Fortescue field, Gippsland basin: Flank potential realized

Conference · Sat Sep 01 04:00:00 EDT 1990 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:6129625

Hendrich, J H; Schwebel, D A; Palmer, I D ^[1]

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1. Esso Asustralia Ltd., Sydney, New South Wales (Australia)

Fortescue field was the last major oil field to be discovered in the offshore Gippsland basin, southeastern Australia. The discovery well, 1 West Halibut, was drilled in 1978 on the basis of a 1-km seismic grid as a follow up to the dry 1 Fortescue wildcat. Data from this well were interpreted to indicate that there was a high probability of a stratigraphic trap occurring on the western flank of the giant Halibut-Cobia structure. The 2, 3, and 4 Fortescue wells were drilled by early 1979 to determine the limits of the field, delineate the stratigraphy, and define the hydrocarbon contacts. Cobia A had the dual purpose of developing the Cobia field and the southern extent of the Fortescue reservoirs that were inaccessible to the Fortescue A plat-form. At the conclusion of development drilling in early 1986, eight Cobia A wells and 20 Fortescue A wells were capable of producing from Fortescue reservoirs. The Fortescue reservoirs are Eocene sandstones that were deposited in coastal plain, upper shoreface, and lower shoreface environments. Integration of well log correlations, stratigraphic interpretations, reservoir pressure data, and seismic data indicates that these Fortescue reservoirs are stratigraphically younger than, and are hydraulically separated from, the underlying Halibut-Cobia fields. Pressure data acquired during development drilling and while monitoring subsequent production performance have conclusively demonstrated that there are at least three separate hydraulic systems active within the Fortescue field. Fortescue field dimensions are approximately 11 km x 4 km with a maximum relief of 100 m above the original oil-water contact. Reserves are estimated at 280,000 STB, based on original oil in place estimates of 415,000 STB and recovery factors in the 65-70% range. Production rate peaked in 1984 at 100 K BOPD from the combined development facilities and was sustained until late 1986. More than two-thirds of the reserves have been produced to date.

• OSTI ID: 6129625
• Report Number(s): CONF-9010204--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Journal Volume: 74:9
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
58 GEOSCIENCES
580000 -- Geosciences
AUSTRALASIA
AUSTRALIA
CENOZOIC ERA
CORRELATIONS
DEPOSITION
DRILLING
ENERGY SOURCE DEVELOPMENT
EXPLORATION
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
GEOLOGIC TRAPS
GEOLOGY
GEOPHYSICAL SURVEYS
MINERAL RESOURCES
OIL FIELDS
PETROLEUM DEPOSITS
PRODUCTION
RESERVES
RESERVOIR PRESSURE
RESERVOIR ROCK
RESOURCES
ROCKS
SANDSTONES
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
SEISMIC SURVEYS
STRATIGRAPHY
SURVEYS
TERTIARY PERIOD
WELL DRILLING
WELL LOGGING