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This report is updated periodically to provide information on
the geology and the hydrocarbon discoveries within the Newfoundland and Labrador
offshore area. Information presented here is based on seismic and drilling data
that has been submitted to Government by the industry and has passed its period
of statutory confidentiality. The cross-sections and maps shown are in the form
of generalized schematics which have been designated to illustrate basic trap
type and field geometry.
The petroleum rights for twenty of the twenty-two hydrocarbon discoveries
included here are held by various companies via the Significant Discovery
Licence (SDL). Inclusion in this report in no way implies that a hydrocarbon
discovery will meet the criteria required to be declared a Significant Discovery
under the Canada-Newfoundland Atlantic Accord Implementation Act1. The North
Leif and Adolphus discoveries, which are described in this report, are not held
under SDL.
The "discovered recoverable resources" reported here were obtained from the
Canada-Newfoundland Offshore Petroleum Board (C-NOPB)2 1990-91 Annual Report
and are expressed at the 50 per cent probability of occurrence.
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| Abbreviations Used
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DST
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Drill-Stem Test
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MMCF
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Million Cubic Feet
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AOF
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Absolute Open Flow
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BCF
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Billion Cubic Feet
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TSTM
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Too Small To Measure
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TCF
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Trillion Cubic Feet
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Bbls/day
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Barrels Per Day
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NGL
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Natural Gas Liquid
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MMBbls
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Millions Barrels
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N/A
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Not Available
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Drill-Stem Test Symbols
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Oil Zone
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Gas Zone
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Oil & Gas Zone
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The offshore area of Newfoundland and Labrador encompasses
approximately 1.6 million square kilometres.
Geophysical surveys conducted by research institutes and government in the
1950's indicated that this region had all the prerequisites to become a major
petroleum province. As a result, the petroleum industry started exploration in
the region in the mid 1960's.
Exploration efforts during this period defined several basins (Figure 2) which
contain thick Mesozoic and Cenozoic sediments. These basins formed as North
America separated from Europe and Africa about 200 million years ago. This
separation later resulted in the opening of the present day Atlantic Ocean
through the processes of continental drift and sea floor spreading.
The Jeanne d'Are Basin, site of the Hibernia Field and most of the later
hydrocarbon discoveries, originated during this Mesozoic tectonic episode. It
contains up to 14 kilometres of sedimentary rock and is bounded by a series of
prominent faults. The basin plunges to the north and contains a variety of
sediments reflecting changing conditions as the basin evolved.
The oldest sediments in the basin are Triassic sandstones and shales. Continued
subsidence during the Jurassic resulted in extensive salt deposits, carbonates,
sandstones and shales. Late Jurassic sedimentation proved to be very important
in the basin's history, with an organically rich shale being deposited
throughout the basin. The organic material within this Kimmeridgian aged shale
is the major source of the Hydrocarbons that are being discovered in this area
today.
A significant change in sedimentation occurred during Late Jurassic and Early
Cretaceous in response to localized elevation of portions of the Grand Banks.
These uplifted areas were eroded and shed debris into the actively subsiding
basin. This debris formed the sandstone reservoirs which are the principal
hydrocarbon intervals within Hibernia and many of the other fields in this
basin. Further uplift resulted in a major re-structuring of the existing
sediments. Upper Cretaceous to Tertiary sedimentaion is characterized by shales
with sandstone and minor limestone.
The principal structural controls on trap formation are related
to the periods of relative subsidence of the basin and the associated faulting.
A second important structural influence, salt flowage, is evident today by the
presence of large salt domes within the central portion of the basin.
Hydrocarbons have been discovered in both carbonate and
sandstone reservoirs with ages varying from Paleozoic to Tertiary. To date, the
more significant discoveries are associated with down-to-basin faults or
cross-fault trends within the Jeanne d'Arc Basin
The Grand Banks basins have many geologic characteristics in common with the
North Sea. The distribution of the North Sea oil and gas fields is closely
linked with a major rift system as is the case in the Newfoundland region. The
hydrocarbon-bearing reservoirs and source rocks of the North Sea and the Grand
Banks discoveries are similar in age.
In contrast to the North Sea, Newfoundland's offshore is as yet relatively
unexplored. Of the 140 wells drilled to date, 117 were exploratory wells, of
which 20 resulted in significant hydrocarbon discoveries. The oil discoveries
have thus far been concentrated in and around the Jeanne d'Arc Basin. To date,
approximately 1.6 billion barrels of oil, 4.0 trillion cubic feet of natural gas
and 237 million barrels of natural gas liquids have been discovered in this area
alone. The total oil potential of the Jeanne d'Arc area is estimated to range
from 3.3 to 5.3 billion barrels at the 75 per cent and 25 per cent confidence
levels respectively.3
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(1) Canada-Newfoundland Atlantic Accord Implementation Act
(2) Canada-Newfoundland Offshore Petroleum Board
(3) C-NOPB 1989-90 Annual Report.
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