BASS AND GIPPSLAND BASINS: A COMPARISON

1984 ◽  
Vol 24 (1) ◽  
pp. 101
Author(s):  
J. K. Davidson ◽  
G. J. Blackburn ◽  
K. C. Morrison
Keyword(s):  
Vertical Migration ◽  
Upper Cretaceous ◽  
Oil And Gas ◽  
Normal Fault ◽  
Gas Condensate ◽  
Normal Faults ◽  
Lower Eocene ◽  
Light Oil ◽  
Recoverable Reserve ◽  
Gippsland Basin

After two decades of exploration, one wireline test of oil, one of light oil and several of gas and gas/condensate have been recovered from the Bass Basin while the adjacent Gippsland Basin has established an estimated ultimate recoverable reserve of the order of half a billion kilolitres of liquids and a quarter of a trillion cubic metres of gas. Geologically, the basins are similar.The alluvial and nearshore deposits at the top of the Latrobe Group in Gippsland are as porous and permeable as similar deposits at the top of the Eastern View Group in Bass.The Eastern View and Latrobe Formations are regionally sealed by the Upper Eocene Demons Bluff and Oligocene Lakes Entrance Formations respectively. The intra-Latrobe section in Gippsland has significant but regionally not very extensive sealing units, whereas the Lower Eocene to Paleocene sequence in Bass is increasingly shale prone with depth, sometimes over-pressured, and constitutes an extensive seal for a base of Tertiary play. This play comprises Paleocene shales sealing Upper Cretaceous clastics with hydrocarbons potentially sourced from both units.Maturation studies (Saxby, 1980) indicate that the Upper Cretaceous is the principal source for hydrocarbons in Gippsland with possible lesser contributions from the Lower Paleocene and Lower Cretaceous. Limited data indicate the same is true in Bass and that the Paleocene and parts of the Lower Eocene are mature sources for gas/condensate and light oil. Normal faults assist vertical migration in Gippsland. In Bass, relatively few normal faults penetrate the Paleocene and Lower Eocene shales to reach the top of the Eastern View, greatly restricting the chances of vertical migration over much of the basin. Vertical migration is more likely beyond the margins of the depocentre.Eroded anticlines at the top of the Latrobe form large traps for the bulk of Gippsland's hydrocarbons. Small anticlines, wrench-related features and intra-Latrobe closures are more difficult to find. The normal fault blocks in Bass at the top of the Eastern View are wrench-modified and have proven difficult to define.The recent recognition in Bass of the base of Tertiary play and the need for careful structural and seismic interpretations is expected to lead to discoveries of oil and gas.

GEOLOGIC EVOLUTION AND HYDROCARBON HABITAT GIPPSLAND BASIN

1972 ◽  
Vol 12 (1) ◽  
pp. 132 ◽  
Author(s):  
J. Barry Hocking
Keyword(s):  
Late Cretaceous ◽  
Upper Cretaceous ◽  
Meteoric Water ◽  
Oil And Gas ◽  
Basin Evolution ◽  
Fold Belt ◽  
Apparent Lack ◽  
Northern Flank ◽  
Southeastern Australia ◽  
Gippsland Basin

The Gippsland Basin of southeastern Australia is a post-orogenic, continental margin type of basin of Upper Cretaceous-Cainozoic age.Gippsland Basin evolution can be traced back to the establishment of the Strzelecki Basin, or ancestral Gippsland Basin, during the Jurassic. Gippsland Basin sedimentation commenced in the middle to late Cretaceous and is represented as a gross transgressive-regressive cycle consisting of the continental Latrobe Valley Group (Upper Cretaceous to Eocene or Miocene), the marine Seaspray Group (Oligocene to Pliocene or Recent), and finally the continental Sale Group (Pliocene to Recent).The hydrocarbons of the Gippsland Shelf petroleum province were generated within the Latrobe Valley Group and are trapped in porous fluvio-deltaic sandstones of the Latrobe. At Lakes Entrance, however, oil and gas are present in a marginal sandy facies of the Lakes Entrance Formation (Seaspray Group).The buried Strzelecki Basin has played a fundamental role in the development and distribution of the Cainozoic fold belt in the northern Gippsland Basin. The Gippsland Shelf hydrocarbon accumulations fall within this belt and are primarily structural traps. The apparent lack of structural accumulations onshore in Gippsland is largely due to a Plio-Pleistocene episode of cratonic uplift that was accompanied by basinward tilting of structures and meteoric water influx.The non-commercial Lakes Entrance field, located on the stable northern flank of the basin, is a stratigraphic trap and may serve as a guide for future exploration.

scholarly journals THE GEOLOGICAL STRUCTURE OF THE ALLOCHTHONOUS "ATHENS SCHISTS"

2004 ◽  
Vol 36 (4) ◽  
pp. 1550 ◽  
Author(s):  
Δ. I. Παπανικολάου ◽  
Σ. Γ. Λόζιος ◽  
K. Ι. Σούκης ◽  
Εμ. Ν. Σκούρτσος
Keyword(s):  
Internal Structure ◽  
Upper Cretaceous ◽  
Normal Fault ◽  
Accretionary Prism ◽  
Geological Structure ◽  
Detachment Fault ◽  
Metamorphic Rocks ◽  
Normal Faults ◽  
Low Grade

Based on lithological fades, deformation and metamorphic degree the alpine tectonostratigraphic complex known in the literature as "Athens Schists" is divided into two units: the non-metamorphosed overlying Athens Unit and the very low grade metamorphosed underlying Alepovouni Unit. Athens Unit crops out in several hills of the western and central part of the Athens Basin emerging through the post-alpine sediments. It comprises several lithologies that constitute two lithologie groups: the first one of neritic white massive-to thick-bedded carbonates that bear rudist fragments and Upper Cretaceous foraminifera. These limestones are olistholites within the second pelagic formation comprising marly limestones with Globotruncana sp., shales, sandstones, tuffs and ophiolithic blocks. Due to tectonic intercalating of these two lithological groups Athens Unit shows a complex internal structure. It represents an Upper Cretaceous mélange formed in an accretionary prism. Alepovouni Unit is observed at the eastern part of the Athens Basin along the foothills of Mt. Hymettos, wedged between Athens Unit and the metamorphic rocks of Mt. Hymettos. It comprises two lithological groups, in which remnants of Thassic fossils were reported. Alepovouni Unit is correlated to the allochthonous Lavhon Unit that tectonically overlies the autochthonous Attica Unit in SE Attica. At the eastern part of the Athens Basin, Alepovouni Unit is bounded by two west-dipping lowangle normal faults. Along these contacts the formations of both Athens and Alepovouni Units exhibit microstructures indicating top-to NW sense of shear. The contact between the Athens Unit and Alepovouni Unit in western Hymettos is probably a major extensional detachment separating the metamorphic units of Attica autochthon and Alepovouni at the footwall to the SE from the nonmetamorphic units of the Sub-Pelagonian and the Athens unit at the hangingwall to the NW. This major detachment fault accommodated the uplift of the metamorphic rocks and juxtaposed these two units. At the western part Athens Unit overlies tectonically the Paleozoic - Mesozoic formations of the Sub-Pelagonian unit. The contact is an east-dipping normal fault, antithetic to the major detachment of western Hymettos.

GIFFSLAND HYDROCARBONS - A PERSPECTIVE FROM THE BASIN EDGE

1984 ◽  
Vol 24 (1) ◽  
pp. 91 ◽  
Author(s):  
J. G. Stainforth
Keyword(s):  
Heat Flow ◽  
Upper Cretaceous ◽  
Oil And Gas ◽  
Source Rocks ◽  
Hydrocarbon Generation ◽  
Lower Tertiary ◽  
Late Tertiary ◽  
Carbonaceous Shales ◽  
Basin Edge ◽  
Gippsland Basin

Permit VIC/P19 lies palaeogeographically seaward of the main producing part of the Gippsland Basin. Deposition of the Latrobe Group commenced with volcanics and continental 'rift-stage' sediments during the Late Cretaceous. This phase was succeeded first by paludal sedimentation in the failed rift during the Campanian and Maastrichtian, and then by cyclic paralic sedimentation during the Paleocene and Eocene.Analysis of the hydrocarbons recovered during recent exploration of permit VIC/P19 shows that they were sourced from moderately mature coals and carbonaceous shales in the Campanian/-Maastrichtian paludal sequence.A maturation model that assumes elevated but decreasing heat flow, related to sea-floor spreading, produces an excellent fit to the observed maturity data and predicts a long history of hydrocarbon generation during the Tertiary. The maturity of the Upper Cretaceous source sequence depends more on the thickness of the overlying Lower Tertiary clastic Latrobe sediments than on the thickness of the Upper Tertiary carbonate wedge. The Late Tertiary phase of burial had relatively little effect on maturation because of its rapidity and the lower heat flow and higher thermal conductivities of the deeper sequence at the time. Overpressures in mature Upper Cretaceous source rocks, resulting from hydrocarbon generation, have driven pore fluids, including hydrocarbons, laterally up-dip into normally pressured reservoirs.The main oil province of the Gippsland Basin has a greater thickness of Lower Tertiary than has VIC/P19. As a result, source rocks are more mature there, and became wholly so by the end of deposition of the Latrobe Group. This facilitated charge of traps at the top of the Latrobe Group, which contain most of the oil and gas discovered to date in the Basin.

FLOUNDER — A COMPLEX INTRA-LATROBE OIL AND GAS FIELD

1987 ◽  
Vol 27 (1) ◽  
pp. 308
Author(s):  
M.W. Sloan
Keyword(s):  
Oil And Gas ◽  
Major Influence ◽  
Normal Faults ◽  
Gas Reservoir ◽  
Gas Field ◽  
North East ◽  
Wet Gas ◽  
Effective Seal ◽  
Gippsland Basin ◽  
Oil And Gas Reservoir

The Flounder Field is the deepest producing field in the Gippsland Basin. Since discovery in 1968 by Flounder 1, five delineation wells and 15 development wells have been drilled on the structure. The main T-1.1 oil and gas reservoir is trapped at the crest of a highly faulted anticline within the Latrobe Group. The Flounder structure has a complex deformational history with the Latrobe Group sequence undergoing two main phases of deformation. Late Cretaceous to Late Paleocene north-west trending normal faults are overprinted by a Late Eocene to mid Miocene north-east trending anticline. Generally within the Latrobe sequence in the Gippsland Basin, faulting destroys the integrity of the anticlinal features by breaking the lateral continuity of potential intra-formational seals. However, at the Flounder Field, the estuarine sands of the T-1.1 reservoir are overlain by a marine shale of adequate thickness to provide an effective seal across the faults.The T-1.1 oil and gas reservoir has excellent reservoir parameters. Separate gas caps are trapped in the multiple faulted crests of the structure and have had a major influence on the development of the field due to the resultant variation in gross oil column thickness.In addition, several small oil accumulations have been structurally and stratigraphically trapped in sediments filling the Tuna-Flounder Channel and the deeper Latrobe Group sequence.The Flounder Field commenced production in December 1984. Current estimated reserves for the T-1.1 reservoir are 155 billion cubic feet (BCF) (wet) gas and 115 million barrels (MMB) of oil, a dramatic increase over the 1978 pre-development estimated reserves of 86 BCF (wet) gas and 57 MMB oil.

Hanna of Wyoming—The Rockies’ Deepest Basin

2017 ◽  
Vol 54 (4) ◽  
pp. 265-293 ◽  
Author(s):  
Roger Matson ◽  
Jack Magathan
Keyword(s):  
Upper Cretaceous ◽  
Oil And Gas ◽  
Thrust Faults ◽  
Depositional History ◽  
Deep Sediment ◽  
Northern Margin ◽  
Lacustrine Shale ◽  
Hanna Basin ◽  
Fluvial Sandstone

The Hanna Basin is one of the world’s deeper intracratonic depressions. It contains exceptionally thick sequences of mature, hydrocarbon-rich Paleozoic through Eocene rocks and has the requisite structural and depositional history to be a significant petroleum province. The Tertiary Hanna and Ferris formations consist of up to 20,000 ft of organic-rich lacustrine shale, shaly mudstone, coal, and fluvial sandstone. The Upper Cretaceous Medicine Bow, Lewis, and Mesaverde formations consist of up to 10,000 ft of marine and nonmarine organic-rich shale enclosing multiple stacked beds of hydrocarbon-bearing sandstone. Significant shows of oil and gas in Upper Cretaceous and Paleocene rocks occur in the basin. Structural prospecting should be most fruitful around the edges where Laramide flank structures were created by out-of-the-basin thrust faults resulting from deformation of the basin’s unique 50-mile wide by 9-mile deep sediment package. Strata along the northern margin of the basin were compressed into conventional anticlinal folds by southward forces emanating from Emigrant Trail-Granite Mountains overthrusting. Oil and gas from Pennsylvanian to Upper Cretaceous aged rocks have been found in such structures near the Hanna Basin. Only seven wells have successfully probed the deeper part of the Hanna Basin (not including Anadarko’s #172 Durante lost hole, Sec. 17, T22N, R82W, lost in 2004, hopelessly stuck at 19,700 ft, unlogged and untested). Two of these wells tested gas at commercial rates from Upper Cretaceous rocks at depths of 10,000 to 12,000 ft. Sparse drilling along the Hanna Basin’s flanks has also revealed structures from 3,000 to 7,000 feet deep which yielded significant shows of oil and gas.

The 4 December 2015 Mw 7.1 Normal-Faulting Antarctic Plate Earthquake and Its Seismotectonic Implications

2020 ◽  
Vol 110 (3) ◽  
pp. 1090-1100
Author(s):  
Ronia Andrews ◽  
Kusala Rajendran ◽  
N. Purnachandra Rao
Keyword(s):  
Body Wave ◽  
Focal Depth ◽  
Normal Fault ◽  
Normal Faults ◽  
Oceanic Plate ◽  
Normal Faulting ◽  
Transform Faults ◽  
Wave Inversion ◽  
Spreading Ridges ◽  
Southeast Indian Ridge

ABSTRACT Oceanic plate seismicity is generally dominated by normal and strike-slip faulting associated with active spreading ridges and transform faults. Fossil structural fabrics inherited from spreading ridges also host earthquakes. The Indian Oceanic plate, considered quite active seismically, has hosted earthquakes both on its active and fossil fault systems. The 4 December 2015 Mw 7.1 normal-faulting earthquake, located ∼700  km south of the southeast Indian ridge in the southern Indian Ocean, is a rarity due to its location away from the ridge, lack of association with any mapped faults and its focal depth close to the 800°C isotherm. We present results of teleseismic body-wave inversion that suggest that the earthquake occurred on a north-northwest–south-southeast-striking normal fault at a depth of 34 km. The rupture propagated at 2.7  km/s with compact slip over an area of 48×48  km2 around the hypocenter. Our analysis of the background tectonics suggests that our chosen fault plane is in the same direction as the mapped normal faults on the eastern flanks of the Kerguelen plateau. We propose that these buried normal faults, possibly the relics of the ancient rifting might have been reactivated, leading to the 2015 midplate earthquake.

Sign in / Sign up

Export Citation Format

Share Document