THE GWYDION DISCOVERY: A NEW PLAY FAIRWAY IN THE BROWSE BASIN

1997 ◽  
Vol 37 (1) ◽  
pp. 87 ◽  
Author(s):  
T. B. Spry ◽  
I. Ward
Keyword(s):  
Oil And Gas ◽  
High Amplitude ◽  
Source Rocks ◽  
Shelf Area ◽  
Sequence Stratigraphic ◽  
Eastern Margin ◽  
Migration Pathway ◽  
Island Group ◽  
Basement High ◽  
Gas Bearing

The Gwydion-1 oil and gas discovery well is located in exploration permit WA-239-P on the sparsely explored Yampi Shelf area of the Browse Basin. The Gwydion feature was first recognised as a series of stacked seismic amplitude anomalies, which were interpreted to represent hydrocarbon-bearing Barremian to Albian age shallow marine sandstones draped over a prominent basement high. Amplitude versus offset analysis and modelling supported this interpretation.Gwydion-1 was spudded on 4th June, 1995, and discovered three gas bearing zones and one oil and gas bearing zone. The lowermost zone is Barremian to Hauterivian in age and consists of 12.6 m of net gas-filled glauconitic sand overlying a 9.5 m net oil-filled quartz sand. The three overlying hydrocarbon zones consist of glauconitic reservoirs of Barremian to Albian age.The play fairway for Gwydion-style traps has been named as the Echuca/Swan-Bathurst Island Group/Shelfal Play Fairway. It comprises mature Swan Group and Echuca Shoals Formation source rocks, and Bathurst Island Group reservoirs and seals. The limits of the play fairway on the shelf are controlled by the existence of topographic relief in the underlying basement metasediments. Migration pathway analysis suggests that the eastern margin of the Browse Basin is favourably situated to receive charge from the mature source rocks within the basin.The dominant northwesterly dip of the strata on the Yampi Shelf limits the potential for structural traps. Accordingly, a thorough understanding of the sequence stratigraphic architecture of the succession is necessary in order to generate the stratigraphic play concepts which hold the bulk of the prospectivity in the area.Gwydion-1 was plugged and abandoned as an uneconomic oil and gas discovery. It was, however, significant as it validated a new play type and generated renewed interest in the eastern margin of the Browse Basin for the first time since the mid 1970s; an area previously thought to be too shallow, too far from mature source and lacking reliable seal.

scholarly journals SEPARATE QUANTITATIVE PREDICTION OF OIL AND GAS CONTENT PROSPECTS FOR DZHEBOL STAGE PALEOZOIC DEPOSITS OF TIMAN-PECHORA OIL AND GAS BASIN

2015 ◽  
pp. 9-15
Author(s):  
A. I. Diyakonov ◽  
L. V. Parmuzina ◽  
S. V. Kochetov ◽  
A. Yu. Malikova
Keyword(s):  
Oil And Gas ◽  
Sedimentary Basin ◽  
Scientific Basis ◽  
Source Rocks ◽  
Gas Content ◽  
Quantitative Prediction ◽  
Oil And Gas Resources ◽  
Gas Bearing

It is shown that the evolutionary-catagenetic model for calculating the initial potential hydrocarbon resources can serve as a scientific basis for the separate quantitative prediction of areas of oil-and-gas content. In this case retrospectively evaluated are the scales of generation and accumulation of hydrocarbons in the source rocks during catagenetic evolution of sedimentary basin. The authors propose a method, the results of evaluation of generation and accumulation scales and initial potential oil and gas resources for major oil-and-gas bearing complexes of Dzhebol stage.

scholarly journals Prediction of reservoir sand in Miocene deltaic deposits in Denmark based on high-resolution seismic data

2007 ◽  
Vol 13 ◽  
pp. 17-20 ◽  
Author(s):  
Erik S. Rasmussen ◽  
Thomas Vangkilde-Pedersen ◽  
Peter Scharling
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
Seismic Reflection ◽  
Oil And Gas ◽  
Lower Miocene ◽  
Sequence Stratigraphic ◽  
Deep Aquifers ◽  
Gas Bearing

Intense investigations of deep aquifers in Jylland, western Denmark, during the last seven years have resulted in de tailed mapping of Miocene sand-rich deposits laid down in fluvial channels, delta lobes, shoreface and spit complexes (Fig. 1; Rasmussen 2004). Detailed sedimentological and paly nol ogical studies of outcrops and cores, and interpretation of high-resolution seismic data, have resulted in a well-founded sequence-stratigraphic and lithostratigraphic scheme (Fig. 1) suitable for prediction of the distribution of sand. The Miocene succession onshore Denmark is divided into three sand-rich deltaic units: the Ribe and Bastrup sands and the Odderup Formation (Fig. 2). Prodeltaic clayey deposits of the Vejle Fjord and Arnum Formations interfinger with the sand-rich deposits. Most of the middle and upper Mio- cene in Denmark is composed of clayey sediments referred to the Hodde and Gram Formations (Fig. 2). This paper presents examples of seismic reflection patterns that have proved to correlate with sand-rich deposits from lower Miocene deltaic deposits and that could be applied in future exploration for aquifers and as analogues for oil- and gas-bearing sands in wave-dominated deltas.

New exploration opportunities in the offshore Houtman and Abrolhos sub-basins, northern Perth Basin, WA

2013 ◽  
Vol 53 (1) ◽  
pp. 97 ◽  
Author(s):  
Nadege Rollet ◽  
Chris Nicholson ◽  
Andrew Jones ◽  
Emmanuelle Grosjean ◽  
George Bernardel ◽  
...  
Keyword(s):  
Joint Venture ◽  
Oil And Gas ◽  
Strong Support ◽  
Lower Triassic ◽  
Source Rocks ◽  
Burial History ◽  
Sequence Stratigraphic ◽  
Petroleum Systems ◽  
Integrity Analysis ◽  
Geochemical Studies

The 2013 Acreage Release Areas W13-19 and W13-20 in the offshore northern Perth Basin, Western Australia, cover more than 19,000 km2 in parts of the Houtman, Abrolhos, Zeewyck and Gascoyne sub-basins. The Release Areas are located adjacent to WA-481-P, the only active offshore exploration permit in the Perth Basin, granted to joint venture partners Murphy Australia Oil Pty Ltd, Kufpec Australia Pty Ltd and Samsung Oil and Gas Australia Pty Ltd in August 2012. Geoscience Australia recently undertook a regional prospectivity study in the area as part of the Australian Government’s Offshore Energy Security Program, which provides fresh insights into basin evolution and hydrocarbon prospectivity. A sequence stratigraphic framework, based on new biostratigraphic sampling and interpretation, and an updated tectonostratigraphic model, using multiple 1D burial history models for Permian to Cenozoic sequences, have been developed. New geochemical studies of key offshore wells demonstrate that the oil-prone source interval of the Lopingian–Lower Triassic Hovea Member extends regionally offshore into the Abrolhos Sub-basin and potentially as far as the Houtman Sub-basin. This is supported by fluid inclusion data that provide evidence for palaeo-oil columns within Permian reservoirs in wells from the Abrolhos Sub-basin. Oil trapped in fluid inclusions in Houtman-1 can be linked to Jurassic source rocks, suggesting that multiple petroleum systems are effective in the Release Areas. The presence of active petroleum systems is also supported by the results of a recent marine survey. Potential seepage sites on the seafloor over reactivated faults correlate with hydroacoustic flares, pockmarks and dark colored viscous fluids that were observed over the areas. This may indicate an active modern-day petroleum system in the Houtman Sub-basin. Finally, a trap integrity analysis was undertaken to mitigate exploration risks associated with trap failure during Early Cretaceous breakup and provides a predictive approach to prospect assessment. These results provide strong support for the presence of active petroleum systems in the offshore northern Perth Basin and upgrade the prospectivity of the Release Areas.

STRATIGRAPHY OF THE SOUTHERN SAHUL PLATFORM

1998 ◽  
Vol 38 (1) ◽  
pp. 115 ◽  
Author(s):  
V.R. Labutis ◽  
A.D. Ruddock ◽  
A.P. C alcraft
Keyword(s):  
Middle Jurassic ◽  
Oil And Gas ◽  
Depositional Environments ◽  
Source Rocks ◽  
Depositional Sequences ◽  
Sequence Stratigraphic ◽  
Sag Basin ◽  
Breakup Unconformity ◽  
East West ◽  
Reservoir Facies

This study of the southern Sahul Platform area in the Zone of Cooperation is based on the identification of depositional sequences, their distribution and relationship to structuring events in order to predict the locations of favourable combinations of source, seal and reservoir facies with increased confidence. A sequence stratigraphic approach integrating well logs, palynology and seismic data was used to identify and map significant seismic horizons such as the Aptian and Tithonian unconformities.Early to Middle Jurassic sediments were deposited in a broad, northeast-southwest oriented sag basin with a northeastward sediment transport direction. Depositional environments range from non-marine to marginal marine in the Plover Formation to the shallow marine sediments of the Elang Formation. The Elang Formation, comprising two depositional sequences, represents the last of the sediments deposited before the Breakup Unconformity. These formations comprise the dominant reservoir facies, containing a number of oil and gas discoveries. Porosity degradation occurs in Jurassic reservoirs below 3,360 m.The Callovian Breakup Unconformity resulted in the initiation of the narrow, confined depocentres of the Sahul Syncline, Malita Graben and a series of east-west troughs. The Sahul Platform and Londonderry High comprise the flanks of these depocentres but were originally located within the depocentre of the Early to Middle Jurassic sag basin. The Flamingo Syncline is a younger feature developed in the Albian.Late Jurassic and Early Cretaceous sediments are confined mainly to the Sahul Syncline and Malita Graben and are absent or represented by thin, condensed sections on the flanking highs. The condensed sections on horst blocks are a result of sediment bypass rather than considerable erosion. Reservoir facies of Tithonian-Berriasian age are interpreted to occur within east-west troughs constituting another reservoir section apart from the Bathonian-Callovian sediments. Wells distant from the Sahul Syncline and Malita Graben, have encountered hydrocarbons, indicating that the area contains mature source rocks, capable of charging traps away from the immediate vicinity of the depocentres.

ORIGIN OF GILMORE GAS AND OIL, ADAVALE BASIN, CENTRAL QUEENSLAND

1998 ◽  
Vol 38 (1) ◽  
pp. 399 ◽  
Author(s):  
C.J. Boreham ◽  
R.A. de Boer
Keyword(s):  
Oil And Gas ◽  
Isotope Composition ◽  
Vitrinite Reflectance ◽  
Sedimentary Basins ◽  
Source Rocks ◽  
Gas Generation ◽  
Migration Pathway ◽  
Wet Gas ◽  
Modelling Studies ◽  
High Maturity

Dry gas in the Gilmore Field of the Adavale Basin has been sourced from both wet gas associated with oil generation, together with methane from a deep, overmature source. The latter gas input is further characterised by a high nitrogen content co-generated with isotopically heavy methane and carbon dioxide. The eastern margin of the Lissoy Sandstone principal reservoir unit contains the higher content of overmature dry gas supporting reservoir compiirtmenmlisalion and a more favourable migration pathway to this region. The combination of a molecular and multi-element isotopic approach is an effective tool for the recognition of an overmature, dry gas source. This deep source represents a play concept that previously has been undervalued and may be more widespread within Australian sedimentary basins.The maturity level of the wet gas and associated oil are identical, having reached an equivalent vitrinite reflectance of 1.4−1.6 per cent. Modelling studies support the concept of local Devonian source rocks for the wet gas and oil. Reservoir filling from late stage, high maturity oil and gas generation and expulsion, was a result of reactivation of petroleum generation from Devonian source rocks during the Early Cretaceous. The large input of dry gas from a deeper and highly overmature source is a more recent event. This gas can fractionally displace condensable C2+ liquids already in the reservoir possibly allowing tertiary migration into younger reservoirs, or adjacent structures.Oil recovered from Gilmore-2 has been sourced from Devonian marine organic matter, deposited under mildly evaporitic, restricted marine conditions. The most likely source rocks in the Adavale Basin are the basal marine shale of the Log Creek Formation, algal shales at the top of the Lissoy Sandstone, and the Cooladdi Dolomite. Source-sensitive biomarkers and carbon isotope composition of the Gilmore-2 oil have much in common with other Devonian-sourced oils from the Bonaparte and Canning basins. The chemical link between western and eastern Australian Devonian oils may suggest diachronous development of source rocks over a wide extent. This implies that the source element of the Devonian Petroleum Supersystem may be present in other sedimentary basins.

South-Central Barents Sea Composite Tectono-Sedimentary Element, offshore Norway and Russia

2021 ◽  
pp. M57-2017-42
Author(s):  
A. G. Doré ◽  
T. Dahlgren ◽  
M. J. Flowerdew ◽  
T. Forthun ◽  
J. O. Hansen ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Barents Sea ◽  
Source Rocks ◽  
Novaya Zemlya ◽  
South Central ◽  
Marine Source ◽  
Basement High ◽  
Shallow Marine Sediments ◽  
Clastic Reservoirs ◽  
Near Future

AbstractThe south-central Barents Sea today comprises a shallow continental shelf with water depths mainly in the 200-400m range, straddling the Norway-Russia marine boundary. Geologically it consists of a stable platform (the Bjarmeland Platform), dissected by rifts of probable Late Carboniferous age, with a significant and geologically persistent basement high (the Fedynsky High) in its south-eastern part. The rifts are the ENE-WSW trending Nordkapp Basin, the similarly-trending but less clearly demarcated Ottar Basin, and the NW-SE Tiddlybanken Basin. The varying rift trends appear to reflect the orogenic grain patchwork of the basement (Caledonide and Timanide), and these basins were infilled with a variable facies assemblage including substantial Carboniferous-Permian halites.Massive sedimentary influx of fluvio-deltaic to shallow marine sediments took place in the Triassic, from the E and SE (Urals, Novaya Zemlya and western Siberia) and south (Baltic Shield), resulting in doming and diapirism in the areas of thickest salt, particularly in the rifts. The succeeding Jurassic, Cretaceous and Cenozoic successions are generally thin, locally thickening in rim synclines and in the NE of the area towards the deep basins flanking Novaya Zemlya. Reactivation of the halokinetic structures took place in the early Cenozoic, probably associated with the development of the NE Atlantic-Arctic Ocean linkage.Marine source rocks of Triassic and Late Jurassic age are present in the area, along with Carboniferous and Permian source rocks of uncertain effectiveness. Petroleum has been found in Jurassic and Triassic clastic reservoirs, including recent shallow Jurassic oil and gas discoveries. Although none are currently in production, near-future oil development is likely in Wisting discovery, on the western margin of the area. New exploration, including drilling, is currently taking place in the east of the area as a result of recent Norwegian and Russian licensing.

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