SUPPRESSED VITRINITE REFLECTANCE AND ITS EFFECT ON THERMAL HISTORY MODELLING IN THE BARROW AND DAMPIER SUB-BASINS.

1996 ◽  
Vol 36 (1) ◽  
pp. 428 ◽  
Author(s):  
A. R. Kaiko ◽  
P. R. Tingate

The Barrow and Dampier Sub-basins form an important offshore petroleum province containing major oil discoveries associated with Triassic to Cretaceous reservoirs and source reeks. Constraining the timing cf oil generation and migration within the sub-basins has been hampered by difficulties in assessing thermal maturity using vitrinite reflectance data. Jurassic-Cretaceous formations of predominantly marine origin yield vitrinite reflectance values that are often lower than expected compared to the present day thermal conditions. The two main explanations put forward by workers for this situation are that:a recent increase in thermal gradients has occurred; orthe vitrinite reflectance is suppressed, and this suppression is related to the marine environment of deposition.Thermal history analysis of 65 wells throughout the Barrow and Dampier Sub-basins has confirmed, using multiple maturity parameters, that vitrinite reflectance data are suppressed over large parts of the study area.Thermal history modelling and the confirmation of vitrinite reflectance suppression has enabled revised estimates of pr esent maturity to be made. Maturity levels based on measured reflectance data and values calculated from thermal information exhibit large differences, related to suppression; up to 1,500 m in the depth to the 0.7 per cent R(1 iso-reflectance surface. Vitrinite reflectance suppression, if not taken into account, also strongly affects modelling of uplift and erosion, and the timing of onset of maturity for petroleum generation. Variations of up to 100 Ma have been noted between histories based on measured vitrinite reflectance and those taking vitrinite reflectance suppression into account.

1977 ◽  
Vol 17 (1) ◽  
pp. 58 ◽  
Author(s):  
M. Shibaoka ◽  
A. J. R. Bennett

Three characteristic types of Australian sedimentary basins can be recognized on the basis of depth-reflectance curves. These may be designated as the Cooper, Sydney, and Gippsland Basin types. Characteristic depth-reflectance curves allow an assessment of the depositional and tectonic histories of sedimentary basins to be made. If the geological history and especially the stratigraphy of a basin is well known, it is possible to estimate the maturity which coal or kerogen would have attained at any past or present time. This maturity would be expressed by particular reflectance values of vitrinite. By making actual measurements of vitrinite and kerogen reflectance, the model of maturation can be tested. In this way it has been possible, for a number of basins, to estimate the geological period in which liquid hydrocarbons were generated and the rate at which the maturation process proceeded. The formation of an accumulation of oil is a matter of balance between the supply and loss of oil to and from traps, as well as persistence of traps and migration paths through geological time. The lapse of time after oil generation and the rate of generation are thus most important. The above-mentioned three types of sedimentary basins differ in these respects. Reflectance data can therefore be used not only to estimate the present state of organic maturity, but also in conjunction with the history of sedimentation in the basin, to interpret hydrocarbon generation activity in geological time.


GeoArabia ◽  
2004 ◽  
Vol 9 (4) ◽  
pp. 41-72 ◽  
Author(s):  
Janet K. Pitman ◽  
Douglas Steinshouer ◽  
Michael D. Lewan

ABSTRACT A regional 3-D total petroleum-system model was developed to evaluate petroleum generation and migration histories in the Mesopotamian Basin and Zagros fold belt in Iraq. The modeling was undertaken in conjunction with Middle East petroleum assessment studies conducted by the USGS. Regional structure maps, isopach and facies maps, and thermal maturity data were used as input to the model. The oil-generation potential of Jurassic source-rocks, the principal known source of the petroleum in Jurassic, Cretaceous, and Tertiary reservoirs in these regions, was modeled using hydrous pyrolysis (Type II-S) kerogen kinetics. Results showed that oil generation in source rocks commenced in the Late Cretaceous in intrashelf basins, peak expulsion took place in the late Miocene and Pliocene when these depocenters had expanded along the Zagros foredeep trend, and generation ended in the Holocene when deposition in the foredeep ceased. The model indicates that, at present, the majority of Jurassic source rocks in Iraq have reached or exceeded peak oil generation and most rocks have completed oil generation and expulsion. Flow-path simulations demonstrate that virtually all oil and gas fields in the Mesopotamian Basin and Zagros fold belt overlie mature Jurassic source rocks (vertical migration dominated) and are situated on, or close to, modeled migration pathways. Fields closest to modeled pathways associated with source rocks in local intrashelf basins were charged earliest from Late Cretaceous through the middle Miocene, and other fields filled later when compression-related traps were being formed. Model results confirm petroleum migration along major, northwest-trending folds and faults, and oil migration loss at the surface.


2003 ◽  
Vol 43 (1) ◽  
pp. 59 ◽  
Author(s):  
I.R. Duddy ◽  
B. Erout ◽  
P.F. Green ◽  
P.V. Crowhurst ◽  
P.J. Boult

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.


2003 ◽  
Vol 82 (4) ◽  
pp. 339-349 ◽  
Author(s):  
J. de Jager

AbstractAll Dutch rift basins that formed during Jurassic and Early Cretaceous extension have been inverted during the Late Cretaceous and Early Tertiary. Several inversion pulses occurred more or less simultaneously in all basins. Analysis of vitrinite reflectance data, in combination with fission track and fluid inclusion data show that the magnitude of uplift and erosion generally did not exceed 2 km. Inversion was strongest in the Broad Fourteens, Central Netherlands and West Netherlands basins. The direction of maximum compressive stress was generally not at right angles to the pre-existing fault trends, and resulted in transpressional movements. Within the NW-SE striking basins, dextral strike-slip movements can often be interpreted, which is consistent with a general N-S to NNW-SSE direction of maximum compression related to Alpine structural events. Where no Zechstein salt is present, trends of flower structures formed through reverse reactivation of pre-existing faults. Where the Zechstein salt is thick, re-activated faults could not breach the salt, and a broad uplift of the post-salt succession resulted, while faulting below the salt caused acceleration of halokinesis. In areas where the Zechstein salt was thin, and where the offsets of reverse faults exceeded the thickness of the salt, impressive thrusts with the Zechstein salt as detachment horizon developed. The later Tertiary inversion pulses did not affect all basins, and caused broad basin uplift in the West and Central Netherlands basins while individual faults were no longer reactivated. It appears that due to crustal thickening during the first inversion pulses the crust could become stabilised such that further compression could only be accommodated by broad basin uplift.


2020 ◽  
pp. 75-86
Author(s):  
Sergio Antonio Camargo ◽  
Lauro Correa Romeiro ◽  
Carlos Alberto Mendes Moraes

The present article aimed to test changes in cooling water temperatures of males, present in aluminum injection molds, to reduce failures due to thermal fatigue. In order to carry out this work, cooling systems were studied, including their geometries, thermal gradients and the expected theoretical durability in relation to fatigue failure. The cooling system tests were developed with the aid of simulations in the ANSYS software and with fatigue calculations, using the method of Goodman. The study of the cooling system included its geometries, flow and temperature of this fluid. The results pointed to a significant increase in fatigue life of the mold component for the thermal conditions that were proposed, with a significant increase in the number of cycles, to happen failures due to thermal fatigue.


2021 ◽  
Author(s):  
V. Samoilenko ◽  
I. Goncharov ◽  
P. Trushkov ◽  
N. Oblasov ◽  
M. Veklich ◽  
...  

2021 ◽  
Author(s):  
Shahin Khosrov Akhundov ◽  
Mushfig Farhad Tagiyev ◽  
Arastun Ismail Khuduzade ◽  
Natig Namig Aliyev

Abstract Meso-Cenozoic sedimentary cover in the Middle Kura depression located between the Greater and Lesser Caucasus mountain structures contains numerous oil accumulations. According to studies in the Cretaceous and Paleogene strata, sedimentary organic matter is of mixed clastic-marine origin. Moderate amounts of organic matter have been recorded in the Eocene sediments (on average 0.70%), in the Upper and Lower Cretaceous average values made up 0.39% и 0.42%, respectively. Analysis of bitumoid composition suggests that in a number of areas bitumoids have experienced a widespread movement across the sedimentary strata. The results of measurements on isolated samples indicate that the Cretaceous strata have only advanced to the initial hard-coal stage of organic transformation (0.48-0.55%Ro). On vitrinite reflectance data the Eocene deposits in studied areas of the Middle Kura depression have reached initial (brown-coal) stage of catagenetic transformation (±0.48Ro%; est. paleotemperature of 85°C). Nonetheless, analysis of formation conditions of commercial HC accumulations found earlier in the Eocene strata allows considering them the most prospective in the Middle Kura depression.


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