GEOLOGY OF THE DELLA FIELD, A PERSPECTIVE ON THE HISTORY OF THE COOPER BASIN

1984 ◽  
Vol 24 (1) ◽  
pp. 266
Author(s):  
D. I. Gravestock ◽  
J. G. G. Morton
Keyword(s):  
South Australia ◽  
Early Permian ◽  
Channel Migration ◽  
Fault Activity ◽  
Facies Associations ◽  
History Of ◽  
Petrophysical Logs ◽  
Fluvial Sandstone ◽  
Active Channel ◽  
Cooper Basin

The Della Field produces dry gas from stacked fluvial sandstone reservoirs in the Early Permian Patchawarra Formation and Late Permian Toolachee Formation. Localised but severe fault activity and erosion in the late Early Permian have resulted in structural and stratigraphic complexities, particularly on the western flank of the field.A detailed study of lithofacies associations from cores has enabled constraints on the resolution of petrophysical logs to be appreciated. Within these constraints major facies associations are mappable across the field. Active channel migration in the Patchawarra Formation resulted in erosion and hence incomplete preservation of the fluvial sequence, which hinders mapping across the field. In contrast, the successive fluvial cycles of the Toolachee Formation are more completely preserved, enabling intrafield and some interfield correlation and mapping. The contrast is due to changing responses of the fluvial regime to prevailing tectonic conditions.A preliminary fluvial facies model, proposed after the first six Della wells, was upgraded during development drilling, with the result that productive reservoirs were successfully predicted. Integration of all available data provides one perspective on the evolution of the Cooper Basin in South Australia.

THE TIRRAWARRA SANDSTONE AND MERRIMELIA FORMATION OF THE SOUTHERN COOPER BASIN, SOUTH AUSTRALIA — THE SEDIMENTATION AND EVOLUTION OF A GLACIOFLUVIAL SYSTEM

1984 ◽  
Vol 24 (1) ◽  
pp. 377 ◽  
Author(s):  
B. P. J. Williams ◽  
E. K. Wild
Keyword(s):  
South Australia ◽  
Hydrocarbon Potential ◽  
Spatial Evolution ◽  
Fluvial Deposits ◽  
Temporal And Spatial Evolution ◽  
Depositional System ◽  
Facies Associations ◽  
Temporal And Spatial ◽  
The Relationship ◽  
Cooper Basin

An extensive sedimentological study of cores from the Permian Gidgealpa Group of the southern Cooper Basin has produced a new understanding of the relationship between the Tirrawarra Sandstone and the Merrimelia Formation. These two sequences were previously considered to be everywhere separated by a regional unconformity. This study has shown that the facies states, transitions and associations of both formations interdigitate so that typical 'Tirrawarra- type' fluvial deposits are present within glacigenic 'Merrimelia-type' sediments.The Merrimelia Formation was examined regionally in 29 cored wells. Typical facies occurring within the Formation include glaciofluvial outwash, extensive developments of subaerial and subaqueous diamictites, glaciolacustrine ripple-laminated sandstones and siltstones, and thick, monotonous mudrock sequences with clay-dominant rhythmite horizons.The Tirrawarra Sandstone was also examined regionally in 32 cored wells. Four major facies associations were identified within the Sandstone and indicate the temporal and spatial evolution of a fluvioglacial to predominantly fluvial depositional system. Locally the interrelationship between the Tirrawarra Sandstone and the Merrimelia Formation is clearly evident where basal outwash fan deposits of the Tirrawarra Sandstone are interbedded with typical Merrimelia lithotypes. The dominant, low-sinuosity fluvial channel sand facies of the Tirrawarra Sandstone is also an integral part of typical Merrimelia sediment patterns.The Merrimelia Formation and Tirrawarra Sandstone sediments are intimately related and illustrate the evolution of a predominantly glacigenic system into one in which fluvial processes dominate both in time and space. It is evident that no unconformity separates the two sequences and the inclusion of the Merrimelia Formation within the Gidgealpa Group is proposed.A distinct sedlmentological and stratigraphic identity has been assumed in evaluations of the hydrocarbon potential of the Tirrawarra Sandstone. The Merrimelia Formation has been considered generally non-prospective. This study indicates that potential exists for additional reservoirs of 'Tirrawarra type' to be locally developed within the Merrimelia Formation.

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.

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.

Mission Tracks in the Bush

2019 ◽  
Vol 3 (1-2) ◽  
pp. 103-124
Author(s):  
Gemma Tulud Cruz
Keyword(s):  
Nineteenth Century ◽  
Western Australia ◽  
South Australia ◽  
Nation Building ◽  
Cultural Encounters ◽  
History Of

Christian missionaries played an important role in the Australian nation building that started in the nineteenth century. This essay explores the multifaceted and complex cultural encounters in the context of two aboriginal missions in Australia in the nineteenth century. More specifically, the essay explores the New Norcia mission in Western Australia in 1846-1900 and the Lutheran mission in South Australia in 1838-1853. The essay begins with an overview of the history of the two missions followed by a discussion of the key faces of the cultural encounters that occurred in the course of the missions. This is followed by theological reflections on the encounters in dialogue with contemporary theology, particularly the works of Robert Schreiter.

The Status of the School Shark Fishery in South-Eastern Australian Waters

1959 ◽  
Vol 10 (2) ◽  
pp. 150 ◽  
Author(s):  
AM Olsen
Keyword(s):  
Maximum Yield ◽  
Reproductive Potential ◽  
South Australia ◽  
Slow Growth Rate ◽  
South Eastern ◽  
Pregnant Females ◽  
The Status ◽  
History Of ◽  
Annual Total ◽  
The Mean

The maximum yield of the school shark fishery in south-eastern Australian waters was 4.09 million lb in 1949. The catch has fluctuated since then about a declining trend to 3.18 million lb in 1956. In 1944, 7.3 hooks were required to catch a shark of mean weight 14.7 lb. In 1956 the number of hooks required was almost doubled: 13.6 hooks were needed to catch sharks of mean weight 13.7 lb; the catch per hook dropped from 2.01 to 0.99 lb. Whereas the catch per boat-month remained relatively stable at 4765 lb for 1944 and 4643 for 1956, the number of hooks used per boat-month increased from 2366 to 4668 hooks in 12 years. Throughout this period the mean weight of sharks in eastern Bass Strait remained fairly steady (11-13 lb) whereas there was a drop of 3 lb from a mean weight of 17-20 lb in the predominantly mature portion of the stock in western Bass Strait. Fishermen in South Australia have reported a comparable drop in the mean weight of sharks in their catches. During the period 1941-46 there was unrestricted inshore fishing of juveniles and pregnant females with a consequent severe drop in the inshore population. The subsequent decline in the annual total catch is believed to be due not only to a too intensive offshore fishery but also to the resultant reduced recruitment and depressed reproductive potential caused by the earlier destruction of juveniles and pregnant females. In the data presented in this paper there is evidence that the school shark fishery, which is operating on a single stock of sharks with a slow growth rate, a late sexual maturity, and a low fecundity, shows trends which are suggestive of depletion. Because similar trends in the soupfin shark fishery of California and in the dogfish fishery of British Columbia were followed by depletion, it has been inferred that regulations to protect the vulnerable phases of the life history of the school shark of Australia may be required. Measures for conservation are discussed.

Natural history of a plant trait: branch-system abscission in Paleozoic conifers and its environmental, autecological, and ecosystem implications in a fire-prone world

Paleobiology ◽  
10.1666/12030 ◽  
2013 ◽  
Vol 39 (2) ◽  
pp. 235-252 ◽  
Author(s):  
Cindy V. Looy
Keyword(s):  
Fire Regime ◽  
Climatic Conditions ◽  
Early Permian ◽  
North Central ◽  
Seasonally Dry ◽  
Plant Trait ◽  
Branch System ◽  
Central Texas ◽  
History Of ◽  
Biotic Disturbance

Within conifers, active abscission of complete penultimate branch systems is not common and has been described mainly from juveniles. Here I present evidence for the abscission of penultimate branch systems within early so-called walchian conifers—trees with a plagiotropic branching pattern. The specimens studied originate from a middle Early Permian gymnosperm-dominated flora within the middle Clear Fork Group of north-central Texas. Complete branch systems of three walchian conifer morphotypes are preserved; all have pronounced swellings and smooth separation faces at their bases. The source plants grew in a streamside habitat under seasonally dry climatic conditions. The evolution of active branch abscission appears to correspond to an increase in the size of conifers, and this combination potentially contributed to the restructuring of conifer-rich late Paleozoic landscapes. Moreover, trees shedding branch systems and producing abundant litter have the potential to affect the fire regime, which is a factor of evolutionary importance because wildfires must have been a source of frequent biotic disturbance throughout the hyperoxic Early Permian.

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