Planning for success: the Tridacna 3D Seismic Survey, Scott Reef, Western Australia – 3D Ocean Bottom Cable seismic acquisition in a sensitive and remote offshore environment.

2012 ◽  
Author(s):  
Ralph Weiss ◽  
Jeremy Fitzpatrick ◽  
Mark Taylor
Keyword(s):  
Western Australia ◽  
Seismic Survey ◽  
Ocean Bottom ◽  
3D Seismic ◽  
Seismic Acquisition

The challenges of seismic acquisition in a remote and sensitive marine environment: Scott Reef, Western Australia

2009 ◽  
Vol 49 (2) ◽  
pp. 573
Author(s):  
Mark Taylor ◽  
Nick Fitzgerald ◽  
Jeremy Fitzpatrick ◽  
Ralph Weiss
Keyword(s):  
Western Australia ◽  
Seismic Survey ◽  
Ocean Bottom ◽  
Outer Continental Shelf ◽  
Gas Field ◽  
Narrow Channels ◽  
Reef Lagoon ◽  
The North ◽  
Seismic Acquisition ◽  
Water Depths

Woodside Energy Ltd, as operator of the Browse LNG Development, recently acquired two seismic surveys at Scott Reef, Western Australia. The surveys were important steps towards acquiring full seismic coverage over the Torosa gas field, part of which underlies Scott Reef The Maxima 3D marine seismic survey, conducted in late 2007, was a conventional towed streamer survey. This was followed in May 2008 by the Gigas 2D transition zone survey in the shallow waters of north Scott Reef, and Woodside’s first experience with ocean bottom cable (OBC) seismic technology. Each survey presented unique challenges during the planning, regulatory approval and acquisition stages. Scott Reef comprises two coral atolls located on the outer continental shelf of northwest Australia, approximately 400 km north of Broome. The only permanently emergent land is a small sand cay (Sandy Islet, Fig. 1), although the reef crests of both atolls are exposed at low tide. Outside the reefs the seafloor drops away rapidly, with water depths of about 350 m to the east, increasing to more than 1,000 m to the west. South Scott Reef lagoon is open to the north, with water depths increasing to about 50 m before deepening abruptly into the channel between the two reefs. North Scott Reef lagoon is shallower—generally less than 25 m—and is connected to the ocean by two narrow channels. Semi-diurnal tides with a range of up to 4.6 m produce strong tidal currents in and near these channels. Small, steep-sided coral heads, or bombies, are common throughout the lagoons, especially in water less than 25 m deep.

Introduction to this special section: Acquisition and sensing

2019 ◽  
Vol 38 (9) ◽  
pp. 670-670
Author(s):  
Margarita Corzo ◽  
Tim Brice ◽  
Ray Abma
Keyword(s):  
Special Section ◽  
Seismic Survey ◽  
Ocean Bottom ◽  
Total Cost ◽  
Small Boat ◽  
Air Gun ◽  
Seismic Acquisition ◽  
The Cost ◽  
Seismic Images

Seismic acquisition has undergone a revolution over the last few decades. The volume of data acquired has increased exponentially, and the quality of seismic images obtained has improved tremendously. While the total cost of acquiring a seismic survey has increased, the cost per trace has dropped precipitously. Land surveys have evolved from sparse 2D lines acquired with a few dozen receivers to densely sampled 3D multiazimuth surveys. Marine surveys that once may have consisted of a small boat pulling a single cable have evolved to large streamer vessels pulling multiple cables and air-gun arrays and to ocean-bottom detectors that require significant fleets to place the detectors, shoot the sources, and provide support. These surveys collect data that are wide azimuth and typically fairly well sampled.

A case history of a cost effective 3D seismic survey over the Perth Basin, Western Australia

1989 ◽  
Vol 20 (2) ◽  
pp. 229
Author(s):  
S.C. Stewart ◽  
B.J. Evans
Keyword(s):  
Western Australia ◽  
Three Dimensional ◽  
Cost Effective ◽  
Cost Comparison ◽  
Seismic Survey ◽  
3D Seismic ◽  
Seismic Surveying ◽  
History Of ◽  
The Cost ◽  
Funded Research Project

As part of an industry funded research project into the application of the technique of LOFOLD3D land seismic surveying, a four fold three dimensional seismic survey was performed in the Perth Basin at Moora, Western Australia in July 1987. The volume covered an area of four kilometres by just under two kilometres, producing a total of 23,000 common midpoint traces. The objective was to collect and process the data in such a manner that a three dimensional structural interpretation would result, which would be the same as that resulting from a conventional three dimensional survey. A cost comparison indicates that a commercial LOFOLD3D survey would reduce the cost of performing a land 3D survey to an estimated 20% of the full fold equivalent, and the technique therefore offers potential for substantial savings if it is adopted on a commercial basis.

First Hybrid 3D Seismic Survey in Malaysia: A New Paradigm in Ocean Bottom Seismic

2017 ◽  
Author(s):  
Subodh Kumar* ◽  
Sandeep K. Chandola ◽  
Shamsul Shukri ◽  
Stephen Winters ◽  
Bakhtiar Baginda ◽  
...  
Keyword(s):  
Seismic Survey ◽  
Ocean Bottom ◽  
3D Seismic ◽  
New Paradigm

Benefits of Ultra-Dense 3D Spatial Sampling for Seismic Processing and Interpretation

2021 ◽  
Author(s):  
Mohamed Mahgoub ◽  
Guillaume Cambois ◽  
James Cowell ◽  
Suaad Khoori
Keyword(s):  
Model Building ◽  
Velocity Model ◽  
Sensor Data ◽  
Seismic Survey ◽  
Rock Properties ◽  
3D Seismic ◽  
Low Frequencies ◽  
High Resolution Data ◽  
Structural Interpretation ◽  
Seismic Acquisition

Abstract The advances in seismic acquisition systems, especially onshore nodes, have made it possible to acquire ultra-dense 3D surveys at a reasonable cost. This new design enables accurate processing sequences that deliver higher resolution images of the subsurface. These images in turn lead to enhanced structural interpretation and better prediction of rock properties. In 2019, ADNOC and partners acquired an 81 square kilometer ultra-high density pilot survey onshore Abu Dhabi. The receivers were nimble nodes laid out on a 12.5x12.5m grid, which recorded continuously and stored the data on a memory chip. The sources were heavy vibrators sweeping the 2-110 Hz frequency range in 14 seconds on a 12.5x100m grid. 184 million traces per square kilometers did make such small area, the densest 3D seismic survey ever recorded. The single sensor data were expectedly very noisy and the unconstrained simultaneous shooting required elaborate deblending, but we managed these steps with existing tools. The dense 3D receiver grid actually enabled the use of interferometry-based ground-roll attenuation, a technique that is rarely used with conventional data due to inadequate sampling, but that resulted in increased signal-to-noise ratio. The data were migrated directly to depth using a velocity model derived after five iterations of tomographic inversion. The final image gathers were made of 18 reciprocal azimuths with 12.5m offset increment, resulting in 5,000 fold on a 6.25x6.25m grid. The main structural interpretation was achieved during the velocity model building stage. Key horizons were picked after the tomographic iterations and the velocity model was adjusted so that their depth matched the well markers. Anisotropic parameters were adjusted to maintain gather flatness and the new model was fed to the next iteration. This ultimately resulted in flat image gathers and horizons that tied to the wells. The final high-resolution data provided a much crisper image of the target clinoforms and faults. This resulted in a more detailed interpretation of the reservoirs. The data was subjected to pre-stack stratigraphic inversion. The availability of low frequency signal (down to 3 Hz) means that less well constraints are needed for the inversion. Preliminary results are particularly encouraging. Amplitude variations with azimuth have yet to be analyzed but data density bodes very well for the process. Ultra-dense 3D seismic acquisition is feasible and results in a step change in image quality. Structural and stratigraphic interpretation provided a more detailed image of faults and clinoforms. Stratigraphic inversion benefited from the low frequencies of the vibrator source and the increased spatial resolution.

The effects of marine seismic acquisition in a coral reef environment: results from a multi-disciplinary monitoring program at Scott Reef, Western Australia

2009 ◽  
Vol 49 (2) ◽  
pp. 567
Author(s):  
Cameron Grebe ◽  
Luke Smith ◽  
Craig Reid
Keyword(s):  
Western Australia ◽  
Three Dimensional ◽  
Monitoring Program ◽  
Seismic Survey ◽  
Full Data ◽  
Reef Environment ◽  
Seismic Acquisition ◽  
The Indian Ocean ◽  
Coral Reef Environment ◽  
Marine Seismic

In September 2007 Woodside Energy Ltd, as operator of the Browse LNG Development , conducted the Maxima three-dimensional marine seismic survey (Maxima) at Scott Reef, a shelf-emergent coral atoll located in the Indian Ocean approximately 425 km north of Broome, Western Australia Implementation of the survey followed extensive state and Commonwealth environmental approvals processes that began more than 12 months earlier. The survey drew regulator and stakeholder attention, with focus on the uncertainties associated with predicting impacts on Scott Reef marine environment as a result of exposure to airgun noise emissions. Ministerial conditions for approval of the survey concluded that significant impacts were unlikely (Woodside 2008), but required Woodside to address the inherent uncertainties through implementation of a suite of research and monitoring activities prior to, during and after Maxima. Most were completed in on site Scott Reef as part of a field verification study, conducted in advance of the full data acquisition phase of Maxima. These monitoring studies showed that the actual effects of exposure to an airgun array were lower than predicted and established new sound exposure thresholds.

FAULT PLANE RESOLUTION USING THE LOW-FOLD 3D SEISMIC TECHNIQUE OVER WOODADA GAS FIELD, PERTH BASIN, WESTERN AUSTRALIA

1987 ◽  
Vol 27 (1) ◽  
pp. 289
Author(s):  
B.J. Evans ◽  
G.A. Paterson ◽  
S.E. Frey
Keyword(s):  
Western Australia ◽  
Seismic Data ◽  
Joint Venture ◽  
Seismic Survey ◽  
Survey Method ◽  
3D Seismic ◽  
Coherent Noise ◽  
Gas Field ◽  
Single Fold ◽  
Processing Techniques

During August 1984, a conventional 2D seismic line and a single fold 3D seismic survey were recorded over the Woodada Gas Field, North Perth Basin, Western Australia. This survey was a joint venture between the Allied Geophysical Laboratories at the University of Houston and the Exploration Seismology Centre's Field Research Laboratory at the Western Australian Institute of Technology. Previous seismic data were so poor that there was confusion about fault orientation and structure in the survey area. In addition, the fault strike direction and extent were unknown at this location. Consequently, 3D seismic acquisition and processing techniques appeared highly applicable to this geological problem.In general, progressive development of seismic data acquisition methods has been towards higher channel, higher multifold 2D and 3D surveys. However, at the Allied Geophysical Laboratories, processing techniques for single-fold 3D data have been developed using model tank data. This processing technique — LO-FOLD 3D — was used to field trial the method, and to test its ability to define faulting between the gas producing well Indoon 1 and dry step-out well Woodada 9. Previous usage of the single-fold 3D survey method was to delineate reefal structures in the Michigan Basin. Beyond this, no published articles discuss the method.With single-fold data, velocity analysis and coherent noise are a problem. Consequently, 2D bin lines through the 3D volume of data were processed in order to improve the signal to noise ratios. The objective was to delineate the fault orientation in the Carynginia Formation, located between 1.3 and 1.5 seconds. Fault delineation was determined from 2D bin lines and time slices, and is interpreted to run diagonally between the two wells.

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