Marathon Oil Corporation has commissioned Envoi to assist in its search for a quality partner to participate in the drilling phase of its 100% owned and operated, 1,120 km2 Tchicuate (G13) Licence offshore southern Gabon. The acreage is on the highly prospective margin of the largely undrilled deeper water South Gabon Basin, and located immediately outboard of the proven producing pre-salt Etame oil fields and Dussafu discoveries in shallower water. Significantly, 2 of the recent pre-salt exploration wells (Diaman, Leopard) in the region have found significant amounts of hydrocarbons.
The area’s primary play consists of stacked lower Cretaceous pre-salt Gamba and Dentale sands, overlying source rocks including the highly organic Melania ‘hot shale’. This sequence was deposited in the Dentale Paleo-Trough during the early continental break up, rifting and separation of what is now Brazil and Africa. A variety of trap-types have been identified. Upside potential exists in the post-salt Cretaceous Madiela play, which is prolific in Congo and Angola.
Regional gravity data clearly indicates that the Tchicuate acreage sits immediately west of the Atlantic Hinge line on the flank of the Dentale Palaeo-Trough. Here, basin modelling suggests more of the source rock is in the oil window compared to the more mature, gas prone central part of the trough, as defined by the Diaman and Leopard discoveries. Furthermore, Tchicuate is interpreted to contain thicker delta front sediment sequences fed from the east and ponded over the hinge zone on the trough flanks. The new CGG multi-client BroadSeis PSDM 3D seismic data over the block, processed for Marathon on an accelerated basis, provides excellent imaging in the pre-salt section. Marathon’s interpretive work has identified multiple well-imaged prospects, with a combined resource potential exceeding 1 Bn bbls oil recoverable.
The PSC was awarded in August 2014 and is in the first exploration period, with an outstanding exploration well commitment prior to the end of 4 year period. Given moderate drilling depths of 2,000-3,500 meters below seabed mudline over the prospects and favourable rig rates the prospects can be tested very economically.
Fiscal terms were negotiated prior to the new 2014 O&G Hydrocarbon law terms, providing a very attractive return.
Marathon would like to find a partner willing to earn 40% or more equity in the Tchicuate Licence in return for a negotiated contribution to the planned well and past costs.