Fieldwork in North Africa including the Taoudenni Basin in Mauritania, Algeria and Mali; the Anti-Atlas region of Morocco and the Cyrenaica, Kufra and Murzuk basins in Libya has added to the understanding of reservoir, source and seal relationships and confirmed the widespread presence of Precambrian potential reservoir facies.
Cross-sections through the northern margin of the North Africa basin presented by Lu¨ning et al. (2009) and Rahmani et al. (2009) show the same threefold structural evolution, with active growth faulting during the ‘Glacial’ equivalent extensional phase, followed by Pan-African foreland basin development, and then severe inversion, uplift, erosion and peneplanation during the final stages of the Pan-African Orogeny, before the deposition of theoverlying Palaeozoic succession.
Neoproterozoic–Early Cambrian petroleum systems are widely developed globally and our knowledge of them is improving rapidly. The above has added substantially to our understanding of Neoproterozoic–Early Cambrian reservoir, source and seal relationships. This has confirmed the widespreadpresence of stromatolitic carbonate units of potential reservoir facies and of black shales with potential source rock characteristics in many Neoproterozoicsuccessions across North Africa, the Middle East and the Indian Subcontinent. Work is now underway to establish a robust lithostratigraphic and chronostratigraphic framework for the Voltain Basin of Ghana. There is already a widespread and growing perception that these plays will forman important target for future exploration in the, not only on the Voltain Basin, but also Togo and Benin; a perception strongly reinforced by the contributions to this Special Publication.
Samuel Oben Djan,Lead Geoscientist at GNPC - Neoproterozoic plays and hydrocarbon control
NEOPROTEROZOIC PLAYS ANDHYDROCARBON CONTROLSamuel Obeng-DjanLead GeoscientistTHE EMERGING POTENTIAL OF THEINLAND VOLTAIAN BASIN OF GHANA
OUTLINE Global Hydrocarbon Source Distribution The Global Neo-Proterozoic (Infra-Cambrian)Hydrocarbon Prospectivity Implication to the Voltaian Basin Where next? History of Exploration in Voltaian Basin The Voltaian Basin: Emerging Potential in West Africa
THE GLOBAL NEO-PROTEROZOIC (INFRA-CAMBRIAN) HYDROCARBON PROSPECTIVITY
WHAT DO WE KNOW ABOUT GLOBALHYDROCARBON OCCURRENCE?Western Canada& Onshore US75,000 Reservoirs/PoolsWestern Canada& Onshore US75,000 Reservoirs/PoolsWestern Canada& Onshore US75,000 Reservoirs/PoolsGLOBAL DISTRIBUTION OF OIL & GAS POOLS – >120,000 fields Nadeau et al. (1995)
CIRCLE OF KNOWLEDGEFieldwork in NorthAfrica including theTaoudenni Basin inMauritania, Algeriaand Mali; the Anti-Atlas region ofMorocco and theCyrenaica, Kufra andMurzuk basins inLibya has added to theunderstanding ofreservoir, sourceand seal relationshipsand confirmed thewidespread presenceof Precambrianpotential reservoirfacies.
WHAT DO WE KNOW ABOUT PRECAMBRIANPETROLEUM SYSTEMS OF AFRICA ?1EXPLORER’S QUESTIONS1) ARE ALL THESE LOCATIONS THOROUGHLY EXPLORED2) ARE SIMILAR GEOLOGICAL LOCATIONS UNEXPLORED/UNKNOWN3) DO DIFFERENT GEOLOGICAL SCENARIOS EXIST THAT ARE UNTRIEDCRAIG et al, 2009
WHAT DO WE KNOW ABOUT PRECAMBRIANPETROLEUM SYSTEMS OF THE AFRICA ?2EXPLORER’S QUESTIONS1) ARE ALL THESE LOCATIONS THOROUGHLY EXPLORED2) ARE SIMILAR GEOLOGICAL LOCATIONS UNEXPLORED/UNKNOWN3) DO DIFFERENT GEOLOGICAL SCENARIOS EXIST THAT ARE UNTRIEDCRAIG et al, 2009
WHAT DO WE KNOW ABOUT PRECAMBRIANPETROLEUM SYSTEMS OF THE AFRICA ?3EXPLORER’S QUESTIONS1) ARE ALL THESE LOCATIONS THOROUGHLY EXPLORED2) ARE SIMILAR GEOLOGICAL LOCATIONS UNEXPLORED/UNKNOWN3) DO DIFFERENT GEOLOGICAL SCENARIOS EXIST THAT ARE UNTRIEDCRAIG et al, 2009
The Neoproterozoic–Early Cambrian period canbe broadly divided into three distinct phasesrelated to global tectonics and climate:1. Tonian–Early Cryogenian: c.1000–750 Ma;2. Mid-Cryogenian–Mid-Ediacaran: c. 750–600 Ma;3. Late Ediacaran–Early Cambrian: c. 600–500Ma.THE NEOPROTEROZOIC–EARLY CAMBRIANPERIOD
The Late Ordovician–Early Silurian petroleum system in North Africa – an analogue forthe Voltain Neoproterozoic reservoir–source rock relationships?
THE NEOPROTEROZOIC–EARLY CAMBRIAN PERIOD CON’T• Recent fieldwork in the Taoudenni Basin in Mauritania• The Anti-Atlas region of Morocco• The Al Kufrah Basin in Libya,• The Naguar–Ganganagar Basin of Rajasthan,• The Son Valley of central India• The Himalayan foothills of NW India by members ofthe Maghreb Petroleum Research Group
Where next?THE VOLTAIN BASIN• One of the four (4) sedimentaryBasins of Ghana• It is the largest sedimentary basin inGhana• An Inland basin of size 103,600 sqkm (covers about 40% of Ghana’sland mass)• Basin extends into Togo and BeninVOLTAIAN
MSSP Data interpretation• a major deep basin underliesthe centre of the surveyarea, with a second shallowersub-basin located to thenortheast• Thickness of the varioussections of the basin rangesfrom deepest (> 6000m); in thenorthern & southern half of thebasin.• Shallower zones of 500mdepth mapped in SW & fringesbasin.• Averagely, the whole basin hasover 1000m sediment
Voltaian Basin-Current Status• Evaluation & Award of contract for thedrilling of slim holes is underway• Analysis of the data will establish thepetroleum system and enhance theknowledge base• That will end Phase I ( expected to becompleted by the end of the year 2013)• Phase II will begin with Investorparticipation.