ELEVATED MID-CRETACEOUS PALAEOTEMPERATURES IN THE WESTERN OTWAY BASIN: CONSEQUENCES FOR HYDROCARBON GENERATION MODELS

1997 ◽  
Vol 37 (1) ◽  
pp. 505 ◽  
Author(s):  
M.M. Mitchell
Keyword(s):  
Upper Cretaceous ◽  
Vitrinite Reflectance ◽  
Geothermal Gradient ◽  
Hydrocarbon Generation ◽  
Key Factors ◽  
Factors Affecting ◽  
Early Maturation ◽  
Maximum Temperatures ◽  
Hydrocarbon Preservation ◽  
Uplift And Erosion

The Otway Basin formed during the Mesozoic separation of Antarctica and Australia. A study of apatite fission track (FT) analysis and vitrinite reflectance (VR) data from borehole samples in the western Otway Basin was initiated to elucidate some of the thermal and structural complexities of this region.Interpretation of results suggest that some areas experienced regionally elevated palaeotemperatures, however, much of the region is at present-day maximum temperatures. Where cooling from maximum palaeotemperatures is observed, the timing may be grouped over three main intervals as follows; mid-Cretaceous, Late Cretaceous to Early Tertiary, and Tertiary. Cooling was facilitated by a decline in geothermal gradient, uplift and erosion, or both. Evidence for a decline in geothermal gradient from values >55°C/km in the mid- Cretaceous is recognised in several wells. Elevated mid- Cretaceous palaeogeothermal gradients (50−60°C/km) have been reported for the eastern Otway Basin, suggesting that these high temperatures were a regional phenomena. Cooling by uplift and erosion at this time was minimal throughout the western Otway Basin in contrast to the kilometre scale uplift and erosion reported for the eastern Otway Basin and adjacent basement inland of this section of the rift.The relative early maturation of the Otway Supergroup during mid-Cretaceous regionally elevated geothermal gradients, and subsequent basin restructuring, are key factors affecting hydrocarbon preservation in the western Otway Basin. Strategies for identification of prospective areas include identification of regions that have remained at moderate temperatures during the Early Cretaceous, and have not undergone burial under a thick Upper Cretaceous to Tertiary section.

FOCUSSING EXPLORATION IN THE OTWAY BASIN: UNDERSTANDING TIMING OF SOURCE ROCK MATURATION

1997 ◽  
Vol 37 (1) ◽  
pp. 178 ◽  
Author(s):  
I.R. Duddy
Keyword(s):  
Late Cretaceous ◽  
Vitrinite Reflectance ◽  
Integrated Approach ◽  
Geothermal Gradient ◽  
High Heat ◽  
Source Rocks ◽  
Hydrocarbon Generation ◽  
Top Down ◽  
Early Maturation ◽  
Hydrocarbon Preservation

Quantitative reconstruction of the thermal and structural histories at key locations in the Otway Basin using an integrated approach based on AFTA® and vitrinite reflectance data reveals a regional pattern of elevated geothermal gradient prior to mid-Cretaceous cooling. Paleogeothermal gradients declined from −50 to 70°C/ km at −95 Ma to present day levels in the range −30 to 40°C/km by around 80 Ma. As a result, significant hydrocarbon generation must have occurred from the thick Late Jurassic to Early Cretaceous Otway Group section during the rapid rift-burial phase that preceded major mid-Cretaceous cooling.Regional decline in geothermal gradient in the Late Cretaceous leads to a 'two-stage' generation history for Otway Group source rocks because subsequent hydrocarbon generation did not recommence until the early maturation effects were overcome by greater Late Cretaceous and Tertiary burial. Such early, high heat flow is regarded as a feature of rift basins, and this results in an inverted pattern of hydrocarbon generation from rift source rocks that is here referred to as 'top-down generation', and which has a key influence on hydrocarbon prospectivity.Analysis of key hydrocarbon discoveries in the basin leads to the conclusion that all significant accumulations can reasonably be inferred to be sourced from the Otway Group, due to 'top-down generation5 delayed until the mid-Tertiary to present-day burial phase. This situation clearly favours hydrocarbon preservation in traps of a range of ages and has the added advantage of limiting the time available for traps to be breached in subsequent structuring episodes.This understanding of the decoupled relationship between the burial and thermal histories provides a sharp focus for further exploration of Otway Group-sourced accumulations, by defining areas with suitable thicknesses of the Late Cretaceous and Tertiary depositional packages which maximise the amount of re-generation since the mid-Tertiary.

LATERAL AND VERTICAL RANK VARIATION: IMPLICATIONS FOR HYDROCARBON EXPLORATION

1978 ◽  
Vol 18 (1) ◽  
pp. 143 ◽  
Author(s):  
A.J Kantsler ◽  
G. C. Smith ◽  
A. C. Cook
Keyword(s):  
Vitrinite Reflectance ◽  
Sedimentary Basins ◽  
Hydrocarbon Exploration ◽  
Hydrocarbon Generation ◽  
Marked Rise ◽  
Canning Basin ◽  
Early Maturation ◽  
Late Tertiary ◽  
Uplift And Erosion ◽  
Gas Fields

Vitrinite reflectance measurements are used to determine the vertical and lateral patterns of rank variation within four Australian sedimentary basins. They are also used to estimate palaeotemperatures which, in conjunction with present well temperatures, allow an appraisal of the timing of coalification and of hydrocarbon generation and distribution.The Canning Basin has a pattern of significant pre-Jurassic coalification which was interrupted by widespread uplift and erosion in the Triassic. Mesozoic and Tertiary coalification is generally weak, resulting in a pattern of rank distribution unfavourable to oil occurrence but indicating some potential for gas. The Cooper Basin also has a depositional break in the Triassic, but the post-Triassic coalification is much more significant than in the Canning Basin. The major gas fields are in, or peripheral to, areas which underwent strong, early, telemagmatic coalification whereas the oil-prone Tirrawarra area is characterized by a marked rise in temperature in the late Tertiary. The deeper parts of the Bass Basin underwent early coalification and are in the zone of oil generation, while most of the remaining area is immature. Inshore areas of the Gippsland Basin are also characterized by early coalification. Areas which are further offshore are less affected by this phase of early maturation, but underwent rapid burial and a sharp rise in temperature in the late Tertiary.

scholarly journals Estimating amount and timing of Late Palaeozoic uplift and erosion in the Rønne Graben, Bornholm, Denmark

1995 ◽  
Vol 42 ◽  
pp. 23-33
Author(s):  
Solvejg Kolbye Jensen ◽  
Søren Bom Nielsen
Keyword(s):  
Vitrinite Reflectance ◽  
Geothermal Gradient ◽  
Maximum Temperature ◽  
Model Parameter ◽  
Basin Modelling ◽  
Late Palaeozoic ◽  
Upper Silurian ◽  
Uplift And Erosion ◽  
Parameter Values ◽  
Reflectance Profile

Late Palaeozoic uplift and erosion is evidenced by a discontinuous vitrinite reflectance profile of the Pernille-1 well situated in the Rønne Graben. Modelling vitrinite reflectance evolution by the methods of basin modelling, the unconformity is estimated to represent Late Carboniferous uplift and erosion of 3,300 m of Upper Silurian and Devonian sediments. Given a vitrinite reflectance value of 1.7% at the erosional surface, the maximum temperature obtained during deepest burial is 160-165°C, corresponding to a geothermal gradient of approximately 50°C/km. The sensitivity of the erosion estimate to the choice of model parameter values is quantified. For example, a +10% uncertainty in the geothermal gradient equals an uncertainty of +400 m in the erosion estimate.

scholarly journals Overpressures in the central Otway Basin: the result of rapid Pliocene–Recent sedimentation?

2011 ◽  
Vol 51 (1) ◽  
pp. 439 ◽  
Author(s):  
David Tassone ◽  
Simon Holford ◽  
Mark Tingay ◽  
Adrian Tuitt ◽  
Martyn Stoker ◽  
...  
Keyword(s):  
Late Miocene ◽  
Upper Cretaceous ◽  
Source Rocks ◽  
Hydrocarbon Generation ◽  
Key Factors ◽  
Submarine Channels ◽  
Early Pliocene ◽  
Pore Pressures ◽  
Clastic Sediments ◽  
Drilling Data

This paper reports the first evidence for significant overpressures in the Otway Basin, southern Australia, where most previous studies have assumed near-hydrostatic pore pressures. Overpressures are observed in the Upper Cretaceous Shipwreck supersequence in several wells in the Voluta Trough, such as Bridgewater Bay–1, Normanby–1 and Callister–1. One of these wells penetrated successions of Pliocene-Recent marine clastic sediments nearly 700 m thick that were deposited rapidly in submarine channels and that were probably carved during the late-Miocene to early-Pliocene. Wireline and drilling data suggest that overpressures present in Upper Cretaceous shales and sandstones in the Belfast Mudstone and Flaxman and Waarre formations developed either due to disequilibrium compaction—where there is no evidence of hydrocarbon generation and thick Pliocene stratigraphy is present—or due to fluid expansion where there is evidence of hydrocarbon generation and the Pliocene stratigraphy is thin to absent. The two key factors that may indicate abnormal pore pressures in Upper Cretaceous sediments in the central Otway Basin are the thickness of Pliocene stratigraphy and whether or not hydrocarbons are actively generating from source rocks.

SOURCE, MATURITY AND GAS COMPOSITION RELATIONSHIPS IN THE SOUTHERN COOPER BASIN

1980 ◽  
Vol 20 (1) ◽  
pp. 191
Author(s):  
D.A. Schwebel ◽  
S.B. Devine ◽  
M. Riley
Keyword(s):  
Vitrinite Reflectance ◽  
Sedimentary Basins ◽  
Geothermal Gradient ◽  
Temperature Gradients ◽  
Land Plants ◽  
Hydrocarbon Generation ◽  
Gas Composition ◽  
Wet Gas ◽  
Structural Zones ◽  
Cooper Basin

In the Permian sedimentary sequence of the Cooper Basin, land plants contributed the bulk of the organic matter to the sediments. Inertinite, vitrinite and exinite are common kerogen types present in the organic-rich shales. Coal thickness varies areally.The geothermal gradient, though varying (from area to area), is everywhere higher than normal for sedimentary basins. The whole of the Permian sequence is mature for hydrocarbon generation. The highest temperature gradients of up to 3.19°F/100’ are measured in the Nappamerrie Trough and are associated with areas of granitic basement. Vitrinite reflectance profiles confirm that the sediments are thermally mature.Trends of gas composition indicate three distinct regions with gases trapped in:the Patchawarra Trough tend to be high in CO2 and wet gas;the Nappamerri Trough tend to be high in CO2 and low in wet gas; andthe Tennapera Trough tend to be low in CO2 and moderately high in wet gas.These differences in gas composition are accounted for by differences in thermal history within structural zones.

TIMING CONSTRAINTS ON THE STRUCTURAL HISTORY OF THE WESTERN OTWAY BASIN AND IMPLICATIONS FOR HYDROCARBON PROSPECTIVITY AROUND THE MORUM HIGH, SOUTH AUSTRALIA

2003 ◽  
Vol 43 (1) ◽  
pp. 59 ◽  
Author(s):  
I.R. Duddy ◽  
B. Erout ◽  
P.F. Green ◽  
P.V. Crowhurst ◽  
P.J. Boult
Keyword(s):  
Late Cretaceous ◽  
Vitrinite Reflectance ◽  
South Australia ◽  
Source Rocks ◽  
Hydrocarbon Generation ◽  
Seismic Line ◽  
Late Paleocene ◽  
History Of ◽  
And Migration ◽  
Uplift And Erosion

Reconstructed thermal and structural histories derived from new AFTA Apatite Fission Track Analysis, vitrinite reflectance and (U-Th)/He apatite dating results from the Morum–1 well, Otway Basin, reveal that the Morum High is a mid-Tertiary inversion structure. Uplift and erosion commencing in the Late Paleocene to mid-Eocene (57–40 Ma) removed around 1,500 m of sedimentary section. The eroded section is attributed to the Paleocene- Eocene Wangerrip Group which is considered to have been deposited in a major depocentre in the vicinity of the present Morum High. This depocentre is interpreted to have been one of a number of transtensional basins developed at the margin of the Morum Sub-basin and adjacent to the Tartwaup Hinge Zone and Mussel Fault during the Early Tertiary. The Portland Trough in Victoria represents a similar depocentre in which over 1,500 m of Wangerrip Group section, mostly represented by deltaic sediments of the Early Eocene Dilwyn Formation, is still preserved.Quantification of the maximum paleotemperature profile in Morum–1 immediately prior to Late Paleocene to mid-Eocene inversion shows that the paleo-geothemal gradient at the time was between 21 and 31°C/km, similar to the present-day level of 29°C/km, demonstrating that there has been little change in basal heat flow since the Early Tertiary.Reconstruction of the thermal history at the Trumpet–1 location reveals no evidence for any periods of significant uplift and erosion, demonstrating the relative stability of this part of the Crayfish Platform since the Late Cretaceous.The thermal and burial histories at Morum–1 and Trumpet–1 have been used to calibrate a Temis2D hydrocarbon generation and migration model along seismic line 85-13, encompassing the Crayfish Platform, Morum High and Morum Sub-basin. The model shows the cessation of active hydrocarbon generation from Eumeralla Formation source rocks around the Morum High due to cooling at 45 Ma (within the range 57–40 Ma) resulting from uplift and erosion of a Wangerrip Group basin. There has been almost no hydrocarbon generation from the Eumeralla Formation beneath the Crayfish Platform.Migration of hydrocarbons generated from the Eumeralla Formation began in the Late Cretaceous in the Morum Sub-basin and is predicted to continue to the present day, with the potential for accumulations in suitably placed reservoirs within the Late Cretaceous package both within the Morum Sub-basin and at the southern margin of the Crayfish Platform.

EVALUATION OF FINANCIAL SECURITY OF THE REPUBLIC OF CRIMEA

2020 ◽  
pp. 56-67
Author(s):  
Elena Evgenevna Mashyanova ◽  
Elena Aleksandrovna Smirnova
Keyword(s):  
Financial Markets ◽  
Negative Impact ◽  
Gradual Increase ◽  
Financial System ◽  
Financial Security ◽  
Key Factors ◽  
Factors Affecting ◽  
External Threats ◽  
The Republic ◽  
Global Financial System

In modern conditions of development, financial security is an integral part of the overall security of the region and is formed on the basis of the functioning of the financial system. The complication of relationships between key segments of international financial markets, as well as the limited ability to accurately predict future trends in the development of the global financial system, lead to a gradual increase in the risks that accompany the activities of economic entities, and an increase in the number and scale of internal and external threats that have a negative impact on the financial security of the state. This formulation of the issue requires generalization of approaches to determining the financial security of the region in order to further formalize this issue and determine the key factors affecting it. The article considers the types of financial security, as well as certain areas of ensuring the financial security of the region and their priority. In work the assessment of the level of socio-economic development of the region with a view to ensuring financial security on the basis of which offers the main activities and priority areas of implementation of the investment policy that will ensure financial security of the Republic of Crimea.

scholarly journals Comparison of the sensitivity of Western blotting between PVDF and NC membranes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yufang Xiang ◽  
Yuanyuan Zheng ◽  
Shaobo Liu ◽  
Gang Liu ◽  
Zhi Li ◽  
...  
Keyword(s):  
Western Blotting ◽  
Polyvinylidene Fluoride ◽  
Staining Intensity ◽  
Detection Sensitivity ◽  
Key Factors ◽  
Post Translational Modifications ◽  
Factors Affecting ◽  
Molecular Weights ◽  
Direct Blue ◽  
The Relationship

AbstractWestern blotting (WB) is one of the most widely used techniques to identify proteins as well as post translational modifications of proteins. The selection of electroblotted membrane is one of the key factors affecting the detection sensitivity of the protein which is transferred from gel to membrane in WB. The most common used membranes are polyvinylidene fluoride (PVDF) and nitrocellulose (NC) membranes. Which membrane of these two is more suitable for WB has not been reported so far. Here, by incubating proteins which were transferred to PVDF or NC membranes with a series of antibodies and different types of lectins, we investigated the relationship between the binding ability of these two membranes to proteins or glycoproteins and the molecular weight of the target protein. The antibody re-probed ability of the two membranes was also explored. Moreover, we verified the above results by directly incubating proteins having different molecular weights onto PVDF or NC membranes. Bound proteins were stained with direct blue-71, and the staining intensity was quantitated by scanning and densitometry.

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