GeoStreamer X in the Viking Graben Illuminates Complex Targets
Author: Kai Fløistad, Julien Oukili
GeoExpro - 8 June 2020
To meet the industry demand for improved subsurface insight at a reduced cost and with faster turnaround time than ocean bottom surveys, PGS deployed a pioneering acquisition configuration in the Viking Graben in the autumn of 2019. Three months after the last shot on the GeoStreamer X survey in the Viking Graben, the early-out multi-azimuth (MAZ) PSDM seismic stack was delivered to pre-funders. From an interpreter’s point of view the results are stunning, and what started as a novel concept now provides new insight to geoscience teams in near-field exploration, appraisal and development.
There are many targets in the area, ranging from Eocene sand injectites to fractured basement, and an approach integrating survey design, imaging solutions and quantitative interpretation has enabled a significant improvement in the resolution of these reservoirs. The main imaging challenges are the large shallow channels and massive sand mounds in the Miocene as these introduce shadow zones beneath them. Eocene cemented sand injectites, called V-brights, have anomalously high velocities which historically have been very difficult to estimate. Deeper, a thin, rugose Cretaceous chalk layer causes multiples and dispersion of the seismic energy.
Seismic processing parameter mining – the past may be the key to the present
Author: Tony Martin, Andrew Long, Suhail Butt, Khairom Baharom
First Break - 1 June 2020
The authors describe a proof-of-concept test, mining an historical database to extract appropriate parameter choices for seismic processing. Using quantitative metrics, they compare the results of using the mined parameters with a full-integrity project, and draw conclusions on whether this approach can bypass testing and reduce turnaround times.
Orphan Basin, Canada | From Regional Prospect Screening to Reliable Reservoir Attributes Estimation
Author: Scott Opdyke, Cyrille Reiser, Tiago Alcantara, Elena Polyaeva
GeoExpro - 4 May 2020
A new, high quality regional dataset covering 22 469 sq. km is enabling the identification of important petroleum system elements in the underexplored Orphan Basin, offshore eastern Canada. Block evaluations for the upcoming license rounds can be performed with confidence with this multi-sensor broadband seismic data and its reliable pre-stack attributes. The most recently acquired part of this regional dataset is the North Tablelands survey, acquired in 2019 as an extension of the Tablelands and Long Range surveys, which were shot in 2017–2018 by PGS and TGS. Fast-track data was delivered just five weeks after the last shot of the North Tablelands survey. A full integrity volume is available now and provides a single, continuous high-resolution seismic dataset available for licensing early next year, encompassing the Long Range, Tablelands and North Tablelands surveys.
The music of marine seismic: A marine vibrator system based on folded surfaces
Author: Okwudili Orji, Mattias Oscarsson-Nagel, Walter Söllner, Endrias Asgedom, Øystein Trætten, Rune Voldsbekk
The Leading Edge - 1 April 2020
Marine vibrators have bespoke geophysical benefits that are yet to be harnessed because of robustness and efficiency issues. We have developed a new marine vibrator source technology that is efficient and stable. The source technology overcomes the historical problems of inefficiency and robustness by using folded surface technology and resonance frequency tuning. We show measured output examples that demonstrate that the folded surface concept combined with small displacements can provide the required output levels. Our source system consists of a low-frequency module covering 1–10 Hz and a high-frequency module covering 10–125 Hz. The source control system has shown high stability and precision and can handle harmonic distortion. With the aid of synthetic data examples, we demonstrate that seismic data acquired using marine vibrators in either intermittent or continuous mode can be processed. Finally, we demonstrate the environmental friendliness of the source in comparison to air gun-based sources.
Automation of marine seismic data processing
Author: Andrew Long, Tony Martin
The Leading Edge - 1 April 2020
Marine seismic data sets contain highly redundant information.Data analytics and machine learning-based solutions should provide opportunities to reduce turnaround and improve confidence levels in output data volumes. A proof-of-concept (POC) thrust regime example from Indonesia illustrates that parameter testing can almost be eliminated if existing project parameter data can be mined from a database. Where quality control (QC) is required for complex challenges such as noise removal, supervised classifiers are a platform that can enable rapid global quantitative decisions based on relevant data attributes, moving behind the subjective art of observational QC. Finally, many early processing steps depend on reasonable knowledge of the velocity model in addition to the explicit dependence of imaging steps. A POC Monte Carlo-based model building exercise in West Africa used an efficient tomographic platform to demonstrate that turnaround can be reduced from 90 days to only a few days, even when the starting model was significantly wrong. These examples illustrate that a lot is already within our reach, and the development of embedded feedback loops will improve the level of automation further, particularly if humans can learn to let the data speak for itself.
Improved presalt imaging using innovative model driven imaging technology
Author: Sriram Arasanipalai, Alejandro Valenciano Mavilio, Hermann Lebit
First Break - 2 March 2020
The authors outline the impact of advanced modelling and inversion technologies on seismic data reprocessing to support exploration and production objectives in a prolific presalt play offshore Brazil.
Fast Delivery of GeoStreamer X Multi-Azimuth Data
Author: Julien Oukili, Kai Fløistad
GEO - 1 March 2020
GeoStreamer X represents a faster and more efficient method to improve illumination
of complex targets.
Diving Deeper to Resolve the Challenges of the Barents Sea
Author: Sören Naumann, Rune Sakariassen
GEO - 3 February 2020
PGS’ Hammerfest Basin ultra-high-density high-resolution dataset is now available and will be extended further in 2020. Full integrity data includes open acreage and resolves the challenges in this complex area through an innovative combination of streamer setup and advanced imaging technologies.
What Does ‘Sparse’ Really Mean Anyway? Ocean Bottom Nodes, Towed Streamers and Imaging
Author: Andrew Long
Industry Insights - 2 January 2020
Towed streamer acquisition is drawing closer to the spatial sampling quality of the ‘ideal’ seafloor seismic survey, and the cost of seafloor seismic continues to attract considerable debate—particularly with respect to whether and how receiver spacing might be decreased to reduce cost (‘Sparse Ocean Bottom Nodes’ or ‘Sparse OBN’). The general topic of spatial sampling during marine seismic survey design is considered before some of the Least-Squares Migration (LSM) concepts introduced in theprevious Industry Insights article are revisited.
GeoStreamer X Pilot Successful - So What's Next
Author: Martin Widmaier
GEO - 19 December 2019
Completion of the GeoStreamer X pilot survey proves that PGS’ novel marine seismic strategy for upgraded acquisition in any geological regime is practical, efficient and within reach. The first GeoStreamer X data is scheduled before next Easter. Planning has begun for 2020 projects.