Thermal maturation model of late Proterozoic-Paleozoic Amadeus basin, central Australia
The thermal maturation of the Amadeus basin, central Australia, was modeled using a modified version of Lopatin's time-temperature index. Assuming a constant geothermal gradient of 1.65/sup 0/F/100 ft to be representative of the basin, the amount of surface erosion was found to be the most significant factor controlling distribution of thermal facies. Interval-transit times in shales and palinspastic reconstructions of sedimentary thicknesses were used to estimate amounts of surface erosion and missing section associated with unconformities. An estimated 25,000 ft (7620 m) of section has been removed along the northern margin of the basin, with approximately 8000 to 9000 ft (2438 to 2.743 m) absent in the vicinity of the major oil and gas fields. The amadeus basin is an excellent example of a generation/migration/accumulation system favorable for commercial reserves of petroleum. The formation and accentuation of large anticlinal traps in Cambro-Ordovician sandstones slightly predated deep burial and strong oil generation in the Lower Ordovician Horn Valley Siltstone (Early to Late Carboniferous). The late Proterozoic Bitter Springs Formation, another possible source, was generative in the late Proterozoic to Early Ordovician. Suitable traps were also extant at this time. The thermal history of the Amadeus also demonstrates that maturation essentially halts if burial temperatures are substantially decreased by erosional unloading. In this manner sediments may remain deeply buried for long periods without undergoing substantial thermal alteration. The Amadeus is a very mature basin, with 47% of the strata being overmature (prospective for gas only).
- Research Organization:
- Mobil Exploration and Producing Services, Inc., Dallas, TX
- OSTI ID:
- 6183674
- Report Number(s):
- CONF-8304200-
- Journal Information:
- Am. Assoc. Pet. Geol., Bull.; (United States), Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Vol. 67:3; ISSN AAPGB
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020200* -- Petroleum-- Reserves
Geology
& Exploration
03 NATURAL GAS
030200 -- Natural Gas-- Reserves
Geology
& Exploration
AUSTRALASIA
AUSTRALIA
ENERGY SOURCES
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GASES
GEOLOGIC MODELS
GEOLOGIC STRUCTURES
GEOLOGIC TRAPS
GEOLOGY
MATURATION
NATURAL GAS
PETROLEUM
PETROLEUM GEOLOGY
RESERVOIR ROCK
RESOURCE POTENTIAL
SEDIMENTARY BASINS
SOURCE ROCKS