Macgregor (Duncan.macgregor@neftex.com).

Kevin Dale, Sasol (kevin.dale@uk.sasol.com)Stuart Munday, BG Group (stuart.munday@bg-group.com)