Why is Everyone Excited About Deepwater Sao Tome and Principe EEZ: The 4 Key Reasons Why This has Been One of the Hottest Areas for Exploration in 2017

Abstract

Introduction The Săo Tomé and Príncipe Exclusive Economic Zone (STP-EEZ) has been the subject of significant industry attention in 2017 with major oil companies applying for exploration licenses over multiple open blocks. Seismic and gravity interpretation work has now been conducted to help explain the geological reasons for this interest. The STP-EEZ is bounded to the north by the Niger Delta with its prolific Tertiary deltaic petroleum systems, to the east by the Rio Muni and Douala basins which have witnessed exploration success in Cretaceous plays and to the south by the northernmost Aptian salt basin of Gabon with associated halokinetic plays and discoveries. The 4 key reasons why the STP-EEZ has been one of the hottest exploration areas of 2017: Syn-kinematic structures and source rocks: Historic geological interpretations have predicted that the STP-EEZ is underpinned by oceanic crust however, recent seismic data and gravity models suggest these areas contain a mélange of continental, transitional and oceanic crustal types with the potential for syn-kinematic structures and source rocks. Sub-Akata Shale plays in the distal parts of the Niger Delta: In the distal or outboard parts of the Niger Delta, an exciting new play concept that has captured the recent attentions of explorers lies within the sub-Akata sedimentary succession. Here, Cretaceous syn-kinematic sediment fills contain source rock material that may be mature for oil with hydrocarbons trapping beneath the Akata Shale. Thick sedimentary successions fed by long-lived fluvial systems: The waters of STP-EEZ have received the distal outputs of four major long-lived fluvial systems resulting in a thick succession of well-sorted, distal fluvial outflow sediments with associated good reservoir qualities. Basin Modelling studies suggest that syn-kinematic source rocks are mature: The results of recent basin modelling studies undertaken in STP-EEZ show that both the syn-kinematic sediments and the early post-kinematic sediments (Cenomanian-Turonian) are mature for oil are able to have charged the multiple overlying fluvial outflow sandstone reservoirs. Conclusions The recent excitement that the industry has experienced over STP-EEZ has its roots it the interpreted presence of syn-kinematic structures and source rocks and the provision of reservoir quality sands by long-lived fluvial outflows, which together provide the necessary elements of a working petroleum system.

AAPG Datapages/Search and Discovery Article #90332 © 2018 AAPG International Conference and Exhibition, Cape Town, South Africa, November 4-11, 2018