The Government of Seychelles and the Seychelles Petroleum Company Ltd (SEPEC) are offering prospective open acreage to international oil companies who wish to explore for hydrocarbons in Seychelles.

Seychelles is a modern, politically stable multiparty democracy with good infrastructure to facilitate petroleum operation activities. SEPEC has available for review all well and geophysical data acquired since exploration began in 1977.

The economic and legal terms for exploration and production in Seychelles are laid down in a modern, concession- type Model Petroleum Agreement. The major provisions of the MPA provide for an internationally competitive return on investment.

SEPEC will be pleased to welcome your company personnel to Seychelles to examine the data and discuss petroleum exploration opportunities.

Petroleum Geology

The Seychelles Petroleum Frontier coincides with a microcontinental fragment of Gondwana that originally lay adjacent to western India, eastern Somalia and northeastern Madagascar. Thick, rift-generated Mesozoic sequences occur, yet only 4 exploration wells have been drilled, 3 of which were invalid by either failing to reach the objective or being sited off structure. Nevertheless, these wells have proven the presence of:

• 1. Oil-prone Source Rocks containing Type II kerogen in coaly deltaic shales of the Middle Jurassic and in marine shales of the Upper Jurassic

• 2. Mixed source rocks bearing Type II/III kerogen in deltaic marine shales of the Lower Cretaceous that are II correlative of oil-generating shales in Somalia

• 3. Gas-prone sources containing Type I kerogen in Upper Triassic fluvial shales and Paleocene marine shales, the latter being correlative of oil and gas generating source rocks of the Deep Continental Shelf trend of the Bombay High Oil Province offshore west India

• 4. Evidence of hydrocarbon generation and migration with well shows, such as 0.7 ml benzene in DST-1 of Reith Bank-1, 10,010 ppm of 99.8% n-C4 headspace gas coincident with as small fault in the same well and 20% petrol vapours at an immature level of volcanics in Owen Bank A-1

• 5. Clastic reservoirs with measured porosities up to 22% in the Early-Middle Jurassic

• 6. Sealing lithologies both locally in syn-rift, and regionally in post-rift sequences

An extensive seismic dataset, plus a variety of remote sensing data have been collected which bolster the well data by confirming the presence of:

• 1. A variety of trapping styles, dominated by tilted fault blocks, stratigraphic pinchouts and reefs

• 2. Multiple heating events, with the principal event post-dating trap formation

• 3. Hydrocarbon generation and migration with the presence of:
  

  - numerous DHIs on seismic, including gas chimneys, flat spots, bright spots, phase changes and chemosynthetic reefs

  - gas sniffer anomalies, involving ethane/iso-butane in the southeast and propane/normal butane/total hydrocarbon in the north and northeast

  - UV fluorescence anomalies, especially over the wells and in the southeast

  - 4 types of beach-stranded tar that correlate to the local source rock stratigraphy

Exploration History

The turn of the 1970s saw the first reflection seismic in the region when Mobil included the Seychelles Plateau and some of the adjacent banks on a regional survey from East Africa to Sri Lanka. These data, coupled with 470 km of reconnaissance seismic by Burmah Oil over the plateau in 1973, revealed a recognizably block faulted sequence overlain by a flat-lying sequence comparable to a rift-drift succession, with the sedimentary section reaching at least 6 km in thickness.

An influx of petroleum companies occurred in 1977 when three Petroleum Agreements were signed with Oxoco, Siebens and a Burmah Oil-led consortium. These companies acquired some 6,400 km of seismic data between 1977 and 1979, the interpretation of which revealed the presence of both structural and stratigraphic leads. However, only Amoco from the Burmah-led consortium was prepared to commit to a drilling phase and although the three subsequent wells were plugged and abandoned, all encountered hydrocarbon shows. Post-mortems have revealed that two of the wells were invalid tests, as Owen Bank A-1 failed to reach the objective due to rig limitations. The third well, Seagull-1, was drilled on a structural nose opening to the southeast. Reith Bank-1, had inadequate seal atop the primary objective.

Amoco remained optimistic and in 1982 commissioned a 27,900 km aeromagnetic survey, followed in 1983 by the acquisition of 7,100 km of seismic, gravity/magnetics and waterborne gas sniffer data around the Seychelles Plateau, as well as over the adjacent banks and the distant Farquhar/Providence area. Despite the presence of significant sedimentary packages and a number of leads and geochemical anomalies, however, Amoco relinquished their acreage in 1986 during a time of general industry upheaval.

That same year, the then Seychelles National Oil Company (SNOC) assumed responsibility for promoting the petroleum potential of Seychelles and the following year Enterprise Oil signed a Petroleum Agreement for the Southeastern Shelf plus Constant, Coetivy and Fortune Banks, with an option to later include Platte Bank. In 1987, Enterprise acquired 4,870 km of seismic and gravity/magnetics data and in 1990 opted to enter a drilling phase and take-up the option over Platte. In that same year, both Texaco and Ultramar also signed Petroleum Agreements.

The three licensees conducted a group-shoot acquisition programme in 1991, gathering 3,675 km of seismic and gravity/magnetics data. Enterprise also conducted an airborne UV fluorescence “Seepfinder” survey over its concession areas. In 1992 Texaco relinquished its acreage in favour of the newly opened Former Soviet Union, whilst in 1993 Lasmo, who had acquired the Ultramar acreage through takeover, relinquished its acreage as such frontier areas were not a company priority. Lasmo did, however, contribute towards a joint project with SNOC aimed at determining more fully the underlying tectonic framework of the region.

In 1995 Enterprise drilled the Constant Bank-1 well, but failed to reach the Cretaceous objective before abandoning the well. In mid 1996 Enterprise relinquished their acreage. Later that year Seychelles was included in a Canadian-sponsored regional study of the countries within and bordering the western Indian Ocean. Geochemical analysis of well cuttings during this study identified oil-prone Type II kerogen in the Middle Jurassic deltaic shales of the Seagull Shoals-1 well.

The Seychelles National Oil Company Limited embarked on a programme to widely distribute knowledge of the petroleum potential of the region through promotional material, seminars and technical publications. Also, apatite fission track analysis and thermal maturity modelling by Geotrack International and Dr Doug Waples indicated a multiple event heating history and good potential for source rock maturity.

In 2005, the Seychelles National Oil Company merged with the Seychelles Petroleum Company Limited (SEPEC) and currently exploration activities are being handled by the Exploration Department in SEPEC.

Contact Details
Seychelles Petroleum Co. Ltd
New Port
PO Box 222
Victoria
Mahe

Tel: +248 225182
Email: prjoseph@snoc.sc / info@seypec.com