CONTROLS ON SEASPRAY GROUP SONIC VELOCITIES IN THE GIPPSLAND BASIN—A MULTI-DISCIPLINARY APPROACH TO THE CANYON SEISMIC VELOCITY PROBLEM

2000 ◽  
Vol 40 (1) ◽  
pp. 293 ◽  
Author(s):  
G.R. Holdgate ◽  
M.W. Wallace ◽  
J. Daniels S.J. Gallagher ◽  
J.B. Keene ◽  
A.J. Smith

Seaspray Group carbonate sediments of Oligocene to Recent age overlie the main hydrocarbon producing Upper Cretaceous to Eocene Latrobe Group in the offshore Gippsland Basin. Their sonic complexity creates major difficulties for hydrocarbon exploration. Carbonate facies are divisible into three subgroups based on seismic character, sonic logs, velocity profiles, carbonate content, petrologic character and age. The oldest unit is the Angler Subgroup that consists of carbonate pelagic marls (CaC03 70%) with interbedded clastic-rich units.Zones of high velocity (>3,000m/s) are restricted to the deeply buried parts of the Albacore Subgroup, at TWT's greater than 0.8 seconds. The characteristics of this high velocity facies are: a composition of fine grained bioclast-rich packstones and wackestones with less than 10% silt sized quartz; the carbonate content exceeds 60%; the intervals are prone to cementation and are stylolitised; they are diachronous (i.e. cut across seismic boundaries); velocities progressively increase with depth; highest velocities occur where the unit is thickest towards the centre of the basin; velocity increases laterally with steepness of angle on downlap surfaces due to coarser grain sizes and inferred greater initial porosity; and velocities increase with stratigraphic age in the Albacore Subgroup. Regardless of burial depth the Angler and Hapuku Subgroups contain no significantly high velocity zones.An empirical relationship derived from this data set provides a basis for re-interpreting average velocity to the top of the Latrobe Group in areas underlying high velocity canyon-fill sediments.

1973 ◽  
Vol 13 (1) ◽  
pp. 68
Author(s):  
Jorg Bein ◽  
Brian R. Griffith ◽  
Andrew K. Svalbe

The Kingfish field, currently Australia's largest producing oil field, lies 48 miles offshore southeastern Victoria in 250 ft of water. The field occurs within a large, essentially, east-west trending topographic high on the Latrobe unconformity surface sealed by fine grained clastics of the Upper Eocene Gurnard and Oligocene Lakes Entrance Formations. The reservoir itself is formed by Lower Eocene sediments of interdeltaic origin.The discovery well, Kingfish 1, was spudded on 6 April 1967. This well indicated the severity of a suspected seismic velocity gradient, a function of high velocity channel deposits in Miocene sediments overlying the crest of the Latrobe unconformity surface. Additional seismic coverage and two outpost wells provided sufficient structural and stratigraphic control to define a commercial oil field having a maximum of 270 ft of vertical relief over an area of some 28 sq mi at the oil-water contact of 7,566 ft subsea.Following completion of the 42 well development drilling program for the A and B platforms the Kingfish oil field was put on stream on 21 April 1971. Proved and probable reserves have been initially estimated at 1,060 MM STB. The field has flowed oil at rates in excess of 180,000 STB/D for a cumulative production to the end of 1972 of 83 MM STB.


2018 ◽  
Vol 6 (4) ◽  
pp. SO17-SO29 ◽  
Author(s):  
Yaneng Luo ◽  
Handong Huang ◽  
Yadi Yang ◽  
Qixin Li ◽  
Sheng Zhang ◽  
...  

In recent years, many important discoveries have been made in the marine deepwater hydrocarbon exploration in the South China Sea, which indicates the huge exploration potential of this area. However, the seismic prediction of deepwater reservoirs is very challenging because of the complex sedimentation, the ghost problem, and the low exploration level with sparse wells in deepwater areas. Conventional impedance inversion methods interpolate the low frequencies from well-log data with the constraints of interpreted horizons to fill in the frequency gap between the seismic velocity and seismic data and thereby recover the absolute impedance values that may be inaccurate and cause biased inversion results if wells are sparse and geology is complex. The variable-depth streamer seismic data contain the missing low frequencies and provide a new opportunity to remove the need to estimate the low-frequency components from well-log data. Therefore, we first developed a broadband seismic-driven impedance inversion approach using the seismic velocity as initial low-frequency model based on the Bayesian framework. The synthetic data example demonstrates that our broadband impedance inversion approach is of high resolution and it can automatically balance between the inversion resolution and stability. Then, we perform seismic sedimentology stratal slices on the broadband seismic data to analyze the depositional evolution history of the deepwater reservoirs. Finally, we combine the broadband amplitude stratal slices with the impedance inversion results to comprehensively predict the distribution of deepwater reservoirs. Real data application results in the South China Sea verify the feasibility and effectiveness of our method, which can provide a guidance for the future deepwater hydrocarbon exploration in this area.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yousif M. Makeen ◽  
Xuanlong Shan ◽  
Mutari Lawal ◽  
Habeeb A. Ayinla ◽  
Siyuan Su ◽  
...  

AbstractThe Abu Gabra and Bentiu formations are widely distributed within the interior Muglad Basin. Recently, much attention has been paid to study, evaluate and characterize the Abu Gabra Formation as a proven reservoir in Muglad Basin. However, few studies have been documented on the Bentiu Formation which is the main oil/gas reservoir within the basin. Therefore, 33 core samples of the Great Moga and Keyi oilfields (NE Muglad Basin) were selected to characterize the Bentiu Formation reservoir using sedimentological and petrophysical analyses. The aim of the study is to de-risk exploration activities and improve success rate. Compositional and textural analyses revealed two main facies groups: coarse to-medium grained sandstone (braided channel deposits) and fine grained sandstone (floodplain and crevasse splay channel deposits). The coarse to-medium grained sandstone has porosity and permeability values within the range of 19.6% to 32.0% and 1825.6 mD to 8358.0 mD respectively. On the other hand, the fine grained clay-rich facies displays poor reservoir quality as indicated by porosity and permeability ranging from 1.0 to 6.0% and 2.5 to 10.0 mD respectively. A number of varied processes were identified controlling the reservoir quality of the studies samples. Porosity and permeability were enhanced by the dissolution of feldspars and micas, while presence of detrital clays, kaolinite precipitation, iron oxides precipitation, siderite, quartz overgrowths and pyrite cement played negative role on the reservoir quality. Intensity of the observed quartz overgrowth increases with burial depth. At great depths, a variability in grain contact types are recorded suggesting conditions of moderate to-high compactions. Furthermore, scanning electron microscopy revealed presence of micropores which have the tendency of affecting the fluid flow properties in the Bentiu Formation sandstone. These evidences indicate that the Bentiu Formation petroleum reservoir quality is primarily inhibited by grain size, total clay content, compaction and cementation. Thus, special attention should be paid to these inhibiting factors to reduce risk in petroleum exploration within the area.


2021 ◽  
Vol 60 (1) ◽  
pp. 31-50
Author(s):  
Ryad Darawcheh ◽  
Riad Al Ghazzi ◽  
Mohamad Khir Abdul-wahed

In this research, a data set of horizontal GPS coseismic displacement in the near-field has been assembled around the world in order to investigate a potential relationship between the displacement and the earthquake parameters. Regression analyses have been applied to the data of 120 interplate earthquakes having the magnitude (Mw 4.8-9.2). An empirical relationship for prediction near-field horizontal GPS coseismic displacement as a function of moment magnitude and the distance between hypocenter and near field GPS station has been established using the multi regression analysis. The obtained relationship allows assessing the coseismic displacements associated with some large historical earthquakes occurred along the Dead Sea fault system. Such a fair relationship could be useful for assessing the coseismic displacement at any point around the active faults.


2021 ◽  
pp. 1-28
Author(s):  
Wei Xu ◽  
Zhengyu Li ◽  
Huiyong Li ◽  
Can Zhang ◽  
Meng Zhao ◽  
...  

There are various types of mixed siliciclastic-carbonate sediments developed in the Bohai Sea area during the period of the first to second member of the Shahejie Formation (E2s1-2) of the Paleocene. We have concluded that the period of E2s1-2 was very suitable for the development of carbonate minerals and organisms because of the stable tectonic background, the weak siliciclastic influence of large source systems outside the basin, and the high salinity of the water. There were many local uplifts inside the basin during E2s1-2, and the source area, supply direction, and quantity of the local provenance varied greatly. We summarized that the mixed sediments generally developed in the intermittent and stagnant periods of the source supply, or on the flank or distal end of the source supply direction due to the absence of direct interference of terrigenous clasts. To a large extent, the formation of different types of mixed deposits is controlled by the different spatiotemporal relationship with siliciclastic supply. The background of strong source supply led to the formation of large-scale mixed deposits that were mainly composed of terrigenous clasts. Mixed deposits are mainly composed of organisms and carbonate with relatively large depositional thickness formed on the flank of source supply in the steep slope area. On the flank of source supply in the gentle slope belt, thinner mixed deposits with terrigenous clasts mainly formed and thin-layer carbonate clastic-dominated deposits formed on abandoned deltas. On the uplift of the buried hill far away from the provenance, thick mixed deposits mainly composed of bioclastic were formed whereas fine-grained mixed deposits formed under the low-energy argillaceous background.


Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 209
Author(s):  
Gabriel D. Gwanmesia ◽  
Matthew L. Whitaker ◽  
Lidong Dai ◽  
Alwin James ◽  
Haiyan Chen ◽  
...  

We measured the elastic velocities of a synthetic polycrystalline β-Mg2SiO4 containing 0.73 wt.% H2O to 10 GPa and 600 K using ultrasonic interferometry combined with synchrotron X-radiation. Third-order Eulerian finite strain analysis of the high P and T data set yielded Kso = 161.5(2) GPa, Go = 101.6(1) GPa, and (∂Ks/∂P)T = 4.84(4), (∂G/∂P)T = 1.68(2) indistinguishable from Kso = 161.1(3) GPa, Go = 101.4(1) GPa, and (∂Ks/∂P)T = 4.93(4), (∂G/∂P)T = 1.73(2) from the linear fit. The hydration of the wadsleyite by 0.73 wt.% decreases Ks and G moduli by 5.3% and 8.6%, respectively, but no measurable effect was noted for (∂Ks/∂P)T and (∂G/∂P)T. The temperature derivatives of the Ks and G moduli from the finite strain analysis (∂KS/∂T)P = −0.013(2) GPaK−1, (∂G/∂T)P = −0.015(0.4) GPaK−1, and the linear fit (∂KS/∂T)P = −0.015(1) GPaK−1, (∂G/∂T)P = −0.016(1) GPaK−1 are in agreement, and both data sets indicating the |(∂G/∂T)P| to be greater than |(∂KS/∂T)P|. Calculations yield ∆Vp(α-β) = 9.88% and ∆VS(α-β) = 8.70% for the hydrous β-Mg2SiO4 and hydrous α-Mg2SiO4, implying 46–52% olivine volume content in the Earth’s mantle to satisfy the seismic velocity contrast ∆Vs = ∆VP = 4.6% at the 410 km depth.


2020 ◽  
Author(s):  
Hongjie Zhou ◽  
Shambhu Sharma ◽  
Alessandro Amodio ◽  
Noel Boylan ◽  
Peter Gaunt

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Jintao Wang ◽  
Mingxia Shen ◽  
Longshen Liu ◽  
Yi Xu ◽  
Cedric Okinda

Digestive diseases are one of the common broiler diseases that significantly affect production and animal welfare in broiler breeding. Droppings examination and observation are the most precise techniques to detect the occurrence of digestive disease infections in birds. This study proposes an automated broiler digestive disease detector based on a deep Convolutional Neural Network model to classify fine-grained abnormal broiler droppings images as normal and abnormal (shape, color, water content, and shape&water). Droppings images were collected from 10,000 25-35-day-old Ross broiler birds reared in multilayer cages with automatic droppings conveyor belts. For comparative purposes, Faster R-CNN and YOLO-V3 deep Convolutional Neural Networks were developed. The performance of YOLO-V3 was improved by optimizing the anchor box. Faster R-CNN achieved 99.1% recall and 93.3% mean average precision, while YOLO-V3 achieved 88.7% recall and 84.3% mean average precision on the testing data set. The proposed detector can provide technical support for the detection of digestive diseases in broiler production by automatically and nonintrusively recognizing and classifying chicken droppings.


2013 ◽  
Vol 53 (2) ◽  
pp. 460
Author(s):  
Nick Hoffman ◽  
Natt Arian

Carbon dioxide geosequestration requires a detailed understanding of the whole sedimentary section, with particular emphasis on topseals and intraformational seals. Hydrocarbon exploration is more focused on reservoirs but requires a similar basin understanding. This extended abstract reviews the knowledge gained from petroleum exploration in the Gippsland Basin to The CarbonNet Project’s exploration program for CO2 storage. The Ninety Mile Beach on the Gippsland coast is a prominent modern-day sand fairway where longshore drift transports sediments north-eastwards along a barrier-bar system, trapping lake systems behind the coastal strip. This beach is only 10,000 years old (dating to the last glacial rise of sea level) but is built on a platform of earlier beaches that can be traced back almost 90 million years to the initiation of Latrobe Group deposition in the Gippsland Basin. Using a recently compiled and open-file volume of merged 3D seismic surveys, the authors show the evolution of the Latrobe shoreline can be mapped continuously from the Upper Cretaceous to the present day. Sand fairways accumulate as a barrier-bar system at the edge of a steadily subsiding marine embayment, with distinct retrogradational geometries. Behind the barrier system, a series of trapped lakes and lagoons are mapped. In these, coal swamps, extensive shales, and tidal sediments were deposited at different stages of the sea-level curve, while fluvial systems prograded through these lowlands. Detailed 3D seismic extractions show the geometry, orientation and extent of coals, sealing shales, fluvial channels, and bayhead deltas. Detailed understanding of these reservoir and seal systems outlines multi-storey play fairways for hydrocarbon exploration and geosequestration. Use of modern basin resource needs careful coordination of activity and benefits greatly from established data-sharing practices.


Author(s):  
Horst G. Brandes

Permeability values for a range of fine-grained deep-sea sediments are presented and evaluated in terms of index properties such as plasticity, grain size and carbonate content. It is found that whereas clay-rich sediments have similar permeabilities to those of equivalent land-based fine-grained soils, the presence of volcanic, carbonate and other non-clay fractions tends to increase permeability somewhat. Volcanic silty-clayey soils from Hawaii have comparable permeability values, although they can be slightly more permeable.


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