Geological controls on porosity and permeability in reservoir sands, Goodwyn field, Rankin Trend, northern Barrow-Dampier subbasin, northwest Shelf, Australia
- Curtin Univ., Perth, Western Australia (Australia)
- NCPGG/APCRC-Thebarton Campus, Adelaide, South Australia (Australia)
Goodwyn field is a major gas and condensate field with reserves of 4.1 tcf of gas and 254 million bbl of condensate and a 31-m oil rim in the southern part of the field. The field is a large tilted fault block open to the north and bounded by major faults to the south, west, and southeast. There are no significant internal faults within the field. The hydrocarbon-bearing reservoirs dip gently northwards at 5-6[degrees] and are truncated by the Main unconformity. Progressively younger units subcrop northward beneath the Main unconformity. Cretaceous deep-water marine sediments directly above the Main unconformity form the seal to the field. Core from the GE unit (main reservoir sand) defines two lithofacies: a medium to coarse-grained subarkosic unit (facies 1) and a fine to medium-grained subarkosic unit (facies 2). Both facies were laid down as channeled-braid plain to coarse-grained meander-belt sands. The overlying GD unit core defines a third sand lithofacies (facies 3): a fine to medium-grained sand characterized by abundant siderite. Although modified by a diagenetic overprint of quartz over-growths and kaolin cements, reservoir quality in the GE reservoir sands was established at the time of the deposition. Porosity pathways within facies 1 and 2 have acted as preferential conduits for ongoing fluid flow. In contrast, the finer grained and especially more clay-rich marine-associated GD sands (facies 3) have had their permeability reduced by the precipitation of authigenic quartz, kaolin, and siderite cements. Within the GE reservoir, zones with highest porosity are not a reliable indicator of the best of many excellent permeability sands. The most porous reservoir sands in the GE unit are not necessarily the most permeable. The coarser grained sands have wireline-derived porosities in the range 19-23%, yet they are better reservoirs than fine to medium-grained sands with porosities up to 26%. This is due to the relatively larger pores in the facies 1 sands.
- OSTI ID:
- 7132871
- Report Number(s):
- CONF-9310237-; CODEN: AABUD2
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (United States), Vol. 77:9; Conference: American Association of Petroleum Geologists (AAPG) mid-continent section meeting, Amarillo, TX (United States), 10-12 Oct 1993; ISSN 0149-1423
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
02 PETROLEUM
GEOLOGIC STRUCTURES
SEDIMENTATION
RESERVOIR FLUIDS
FLUID FLOW
RESERVOIR ROCK
QUALITY CONTROL
SAND
PERMEABILITY
POROSITY
AUSTRALIA
GAS CONDENSATE FIELDS
GEOLOGIC FAULTS
GEOLOGY
HYDROCARBONS
NATURAL GAS FIELDS
PETROLEUM DEPOSITS
AUSTRALASIA
CONTROL
DEVELOPED COUNTRIES
FLUIDS
GEOLOGIC DEPOSITS
GEOLOGIC FRACTURES
MINERAL RESOURCES
NATURAL GAS DEPOSITS
ORGANIC COMPOUNDS
RESOURCES
030200* - Natural Gas- Reserves
Geology
& Exploration
020200 - Petroleum- Reserves
Geology
& Exploration