THE M. AUSTRALIS SANDSTONES, DAMPIER SUB-BASIN, AUSTRALIA

1999 ◽  
Vol 39 (1) ◽  
pp. 104
Author(s):  
A.J. Crowley
Keyword(s):  
Mass Flow ◽  
Western Australia ◽  
Seismic Data ◽  
Shelf Break ◽  
Oil Fields ◽  
Reservoir Quality ◽  
Flow Deposit ◽  
Basin Floor ◽  
A Minor ◽  
Maximum Flooding Surface

Three independent Barremian sandstone units that are characterised by the M. australis palynozone have been identified in the Lewis Trough and Enderby Terrace of the southeastern Dampier Sub-Basin, offshore Western Australia. They constitute a basin-floor fan unit and shelfal transgressive unit that are characterised by the lower Af. australis sub-zone, a shelfal marine to fluvial unit that is characterised by the middle M. australis sub- zone and a shelfal marine unit that is characterised by the upper M. australis sub-zone. The M. australis sandstones are characterised by their excellent reservoir quality, generally common to abundant glauconite content and common provenance.Core, wireline log and seismic data from wells in the Lewis Trough indicate the sediments characterised by the lower M. australis sub-zone form a mass-flow deposit on the regionally extensive Intra-Muderong Hiatus. Transgressive shelfal greensands, interpreted to lie within the latter part of the lower M. australis sub-zone overlie the In tra-Muderong Hiatus on the Enderby Terrace. The glauconitic sandstones characterised by the middle M. australis sub-zone were deposited during a relative highstand and overlie a maximum flooding surface identified in wells on the southern Enderby Terrace. These deposits form the reservoir section for the Wandoo and Stag oil fields. At Wandoo they form a series of seismically definable progrades, whereas at Stag they are the distal toe-sets that lie sub-parallel to the underlying surface. The subsequent sequence boundary is identified in wells and on seismic data as an erosional surface cutting the underlying sediments. Glauconite-rich, transgressive deposits form a fining-up sequence overlie the sequence boundary. Glauconitic sandstones characterised by the upper M. australis sub-zone were deposited at the palaeo- shelf break during a minor regression.

scholarly journals Recreational Harvest of Sharks and Rays in Western Australia Is Only a Minor Component of the Total Harvest

2021 ◽  
Vol 13 (11) ◽  
pp. 6215
Author(s):  
Matias Braccini ◽  
Eva Lai ◽  
Karina Ryan ◽  
Stephen Taylor
Keyword(s):  
Western Australia ◽  
Minor Component ◽  
The North ◽  
Commercial Harvest ◽  
Unknown Status ◽  
Reef Sharks ◽  
Conservation Concern ◽  
Taxonomic Groups ◽  
A Minor ◽  
Port Jackson

Sharks and rays are a global conservation concern with an increasing number of species considered at risk of extinction, mostly due to overfishing. Although the recreational harvest of sharks and rays is poorly documented and generally minimal, it can be comparable to the commercial harvest. In this study, we quantified the recreational harvest of sharks and rays in Western Australia, a region with a marine coastline greater than 20,000 km. A total of 33 species/taxonomic groups were identified, with the harvest dominated by dusky and bronze whalers, blacktip reef sharks, gummy sharks, Port Jackson sharks, wobbegongs, and rays and skates. Eighty-five percent of individuals were released with an unknown status (alive or dead). We found a latitudinal gradient of species composition, with tropical and subtropical species of the genus Carcharhinus dominating in the north and temperate species from a range of families dominating in the south. Overall, our findings showed that the recreational harvest was negligible when compared with commercial landings.

Geostatistical Inversion in Carbonate Reservoirs to Map Reservoir Quality With High Predictability – A Case Study From Onshore Abu Dhabi

2021 ◽  
Author(s):  
S Al Naqbi ◽  
J Ahmed ◽  
J Vargas Rios ◽  
Y Utami ◽  
A Elila ◽  
...  
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
Pore Volume ◽  
Rock Physics ◽  
Static Model ◽  
Reservoir Quality ◽  
Reservoir Properties ◽  
Geostatistical Inversion ◽  
High Predictability ◽  
The Impact

Abstract The Thamama group of reservoirs consist of porous carbonates laminated with tight carbonates, with pronounced lateral heterogeneities in porosity, permeability, and reservoir thickness. The main objective of our study was mapping variations and reservoir quality prediction away from well control. As the reservoirs were thin and beyond seismic resolution, it was vital that the facies and porosity be mapped in high resolution, with a high predictability, for successful placement of horizontal wells for future development of the field. We established a unified workflow of geostatistical inversion and rock physics to characterize the reservoirs. Geostatistical inversion was run in static models that were converted from depth to time domain. A robust two-way velocity model was built to map the depth grid and its zones on the time seismic data. This ensured correct placement of the predicted high-resolution elastic attributes in the depth static model. Rock physics modeling and Bayesian classification were used to convert the elastic properties into porosity and lithology (static rock-type (SRT)), which were validated in blind wells and used to rank the multiple realizations. In the geostatistical pre-stack inversion, the elastic property prediction was constrained by the seismic data and controlled by variograms, probability distributions and a guide model. The deterministic inversion was used as a guide or prior model and served as a laterally varying mean. Initially, unconstrained inversion was tested by keeping all wells as blind and the predictions were optimized by updating the input parameters. The stochastic inversion results were also frequency filtered in several frequency bands, to understand the impact of seismic data and variograms on the prediction. Finally, 30 wells were used as input, to generate 80 realizations of P-impedance, S-impedance, Vp/Vs, and density. After converting back to depth, 30 additional blind wells were used to validate the predicted porosity, with a high correlation of more than 0.8. The realizations were ranked based on the porosity predictability in blind wells combined with the pore volume histograms. Realizations with high predictability and close to the P10, P50 and P90 cases (of pore volume) were selected for further use. Based on the rock physics analysis, the predicted lithology classes were associated with the geological rock-types (SRT) for incorporation in the static model. The study presents an innovative approach to successfully integrate geostatistical inversion and rock physics with static modeling. This workflow will generate seismically constrained high-resolution reservoir properties for thin reservoirs, such as porosity and lithology, which are seamlessly mapped in the depth domain for optimized development of the field. It will also account for the uncertainties in the reservoir model through the generation of multiple equiprobable realizations or scenarios.

Unsupervised machine learning using 3D seismic data applied to reservoir evaluation and rock type identification

2021 ◽  
pp. 1-69
Author(s):  
Marwa Hussein ◽  
Robert R. Stewart ◽  
Deborah Sacrey ◽  
Jonny Wu ◽  
Rajas Athale
Keyword(s):  
Machine Learning ◽  
Seismic Data ◽  
Rock Type ◽  
Seismic Attributes ◽  
Reservoir Quality ◽  
3D Seismic ◽  
Reservoir Properties ◽  
Unsupervised Machine Learning ◽  
Amplitude Data ◽  
3D Seismic Data

Net reservoir discrimination and rock type identification play vital roles in determining reservoir quality, distribution, and identification of stratigraphic baffles for optimizing drilling plans and economic petroleum recovery. Although it is challenging to discriminate small changes in reservoir properties or identify thin stratigraphic barriers below seismic resolution from conventional seismic amplitude data, we have found that seismic attributes aid in defining the reservoir architecture, properties, and stratigraphic baffles. However, analyzing numerous individual attributes is a time-consuming process and may have limitations for revealing small petrophysical changes within a reservoir. Using the Maui 3D seismic data acquired in offshore Taranaki Basin, New Zealand, we generate typical instantaneous and spectral decomposition seismic attributes that are sensitive to lithologic variations and changes in reservoir properties. Using the most common petrophysical and rock typing classification methods, the rock quality and heterogeneity of the C1 Sand reservoir are studied for four wells located within the 3D seismic volume. We find that integrating the geologic content of a combination of eight spectral instantaneous attribute volumes using an unsupervised machine-learning algorithm (self-organizing maps [SOMs]) results in a classification volume that can highlight reservoir distribution and identify stratigraphic baffles by correlating the SOM clusters with discrete net reservoir and flow-unit logs. We find that SOM classification of natural clusters of multiattribute samples in the attribute space is sensitive to subtle changes within the reservoir’s petrophysical properties. We find that SOM clusters appear to be more sensitive to porosity variations compared with lithologic changes within the reservoir. Thus, this method helps us to understand reservoir quality and heterogeneity in addition to illuminating thin reservoirs and stratigraphic baffles.

Combining Seismic Data from Passive and Active Sources for understanding the terrane structure of the Eastern Goldfields, Western Australia

2007 ◽  
Vol 2007 (1) ◽  
pp. 1-4
Author(s):  
Anya M. Reading ◽  
Erdinc Saygin ◽  
Brian L.N. Kennett ◽  
Bruce R. Goleby ◽  
Tanya Fomin ◽  
...  
Keyword(s):  
Western Australia ◽  
Seismic Data

scholarly journals Predicting Potential Zones of Hydrocarbon through Seismic Stratigraphy within the Western Barents Sea, Norway

2017 ◽  
Vol 62 ◽  
pp. 52-60
Author(s):  
Muhammad Rizwan Mughal ◽  
Muhammad Farooq Iqbal ◽  
Irfan Mahmood ◽  
Furqan Mahmud Butt ◽  
Kalim Ullah
Keyword(s):  
Prediction Models ◽  
Barents Sea ◽  
Seismic Stratigraphy ◽  
Well Logs ◽  
Reservoir Quality ◽  
Hydrocarbon Accumulation ◽  
Reservoir Prediction ◽  
The Common ◽  
Maximum Flooding Surface ◽  
Seismic Lines

Stratigraphic play based exploration approach facilitates the development of reservoir prediction models and prospect generation. The present study is carried out along the southern margin of the Loppa High within Hammerfest Basin, Barents Sea, Norway in order to identify the reservoir quality sand in Early Cretaceous age formations along the slope of the high. In this study 2D seismic lines; in which 8 lines are dip and 1 line is strike, and well logs data are interpreted. Outcome is a low-risk exploration technique that is capable of correctly predicting reservoir zones. The stratigraphic trap is identified in the Knurr and Kolje Formations of Adventdalen group, which act as source and seal rock for reservoir respectively. Three stratigraphic surfaces including base of Knurr Formation (sequence boundary), top of Knurr Formation, and Kolje Formation (maximum flooding surface) make a perfect trap for hydrocarbon accumulation. By utilizing the common risk segment analyses, it was identified that the maximum chances of hydrocarbon accumulation are in reservoir zone A and B which lies in up-dip direction.

scholarly journals Application of seismo-stratigraphic interpretation techniques to offshore West Greenland

1988 ◽  
Vol 140 ◽  
pp. 64-66
Author(s):  
J.A Chalmers
Keyword(s):  
Pilot Study ◽  
Seismic Data ◽  
Seismic Interpretation ◽  
Shelf Break ◽  
The West ◽  
Regional Geology ◽  
West Greenland ◽  
Oil Companies ◽  
Greenland Basin ◽  
Basement Ridge

A pilot study is being conducted to determine if the use of seismo-stratigraphic interpretation techniques can increase the understanding af the geology of offshore West Greenland in order to reassess the prospectivity of the area. During the period 1975 to 1979, a number of concessions offshore West Greenland were licensed to various consortia of oil companies to search for petroleum. Some 40 000 km of seismic data were acquired, all of which is now released. Five wells were drilled, all of them dry, and all concessions were relinquished by the industry by 1979. The regional geology of offshore West Greenland has been summarised by Manderscheid (1980) and Henderson et al. (1981). They show the West Greenland Basin to consist of fairly uniformly westward dipping sediments bordered near the shelf break by a basement ridge. These authors used what may be termed 'conventional' techniques of seismic interpretation. However, since that time the techniques of seismo-stratigraphy (Vail et al., 1977; Hubbard et al., 1985) have become established. They are now being applied to study seismic data acquired during the mid-1970s.

The Influence of Main Factors on Deepwater Sediments

2021 ◽  
Author(s):  
Anton Khitrenko ◽  
Adelia Minkhatova ◽  
Vladimir Orlov ◽  
Dmitriy Kotunov ◽  
Salavat Khalilov
Keyword(s):  
Sequence Stratigraphy ◽  
Deep Water ◽  
Western Siberia ◽  
Reservoir Characterization ◽  
Water Reservoir ◽  
Shelf Break ◽  
Sediment Supply ◽  
Reservoir Quality ◽  
Geological Uncertainty ◽  
Forced Regression

Abstract Western Siberia is a unique petroleum basin with exclusive geological objects. Those objects allow us to test various methods of sequence stratigraphy, systematization and evaluation approaches for reservoir characterization of deep-water sediments. Different methods have potential to decrease geological uncertainty and predict distribution and architecture of deep-water sandstone reservoir. There are many different parameters that could be achieved through analysis of clinoform complex. Trajectories of shelf break, volume of sediment supply and topography of basin influence on architecture of deep-water reservoir. Based on general principles of sequence stratigraphy, three main trajectories changes shelf break might be identified: transgression, normal regression and forced regression. And each of them has its own distinctive characteristics of deepwater reservoir. However, to properly assess the architecture of deepwater reservoir and potential of it, numerical characteristics are necessary. In our paper, previously described parameters were analyzed for identification perspective areas of Achimov formation in Western Siberia and estimation of geological uncertainty for unexplored areas. In 1996 Helland-Hansen W., Martinsen O.J. [5] described different types of shoreline trajectory. In 2002 Steel R.J., Olsen T. [11] adopted types of shoreline trajectory for identification of truncation termination. O. Catuneanu (2009) [1] summarize all information with implementation basis of sequence stratigraphy. Over the past decade, many geoscientists have used previously published researches to determine relationship between geometric structures of clinoforms and architecture of deep-water sediments and its reservoir quality. Significant amount of publications has allowed to form theoretical framework for the undersanding sedimentation process and geometrical configuration of clinoforms. However, there is still no relationship between sequence stratigraphy framework of clinoroms and reservoir quality and its uncertainty, which is necessary for new area evaluation.

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