Malacca Strait 3D Seismic Survey – A Comprehensive Approach to Seismic Acquisition in Transition Zones

2018 ◽  
Author(s):  
W. O. Ardjakusumah
Keyword(s):  
Comprehensive Approach ◽  
Seismic Survey ◽  
3D Seismic ◽  
Transition Zones ◽  
Seismic Acquisition ◽  
Malacca Strait

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.

Lessons Learned From the World's Largest Continuous Onshore and Offshore 3D Seismic Survey

2021 ◽  
Author(s):  
Saif Ali Al Mesaabi ◽  
Guillaume Marie Cambois ◽  
James Cowell ◽  
David Arnold ◽  
Mohamed Fawzi Boukhanfra ◽  
...  
Keyword(s):  
Low Frequency ◽  
High Energy ◽  
Lessons Learned ◽  
Seismic Survey ◽  
3D Seismic ◽  
Low Frequencies ◽  
The Status ◽  
Seismic Acquisition ◽  
Abu Dhabi Emirate ◽  
Legacy Data

Abstract In 2017 ADNOC decided to cover the entire Abu Dhabi Emirate, onshore and offshore, with high- resolution and high-fold 3D seismic. Acquisition of the world's largest continuous seismic survey started in late 2018 and is around 77% complete at the time of writing. Data processing is well under way and interpretation of the first delivered 3D cubes is ongoing. Now is an opportune time to review the status of this gigantic project and draw preliminary lessons. Comparison with legacy data shows a massive improvement in deep imaging, which was one of the main objectives of this survey. The basement can clearly be interpreted, while it is hardly visible on legacy data being covered with high energy multiples. A thorough analysis demonstrated that increased offset is the main reason for the uplift. The large fold and the low frequency sweep also help recover signal down to 3 Hz. This extends the bandwidth in the low frequencies by one to two octaves compared to legacy data, which tremendously benefits structural interpretation and stratigraphic inversion.

Optimization Of A 3D Seismic Survey Onshore Abu Dhabi - From Field Tests To Final Design

2000 ◽  
Author(s):  
Abu Baker Al Jeelani ◽  
Samer Marmash ◽  
Abdul Salam Bin Ishaq ◽  
Ahmed Al-Shaikh ◽  
Eric Kleiss ◽  
...  
Keyword(s):  
Field Tests ◽  
Seismic Survey ◽  
Abu Dhabi ◽  
3D Seismic ◽  
Final Design

Exploring for stratigraphic traps in the Patchawarra Formation, Cooper Basin: an integrated seismic methodology

2018 ◽  
Vol 58 (2) ◽  
pp. 779
Author(s):  
Alexandra Bennett
Keyword(s):  
Complex Geometry ◽  
Imaging Techniques ◽  
South Australia ◽  
Seismic Interpretation ◽  
Seismic Survey ◽  
3D Seismic ◽  
Seismic Resolution ◽  
Seismic Reflectivity ◽  
Seismic Area ◽  
Cooper Basin

The Patchawarra Formation is characterised by Permian aged fluvial sediments. The conventional hydrocarbon play lies within fluvial sandstones, attributed to point bar deposits and splays, that are typically overlain by floodbank deposits of shales, mudstones and coals. The nature of the deposition of these sands has resulted in the discovery of stratigraphic traps across the Western Flank of the Cooper Basin, South Australia. Various seismic techniques are being used to search for and identify these traps. High seismic reflectivity of the coals with the low reflectivity of the relatively thin sands, often below seismic resolution, masks a reservoir response. These factors, combined with complex geometry of these reservoirs, prove a difficult play to image and interpret. Standard seismic interpretation has proven challenging when attempting to map fluvial sands. Active project examples within a 196 km2 3D seismic survey detail an evolving seismic interpretation methodology, which is being used to improve the delineation of potential stratigraphic traps. This involves an integration of seismic processing, package mapping, seismic attributes and imaging techniques. The integrated seismic interpretation methodology has proven to be a successful approach in the discovery of stratigraphic and structural-stratigraphic combination traps in parts of the Cooper Basin and is being used to extend the play northwards into the 3D seismic area discussed.

scholarly journals 3D Seismic Acquisition Technology and Effect in HX Volcanic Area in Liaohe Depression

2016 ◽  
Vol 07 (07) ◽  
pp. 944-955 ◽  
Author(s):  
Haibo Wang ◽  
Bing Liu ◽  
Qiwei Zou ◽  
Lizhi Sun ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Volcanic Area ◽  
3D Seismic ◽  
Seismic Acquisition ◽  
Liaohe Depression

On the reconstruction of the shape of a seismic streamer

Geophysics ◽  
2010 ◽  
Vol 75 (1) ◽  
pp. H1-H6
Author(s):  
Bruno Goutorbe ◽  
Violaine Combier
Keyword(s):  
A Priori ◽  
Synthetic Data ◽  
Seismic Survey ◽  
Random Errors ◽  
Generalized Inversion ◽  
Reconstruction Methods ◽  
Seismic Acquisition ◽  
Marine Seismic ◽  
Gps Devices ◽  
Vessel Reconstruction

In the frame of 3D seismic acquisition, reconstructing the shape of the streamer(s) for each shot is an essential step prior to data processing. Depending on the survey, several kinds of constraints help achieve this purpose: local azimuths given by compasses, absolute positions recorded by global positioning system (GPS) devices, and distances calculated between pairs of acoustic ranging devices. Most reconstruction methods are restricted to work on a particular type of constraint and do not estimate the final uncertainties. The generalized inversion formalism using the least-squares criterion can provide a robust framework to solve such a problem — handling several kinds of constraints together, not requiring an a priori parameterization of the streamer shape, naturally extending to any configuration of streamer(s), and giving rigorous uncertainties. We explicitly derive the equations governing the algorithm corresponding to a marine seismic survey using a single streamer with compasses distributed all along it and GPS devices located on the tail buoy and on the vessel. Reconstruction tests conducted on several synthetic examples show that the algorithm performs well, with a mean error of a few meters in realistic cases. The accuracy logically degrades if higher random errors are added to the synthetic data or if deformations of the streamer occur at a short length scale.

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