Conodont Biostratigraphy of Ordovician Deep-Water Turbiditic Sequences in Eastern Australia—A New Biozonal Scheme for the Open-Sea Realm

2021 ◽  
Vol 32 (3) ◽  
pp. 486-500
Author(s):  
Yong Yi Zhen ◽  
Ian G. Percival ◽  
Phil Gilmore ◽  
Jodie Rutledge ◽  
Liann Deyssing
Keyword(s):  
Deep Water ◽  
Conodont Biostratigraphy ◽  
Open Sea ◽  
Eastern Australia

Riser Response Based Optimal Positioning of Deep-Water Vessels

2005 ◽  
Author(s):  
Christopher Hoen
Keyword(s):  
Dynamic Response ◽  
Deep Water ◽  
Attractive Alternative ◽  
Practical Applications ◽  
Regression Curves ◽  
Coiled Tubing ◽  
Transverse Current ◽  
Open Sea ◽  
Slow Drift ◽  
On Line

The present paper discusses the mathematical modeling of risers and riser-like structures applied in a positioning context for deep-water floating vessels. The main purpose of the paper is to show that an estimate for the optimal vessel position, sufficient for most practical applications, is obtained from measurements of the riser inclinations or related parameters at lower end, and optionally upper end, through a solution based on the variably tensioned beam differential equation. Due to the ease of implementation this solution is well suited for direct application in on-line riser monitoring systems. The method is an attractive alternative to on-line FE-analyses, application of pre-computed regression curves based on idealized loading or black-box neural networks, which has been proposed by others to be applied as basis for interpretation of the measured riser responses. The basic idea behind the method is based on the observation that the riser inclinations or stress-joint moments at upper and lower end have mainly two causes. Firstly an effect caused by the position of the riser top end relative to the wellhead due to permanent vessel offset and slow drift vessel motions, and secondly the effects of transverse current down the riser. The general theory behind the method will be outlined. It will then be shown how the method adapts to drilling-risers with flex-joints, risers with stress-joints and also to the special case of well intervention with coiled tubing in open sea without applying a work-over or marine riser. The performance of the method is illustrated using simulated vessel and riser dynamic response data. The simulations are performed for selected vessel types both for deep-water and shallower waters applying state-of-the-art software for simulation of the riser and vessel dynamic response in random sea states.

The Bordeaux Port Radar

1964 ◽  
Vol 17 (4) ◽  
pp. 399-405
Author(s):  
A. Girardin
Keyword(s):  
Deep Water ◽  
Gironde Estuary ◽  
Seaward Side ◽  
Open Sea ◽  
Water Springs ◽  
Inner Channel ◽  
East West

At the end of 1963, to assist ships making use of the extensive facilities in the Gironde estuary, the port of Bordeaux installed surveillance radar covering the mouth of the Gironde. As it is still too early to assess its potentialities, this paper describes the technical arrangements and makes some general comments on the use of radar, suggested by the new installation.Ships approaching the Gironde estuary from the open sea follow the buoyed channel from the landfall buoy BXA, 18 kilometres west of Pointe de la Coubre. After picking up the pilot they enter the western or outer entrance passage, whose seaward termination lies 8 kilometres from the coast. This provides a dredged channel, 800 metres wide and 3500 metres long, running east–west. The depth of 12 metres at low water springs enables ships to cross the annular river bar separating the deep water on the seaward side from the mud banks at the mouth of the inner channel.

Exploring New Zealand's marine territory

2011 ◽  
Vol 51 (1) ◽  
pp. 549 ◽  
Author(s):  
Chris Uruski
Keyword(s):  
New Zealand ◽  
Deep Water ◽  
Seismic Data ◽  
East Coast ◽  
Sedimentary Basins ◽  
Petroleum Exploration ◽  
Seismic Survey ◽  
Data Set ◽  
Eastern Australia ◽  
Deep Water Part

Around the end of the twentieth century, awareness grew that, in addition to the Taranaki Basin, other unexplored basins in New Zealand’s large exclusive economic zone (EEZ) and extended continental shelf (ECS) may contain petroleum. GNS Science initiated a program to assess the prospectivity of more than 1 million square kilometres of sedimentary basins in New Zealand’s marine territories. The first project in 2001 acquired, with TGS-NOPEC, a 6,200 km reconnaissance 2D seismic survey in deep-water Taranaki. This showed a large Late Cretaceous delta built out into a northwest-trending basin above a thick succession of older rocks. Many deltas around the world are petroleum provinces and the new data showed that the deep-water part of Taranaki Basin may also be prospective. Since the 2001 survey a further 9,000 km of infill 2D seismic data has been acquired and exploration continues. The New Zealand government recognised the potential of its frontier basins and, in 2005 Crown Minerals acquired a 2D survey in the East Coast Basin, North Island. This was followed by surveys in the Great South, Raukumara and Reinga basins. Petroleum Exploration Permits were awarded in most of these and licence rounds in the Northland/Reinga Basin closed recently. New data have since been acquired from the Pegasus, Great South and Canterbury basins. The New Zealand government, through Crown Minerals, funds all or part of a survey. GNS Science interprets the new data set and the data along with reports are packaged for free dissemination prior to a licensing round. The strategy has worked well, as indicated by the entry of ExxonMobil, OMV and Petrobras into New Zealand. Anadarko, another new entry, farmed into the previously licensed Canterbury and deep-water Taranaki basins. One of the main results of the surveys has been to show that geology and prospectivity of New Zealand’s frontier basins may be similar to eastern Australia, as older apparently unmetamophosed successions are preserved. By extrapolating from the results in the Taranaki Basin, ultimate prospectivity is likely to be a resource of some tens of billions of barrels of oil equivalent. New Zealand’s largely submerged continent may yield continent-sized resources.

Austrarturellidae (Crustacea : Isopoda : Valvifera), a new family from Australasia

1992 ◽  
Vol 6 (4) ◽  
pp. 843 ◽  
Author(s):  
GCB Poore ◽  
TM Bardsley
Keyword(s):  
New Zealand ◽  
Continental Shelf ◽  
Deep Water ◽  
Type Species ◽  
Proximal Part ◽  
New Family ◽  
Eastern Australia ◽  
The Family ◽  
North Eastern

The family Austrarcturellidae is established for Austrarcturella, gen. nov., Abyssarcturella, gen. nov., Pseudarcturella Tattersall (1921) and Scyllarcturella, gen. nov. Males of this family share a uniquely modified first pleopod in which the exopod has a lateral secondary ramus. The pleotelson is usually of a unique inverted flat-bottomed boat-shape, and the dactyli of pereopods 2 and 3 have a minute proximal part and elongate unguis. The genus Pseudarcturella Tattersall (1921) is redefined; its type species, P. chiltoni Tattersall, is redescribed and P. crenulata, sp. nov. added. Thirteen species of Austrarcturella, gen. nov. are described from the Australian continental shelf and slope: A. oculata (Beddard) (type species), A. aphelura, sp. nov., A. brychia, sp. nov., A. callosa, sp. nov., A. cava (Hale), A. corona, sp. nov., A. hirsuta, sp. nov., A. inornata, sp. nov., A. macrokola, sp. nov., A. pictila, sp. nov., A. sexspinosa, sp. nov., A. spinipes, sp, nov. and A. thetidis, sp. nov. One further species, A. galathea, sp, nov., is described from New Zealand. Abyssarcturella, gen. nov. is diagnosed and two species from deep water in eastern Australia are described: A. panope, sp. nov. (type species) and A. cidaris, sp. nov. Scyllarcturella, gen, nov. is diagnosed for S. falcata, sp. nov. from deep water in north-eastern Australia. Keys to all taxa are presented and their distributions are briefly discussed.

Comparison of life histories of two deep-water sharks from eastern Australia: the piked spurdog and the Philippine spurdog

2016 ◽  
Vol 67 (10) ◽  
pp. 1546 ◽  
Author(s):  
Cassandra L. Rigby ◽  
Ross K. Daley ◽  
Colin A. Simpfendorfer
Keyword(s):  
Life History ◽  
Deep Water ◽  
Life Histories ◽  
Growth Models ◽  
New South ◽  
South Wales ◽  
Eastern Australia ◽  
History Of ◽  
Males And Females ◽  
Species Specific

Deep-water sharks have low biological productivity and are vulnerable to exploitation with species-specific regional life history required to enable effective management. The present study describes the life history of two squalids collected from Australia: (1) the piked spurdog (Squalus megalops) from the tropical Great Barrier Reef; and (2) the Philippine spurdog (S. montalbani) from New South Wales. Maximum observed ages for males and females were 18 and 25 years for S. megalops and 28 and 27 years for S. montalbani. Multiple growth models were all well supported and indicated very slow growth rates for both species. The tropical S. megalops population was smaller and older at maturity than previously reported temperate populations. Males were mature at 352-mm stretched total length (LST) and 12.6 years, whereas females were mature at 422mm LST and 19.1 years. Squalus montalbani males were mature at 700mm LST and 21.8 years, whereas females were mature at 800mm LST and 26 years. Fecundity was lower for S. megalops than S. montalbani with two to three compared with nine to 16 embryos. Both species have a conservative life history, although in the event of overfishing the longer-lived, later-maturing and deeper-dwelling S. montalbani is likely to take longer to recover than S. megalops.

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