Licence History
Exploration of the waters of The Commonwealth of The Bahamas and
vicinity occurred essentially continuously from post World War II,
in the mid 1940s, until 1988 with exploratory well tests, occurring
approximately every twelve years. Compared to the modern day,
technologies used and survey techniques were primitive and well
locations were defined by bathymetry and the utilisation of jack-up
rigs rather optimising subsurface intersection. Now with Bahamas
Petroleum Company's tenure, modern technologies are being employed
in an attempt to finally fully realize the potential of these
waters.
Early exploratory activities in the mid to late Forties
comprising small, local gravity and magnetic surveys were performed
on contract for such companies as Gulf Oil, Standard Oil (Chevron),
Superior Oil and Shell. This early activity was designed to
highlight basin architecture rather than define specific structures
or targets but did result in the drilling of the first Bahamian
well (Andros Island #1), drilled onshore on Andros Island designed
to a target depth ("T.D.") of 14583 feet. The well was plugged and
abandoned with no significant hydrocarbon shows reported.
From 1948 to 1955, the region experienced only limited
exploratory activity, though Gulf, in 1948 and 1950, did attempt
the first experimental underwater seismic and gravity surveys.
Regionally, the Gulf 826-Y well was drilled west of Key West,
Florida, notable as the well flowed 18 barrels of 22-24API gravity
crude oil from an interval of anhydrite and carbonate (below
10,000ft) similar to those anticipated within the Bahamas Petroleum
Company southern licences.
In 1956, Bahamas California Co. (Chevron) and Bahamas
Exploration Co. (Gulf) performed a detailed seismic and engineering
survey of the Cay Sal Bank area culminating in the second
exploration well conducted in The Bahamas, the Cay Sal #1 (T.D.
18906 feet). The well was a joint test by the two companies drilled
in 1959 encountering "live oil shows" from 12682 feet to T.D., but
with no commercial quantities of hydrocarbons tested.
From 1959 to 1968, up to eight companies held the entire Bahamas
region under concession. Gulf and Chevron led the majority of the
exploratory activity by completing many experimental marine seismic
programs (including the use of dynamite as an energy source). The
lack of success in the acquisition of this primitive poor quality
marine seismic data in the bank regions did not encourage well
tests during this period.
In 1970, Gulf, Chevron and Mobil drilled a joint test, the Long
Island #1 well (T.D. 17,577 feet), though this well was plugged and
abandoned after having encountered live hydrocarbon shows at a
depth of approximately 15,900 feet. The rig was then moved to the
Great Isaac Bank where the Great Isaac #1 well was drilled by
Chevron to a total depth of 17,847 feet. This well did encounter
live hydrocarbon shows in the 16,900 feet to 17,700 feet depth
interval with an over pressured reservoir containing gassy water at
17,436 to 17,495 feet depth interval. However, no commercial
quantities of hydrocarbons were reported on tests.
From 1970 to 1983, industry exploratory activity involved new
digitally-based seismic, gravity and magnetic surveys. Academic
institutions and the Deep Sea Drilling Project were actively
involved in attempting to understand the nature of the carbonate
bank of The Bahamas through the acquisition of subsea and
subsurface samples as well as new seismic and potential field
data.
During the early 1980s a number of companies vied for
competitive licence positions in Bahamian waters such that by 1984
the companies strongly represented included Esso, Amoco, Tenneco,
Texaco, Arco, Breoco and Shell. In 1985, industry exploratory
activity included the completion of then state-of-the-art seismic
surveys, gravity and magnetic surveys, surface and subsea
geochemical surveys, and geotechnical site surveys. Tenneco Oil
Company was the leader in employing the greatest amount and variety
of exploratory surveys. Further, during this time the international
scientific Ocean Drilling Program drilled a series of tests to
gather shallow subsurface data.
By late 1986, Tenneco had decided to spud the Doubloon Saxon #1
well; the deepest test drilled in The Bahamas to date and located
within the current day Donaldson licence area. The well was
successfully drilled to 21,740 feet, T.D'ing in the early
Cretaceous above the regional Jurassic source rock intervals. The
well encountered a number of live oil shows over a thick interval
but did not report commercial quantities of hydrocarbons. Through
the Cretaceous, and especially below the Aptian level, sequences of
carbonates, fractured dolomites and anhydrites were encountered in
multiple potential, reservoir sequences. These units, with around
20 in number where log quality allowed evaluation,, represented
repeating units generally over 200' thick. The well was
drilled using a shallower water jack-up rig. Our reexamination of
the targeted structure has concluded that whilst a successful
drilling operation was conducted the well did not target a valid
trap.
Following this significant exploratory test, licence interests
remained with Tenneco and Shell (Shell having acquired Arco's
position). Subsequently additional post-drilling seismic surveys
were performed by Tenneco and Shell during 1986 and 1987 but all
licences were allowed to expire in 1988 so as to avoid incurring a
significant work obligation for 1989 of $250m, and due to the then
prevailing low oil prices (<$20/bbl).
Overall, the well results indicate the presence of a active
petroleum systems, based on the presence, especially in the pre-mid
Cretaceous sections, of oil shows of varying quality, abundant
reservoirs and seals, indications of source rocks, and hydrocarbon
saturations from log interpretation. Carbonates, the major
component rocks of this region, globally contain 60% of the world's
oil but are not often encountered by nor best understood by many of
todays major and independent oil companies. So now, into the modern
era of new 3D technologies, deeper water drilling equipment
becoming commonplace, escalating oil prices and sustained demand,
Bahamas Petroleum Company has the opportunity to complete the
exploration of this exciting potential hydrocarbon province.