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Republic of Seychelles
Petroleum Potential & Exploration Opportunities Prepared by Seychelles National Oil Company Ltd for International Showcase SEG 2002 Patrick R Joseph Ag. Managing Director Patrick J Samson Senior Geologist
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Structure of the presentation
Introduction to Seychelles Exploration History Technical Issues Tectonic Evolution Source Rocks Reservoirs Seals Play Types Timing Indication of HC Data Availability Economic Issues There is oil to be found in Seychelles
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Introduction to Seychelles
Comprises 115 islands totaling 455 sq km scattered within an EEZ of 1.3 million sq km. The islands emerging from the main shallow water Seychelles Plateau, lying at the northwestern end of the Mascarene Ridge, are rugged, verdant granitic peaks that testify to their continental origin as part of the onetime supercontinent of Gondwana Lying between 1° and 12° south latitude within the western Indian Ocean, Madagascar and the East African states of Tanzania, Kenya and Somalia are its nearest neighbours.
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Introduction to Seychelles (cont.)
Population : 85,000 –Mixed Race living in harmony. Economy : based mainly on tourism & fisheries Climate : warm all year round (24 – 30 degree celcius) Infrastructure Versatile main port, being able to handle modern container ships Telecommunications (phone, fax, ) are satellite linked with direct dialing to most countries International airport visited regularly by international flights from Europe, South and East Africa, the Middle East and Southeast Asia Health Seychelles has a healthy environment, being free of malaria, yellow fever and other contagious diseases, and no vaccination certificates are required except from affected areas as recommended by W.H.O
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Exploration history The turn of the seventies witnessed the first reflection in the Seychelles region 1973: Burma Oil acquired 470km of reconnaissance seismic : Oxoco,Siebens and a Burma Oil-led consortium acquired some 6,400km of seismic data 1980/1981: Amoco drilled 3 wells on the western shelf 1982: Amoco commissioned a 27,900km aeromagnetic survey 1983: Amoco: Amoco acquired 7,100km of seismic, gravity/magnetics and Waterborne gas sniffer data. 1986: SNOC was formed 1987: Enterprise acquired 4,870 km seismic, And gravity/magnetic data. 1991: Texaco/Ultramar/Enterprise acquired 3,675km of seismic and gravity/magnetics 1991: Enterprise conducted an airborne UV Fluorescence seepfinder survey. 1995: Enterprise oil drilled the constant Bank Well. Canmar Explorer III during the Drilling of constant Bank-1
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Technical Issues : Tectonic Evolution
The complexity of the tectonic evolution of the Seychelles Plateau is due to the imposition of three phases of rift/drift tectonics that eventually cleaved the microcontinent from the centre of Gondwana. Early Cretaceous (~150 Ma0. After separation of East and West Gondwana Early Late Cretaceous (~95 Ma). During Seychelles/India split from Madagascar. Paleocene (~60 Ma). During The separation of India from Seychelles.
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Technical Issues : Source rocks Composite Stratigraphic Column
showing source rock horizons Hydrogen Index vs Oxygen Index for the lower to early middle Jurassic source rock. Note: Oil-prone Type II kerogen occurs in liptinitic coals (TCO = 63.4%) within early Middle Jurassic deltaic shales. H/C vs O/C Diagram for the Middle Jurassic to Lower Cretaceous source rock Beach standings of tar are a regular occurrence in Seychelles. The tars collected are correlable to the local stratigraphy.
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Technical Issues : Reservoirs & Seals
Where penetrated on the Western Shelf, fluvial and deltaic sandstones of rift origin had measured porosities up to 22% with flow rates of up to 1200 BWPD indicative of reasonable permeabilities. Early drift carbonates had porosities up to 18%. Similar or better porosities are expected in the younger rift clastics. Seals are present both regionally, as marine shales of drift origin, and locally, as shale interbeds within fluvial and deltaic sequences
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Technical Issues : Play Types Tilted Fault Blocks
Clastic continental and mixed clastic/carbonate marginal marine sequences of Triassic to Middle Jurassic and Late Cretaceous rift origin provide reservoirs and source rocks. These, and the capping and sealing fine-grained marine clastics, that also have source potential, have been block faulted during subsequent rift tectonism.
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Stratigraphic Pinchout
Technical Issues : Play Types Stratigraphic Pinchout Regressive marginal marine clastic sequences developed within a Late Cretaceous pull-apart rift basin provide reservoirs and source rocks. The landward pinchout is sealed between the underlying granitic basement and over-stepping fine grained clastics of transgressive marine origin.
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Technical Issues : Reefs Play Types
Barrier and fringing reefs developed on passive margins during Late Cretaceous and Tertiary drifting. Earlier marine shales, and associated marine shales and micritic carbonates could, respectively, source and seal the vuggy carbonate reservoirs
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Carbonate Onlap/Compactional Drape
Technical Issues : Play Types Carbonate Onlap/Compactional Drape Tertiary shelf carbonate onlap upon, or compactional drape over, major basement horst blocks or possible local volcanic edifices. Vuggy carbonate reservoirs are possibly sourced and sealed, respectively, by earlier or associated marine shales or micritic carbonates
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Wrench Fault Anticlines
Technical Issues : Play Types Wrench Fault Anticlines Wrench fault tectonics of latest Cretaceous/early Tertiary age created potentially large anticlines within Late Cretaceous progradational marine clastic sequences, containing reservoir facies. Overlying fine grained calcareous ooze could act as seals
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Technical Issues : Maturation v/s Timing
Recent AFTA and basin modeling has revealed a complete heating history. The principal heating event that took source rocks to organic maturity was the Deccan volcanic event at the Cretaceous/Teriary boundary, but other significant heating events both pre-, and post-date this event. The majority of structures had thus formed prior to the generation and migration of hydrocarbons
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Technical Issues : HC Indicators
Although none of the exploration wells discovered accumulations of hydrocarbons, shows in each well on the Western Shelf, plus other hydrocarbon indicators, indicate that hydrocarbons have been, and/or still are being generated from mature source rocks.
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Data Availability 23,150 line km of seismic - gravity & magnetic
27,911 km aeromagnetic Well data from the 4 wells drilled Gas sniffer survey (7,101 km) UV Fluorescence seep survey Several reports relating to the geological History and petroleum potential of Seychelles Seismic coverage Map
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Economic Terms The Model Petroleum Agreement was designed specifically to create a favourable environment for investment in petroleum exploration by oil companies. Contract type: Modern Concession-type with no State participation. Rent: US$10 per sq. km per year and adjusted annually for inflation. Royalty: 5% on gross production, but the Minister can reduce the rate for marginal fields. Bonuses: No signature or discovery bonuses. Training: A fund for training Nationals to be established by negotiation. Valuation: International fair market valuation of crude oil. Petroleum Income Tax: % with: * immediate expensing of all exploration and development costs for tax purposes; * unlimited carry forward of losses; and * no field ring-fencing. Additional Profits Tax: * Computed on cash flows denominated in US dollars; * levied on field-by-field basis; * two tier APT triggered only after the investor has earned a reasonable return on all expenditure; * trigger points and rates agreed upon by negotiation.
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www.snoc.sc Welcome to Seychelles Thank You
For more information and to know how to contact us go to : Welcome to Seychelles
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