SEISMIC AVO STUDIES ASSIST IN THE MAPPING OF A PERMIAN GAS SAND AT KERNA FIELD, COOPER BASIN

1991 ◽  
Vol 31 (1) ◽  
pp. 244
Author(s):  
J. Pinchin ◽  
A.B. Mitchell
Keyword(s):  
South Australia ◽  
Flood Plain ◽  
Seismic Facies ◽  
Gas Field ◽  
Seismic Modelling ◽  
Coal Beds ◽  
South Central ◽  
Amplitude Versus Offset ◽  
Modelling Studies ◽  
Cooper Basin

Kerna is a gas field within the south-central part of the Cooper Basin, 12 km southwest of the Dullingari Field and adjacent to the border of South Australia and Queensland. The trap is a domal anticline containing gas structurally trapped within the Early Permian Patchawarra Formation. The overlying Permian Epsilon Formation, above intervening shale, also contains gas, which may be stratigraphically trapped or restricted by permeability barriers around the southern and western flanks of the field.Seismic reflection amplitudes can be used to map the extent of the Epsilon gas sand. Seismic modelling studies show that the gas sand displays an amplitude-versus-offset (AVO) effect which distinguishes the gas sand from a wet sand or from a coal reflection at the same stratigraphic level. The spatial distribution of the AVO anomalies, and of the overall seismic stack response, has been mapped across the field. The interpreted 'seismic facies' map shows a meander belt across a coal swamp dominated flood plain. The distribution of AVO anomalies within and around this meander belt shows the likely occurrence of gas-bearing sandstones.This study has implications for other areas of the Cooper Basin where adequate separation between coal beds and gas sands allows the AVO effect of the latter to be observed. These AVO effects can then be used as a direct indicator of gas in stratigraphic and structural traps.

A SEISMIC MODEL OF FAULTS IN THE COOPER BASIN

1984 ◽  
Vol 24 (1) ◽  
pp. 421
Author(s):  
R. J. Gray ◽  
D. C. Roberts
Keyword(s):  
Hanging Wall ◽  
South Australia ◽  
Shadow Zone ◽  
Seismic Line ◽  
Seismic Section ◽  
Seismic Modelling ◽  
Geological Cross Section ◽  
Major Fault ◽  
Seismic Lines ◽  
Cooper Basin

A synthetic seismic section was modelled to help in the interpretation of Cooper Basin seismic lines which cross major faults and exhibit shadow zones.A major fault bounding the northwest flank of the Packsaddle Structure in the Merrimelia-Innamincka Farmout Block in South Australia was selected for modelling. A geological cross-section postulated on the basis of wells on either side of the fault was fed into the seismic modelling package AIMS (Advanced Interpretive Modelling System — licensed by Geoquest International Inc.) to produce a synthetic seismic line. This synthetic line provided a realistic match with an actual seismic line across the fault. Pre-stack migration of the actual seismic data is suggested to provide additional evidence for the reliability of the model.The shadow zone in the synthetic section is caused by dipping events in the fault shadow zone created by compaction of the Toolachee and Patchawarra Formations along the hanging wall of the fault plane. The dipping events cause reflected energy to be detected outside the fault zone. The large component of compaction within the Permian section is largely ascribed to thick coal horizons. The possibility of petroleum traps in the hanging wall of the fault is inferred and drilling is recommended.

ECONOMICS OF GAS FIELD DEVELOPMENTS IN THE COOPER BASIN AFTER 1999

1997 ◽  
Vol 37 (1) ◽  
pp. 600
Author(s):  
R.C.M. McDonough
Keyword(s):  
Operating Cost ◽  
South Australia ◽  
Competitive Market ◽  
Field Size ◽  
Gas Field ◽  
Field Development ◽  
The Public ◽  
Cooper Basin

In February 1999 all Cooper Basin exploration acreage in South Australia, which has been under licence since 1954, will be relinquished and therefore become available to new explorers. To assist new explorers in evaluating exploration opportunities, Mines and Energy South Australia (MESA) has developed feasibility level costs for gas field developments which are independent of existing infrastructure owned by the Cooper Basin Joint Venturers. Alternatively, new producers may be able to negotiate access to existing facilities. MESA has developed estimated tolls based on pricing principles which imitate a competitive market. Tolls in this instance should lie between the operating cost of the facility as a minimum and the deprival value cost as a maximum.The study shows that if access to existing facilities is negotiated on a deprival value cost, fields with as little as 5 BCF (141 Mm3) recoverable raw gas are economic. However, if field development is totally independent of existing facilities, the minimum economic field size exceeds 35 BCF (987 Mm3) recoverable raw gas (assuming flaring of LPG is not permitted).MESA conducted this study based on data available in the public and commercial arenas. This demonstrates that it is possible for any company to develop their own data for development and negotiation purposes.

Emerging continuous gas plays in the Cooper Basin, South Australia

2012 ◽  
Vol 52 (2) ◽  
pp. 671
Author(s):  
Sandra Menpes ◽  
Tony Hill
Keyword(s):  
Shale Gas ◽  
South Australia ◽  
Flood Plain ◽  
Source Rocks ◽  
Early Permian ◽  
Gas Shale ◽  
Freshwater Lakes ◽  
Gas Desorption ◽  
Wet Gas ◽  
Cooper Basin

Recent off-structure drilling in the Nappamerri Trough has confirmed the presence of gas saturation through most of the Permian succession, including the Roseneath and Murteree shales. Basin-centred gas, shale gas and deep CSG plays in the Cooper Basin are now the focus of an escalating drilling and evaluation campaign. The Permian succession in the Nappamerri Trough is up to 1,000 m thick, comprising very thermally mature, gas-prone source rocks with interbedded sands—ideal for the creation of a basin-centred gas accumulation. Excluding the Murteree and Roseneath shales, the succession comprises up to 45% carbonaceous and silty shales and thin coals deposited in flood plain, lacustrine and coal swamp environments. The Early Permian Murteree and Roseneath shales are thick, generally flat lying, and laterally extensive, comprising siltstones and mudstones deposited in large and relatively deep freshwater lakes. Total organic carbon values average 3.9% in the Roseneath Shale and 2.4% in the Murteree Shale. The shales lie in the wet gas window (0.95–1.7% Ro) or dry gas window (>1.7% Ro) over much of the Cooper Basin. Thick Permian coals in the deepest parts of the Patchawarra Trough and over the Moomba high on the margin of the Nappamerri Trough are targets for deep CSG. Gas desorption analysis of a thick Patchawarra coal seam returned excellent total raw gas results averaging 21.2 scc/g (680 scf/ton) across 10 m. Scanning electron microscopy has shown that the coals contain significant microporosity.

CUTTAPIRRIE 1—AN OIL DISCOVERY IN THE EARLY JURASSIC OF THE EROMANGA BASIN

1981 ◽  
Vol 21 (1) ◽  
pp. 60
Author(s):  
T. M. Barr ◽  
Bridget C. Youngs
Keyword(s):  
South Australia ◽  
Early Jurassic ◽  
Oil Field ◽  
Gas Field ◽  
Oil Accumulation ◽  
Gas Accumulation ◽  
Eromanga Basin ◽  
Cooper Basin

Cuttapirrie 1 discovered a significant oil accumulation at a depth of 8 016 ft in the Early Jurassic Hutton Sandstone of the Eromanga Basin. In addition, it discovered a small gas accumulation at 9 386 ft in the underlying Permo-Triassic Cooper Basin of South Australia. The well was 210 km from the nearest Jurassic oil field and 30 km from the nearest gas field when it was drilled.

Re-evaluation of depositional models for the lower Permian Patchawarra Formation, Cooper Basin, South Australia: implications for petroleum exploration

2020 ◽  
Vol 60 (2) ◽  
pp. 794
Author(s):  
Carmine Wainman ◽  
Peter McCabe
Keyword(s):  
Cold Water ◽  
South Australia ◽  
Petroleum Exploration ◽  
Lower Permian ◽  
Time Intervals ◽  
Fine Grained ◽  
Coal Beds ◽  
Hyperpycnal Flows ◽  
Lenticular Bedding ◽  
Cooper Basin

The Late Carboniferous–Triassic Cooper Basin is Australia’s most prolific onshore petroleum province. The lower Permian Patchawarra Formation, which is up to 680 m thick and consists of up to 10% coal, is a major exploration target in the basin. Eighteen cores through the formation have been logged to re-evaluate the existing fluviolacustrine depositional model. The siliciclastics form fining- and coarsening-upward sequences that are 1–10 m thick. They are predominately fine-grained with abundant lenticular bedding, wavy bedding and thinly interlaminated siltstones and clays resembling varves. Granules and pebbles, interpreted as dropstones, are present throughout the formation. Coal beds are up to 60 m thick and rich in inertinite. Other than the coal beds, there is little evidence of the establishment of terrestrial conditions: roots are rare and there are no siliciclastic palaeosols. The siliciclastics are interpreted as the deposits of a large glaciolacustrine system, with the fining-upward successions deposited in subaqueous channels cut by hyperpycnal flows and the coarsening-upward successions deposited as overbank splays between those channels. Hyperpycnal flows may have resulted from sediment-laden cold water emanating from glacially-fed rivers, similar to those seen in many large glacial lakes in high latitudes and altitudes today. Much of the coal is interpreted as the accumulation of peats from floating mires that covered large parts of the glaciolacustrine system at certain time intervals. The high inertinite content of many coals is interpreted as the decay of organic matter within the floating mire. These new interpretations have the potential to enhance reservoir characterisation within the basin.

LITHOFACIES STUDY ON THE TOOLACHEE FORMATION, GIDGEALPA-MOOMBA-BIG LAKE AREA, COOPER BASIN, SOUTH AUSTRALIA

1973 ◽  
Vol 13 (1) ◽  
pp. 41
Author(s):  
Roger C. N. Thornton
Keyword(s):  
South Australia ◽  
Flood Plain ◽  
Depositional Environments ◽  
Core Material ◽  
Upper Permian ◽  
Limited Area ◽  
Lake Area ◽  
Opposite Trend ◽  
Flow Gradient ◽  
Cooper Basin

A lithofacies study on the Upper Permian Toolachee Formation has been conducted in the Gidgealpa-Moomba-Big Lake area to determine the suitability of the technique in the reconstruction of depositional environments and palaeogeographic trends throughout the Cooper Basin. The Toolachee Formation is one of the main gas producing intervals in the basin, especially in the area of study, which is approximately 2,000 square kilometres. Thirty-one wells drilled in this region indicate that the formation ranges in thickness from 35 metres to over 115 metres.The Toolachee Formation, taken as a whole, is too thick to show any significant features on a lithofacies map over the limited area of investigation. However, lithofacies maps of three approximately chronostratigraphic subdivisions of the same formation show both vertical and lateral trends. Vertically, the percentage of sandstone decreases from the lowermost subdivision to the uppermost subdivision; coal percentages show the opposite trend; and core material shows fining upwards sequences. Laterally, isopachous thin areas (depositional highs) in most cases correlated with an increase in shale or coal lithologies. Histograms of coal cycles show that the lower and middle parts have similar composite sequences of, from the base upwards, sandstone mixture of sandstone and shale-shalecoal.The depositional model proposed is an aggradational flood-plain which, prior to the commencement of deposition, had been eroded to a peneplain. Sediments were deposited from rivers of gradually declining flow gradient until marsh and lacustrine conditions prevailed for long periods of time. Deposition ceased at the sediplain stage.

Lithofacies analysis and sequence stratigraphy of the Roseneath-Epsilon-Murteree gas plays in the Cooper Basin, South Australia

2017 ◽  
Vol 57 (2) ◽  
pp. 749
Author(s):  
Fengtao Guo ◽  
Peter McCabe
Keyword(s):  
South Australia ◽  
Flood Plain ◽  
X Ray Diffraction ◽  
Sedimentary Evolution ◽  
Facies Associations ◽  
Three Stages ◽  
Mouth Bar ◽  
Mouth Bars ◽  
Stacking Patterns ◽  
Cooper Basin

The early–middle Permian Roseneath-Epsilon-Murteree (REM) strata of the Cooper Basin, South Australia, has conventional and unconventional gas plays. To better understand the sedimentary evolution of the strata, eight key cored wells for the REM in the South Australia were selected and more than 1400 m cores have been characterised to study the lithofacies, facies associations and associated stacking patterns. Twelve lithofacies are identified and further categorised into eight facies associations: (1) open lacustrine, (2) lacustrine shoreface, (3) flood plain/interdistributary bay/channel fill, (4) fluvial channel/distributary channel, (5) crevasse channel/splay/natural levee, (6) distributary mouth bar, (7) prodelta, and (8) mire/swamp. Cyclic stacking patterns are distinguished both in cores and well logs. X-ray diffraction analysis indicates the lower and middle parts of the Murteree Shale mainly consist of claystone and are characteristic of deep water sediments. The upper Murteree Shale has a larger percentage of silt and sand, which suggests an overall regressive process. The Epsilon Formation displays three stages of deposition: (1) a lower, thin, upward-coarsening package of beach and lacustrine shoreline deposits with a continued regression from the underlying Murteree Shale; (2) a coaly, middle unit deposited by distributary channels, crevasse splays, mires and delta mouth bars; and (3) an upper unit of cyclic coarsening-upward claystone, siltstone and sandstone, deposited in shoreline environments with fluvial modifications. The Roseneath Shale resulted from transgression after deposition of the upper Epsilon Formation with a relatively rapid rise of lake level marked by transgressive lags. A final coarsening-upward sequence of shoreline deposits indicates an ending phase of regression.

THE DELIA FIELD, COOPER BASIN, SOUTH AUSTRALIA

1973 ◽  
Vol 13 (1) ◽  
pp. 58
Author(s):  
Martin Pyecroft
Keyword(s):  
Joint Venture ◽  
South Australia ◽  
Upper Permian ◽  
Gas Field ◽  
Water Contact ◽  
Reservoir Characteristics ◽  
Cooper Basin

The Della gas field of the Cooper Basin, South Australia, was discovered by Pursuit Oil No Liability and joint venture associates in July 1970. The field covers an area of approximately 17,000 acres in a discrete culmination on the Nappacoongee-Murteree anticlinal trend.Production is from several fluviatile sandstone units within the Toolachee Formation of the Upper Permian Gidgealpa Group. The trap is essentially structural with a maximum closure of some 450 ft on the top of the Toolachee Formation above a probable gas-water contact at 6,460 ft subsea.Five of the seven wells drilled to date in the field have been completed as potential gas producers. Production occurs between 6,270 and 6,670 ft and the average total depth is 7,180 ft. Net pay thicknesses vary from 37 to 98 ft and good reservoir characteristics are typical of the producing sands in the field. Twenty-two days are normally required to drill and complete a productive well.

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