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.
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.
Least-Squares Migration: Status and Opportunities
Author: Andrew Long
Industry Insights - 5 December 2019
Least-Squares Migration (LSM) treats seismic imaging as an inverse problem, and can be implemented in a diverse range of ways. The common elements are that the output aims to provide an improved Pre-Stack Depth Migration (PSDM), and the velocity model is not updated during the process. When implemented using finite difference operators in an iterative workflow, LSM can be extended to imaging the full seismic wavefield. In addition to improving the amplitude and spatial wavenumber content of seismic images, LSM is now being explored as a solution to compensate for different acquisition geometries and/or shooting directions in 4D projects, or as a possible solution to deliberately reduce the acquisition cost and effort.
Optimizing performance of data processing
Author: Samuel Brown, Tony Martin
First Break - 1 December 2019
The authors describe the process of optimizing data throughput, to reduce turnaround and enable both full automation and interactivity of geophysical tasks in an architecture agnostic environment.
Application-Specific Integrated Circuits and Machine Learning
Author: Andrew Long
Industry Insights - 11 November 2019
An example of seismic data image processing of a real marine seismic dataset is used to demonstrate that Machine Learning has a future for seismic processing, but it also shows that huge training efforts are required for application to even modest input data sizes. As the applications of Machine Learning and Deep Neural Networks (DNNs) extend to ever-increasingly large and complex problems, the computational overheads will correspondingly become significant. Application-Specific Integrated Circuits will expectably become more common to address the vast computational challenges to training DNNs with modern 3D seismic data volumes, and will represent a new class of supercomputer with hundreds of PFLOPS of computing capacity available to solve each problem.
Redefining marine towed-streamer acquisition
Author: Martin Widmaier, David O’Dowd, Carine Roalkvam
First Break - 1 November 2019
The authors describe novel marine acquisition solutions addressing the need for accurate velocity models, high-resolution imaging, and reliable AVO.
Modern seismic data reveals potential for a deeper play in North Madura, East Java, Indonesia
Author: Maz Farouki, Andy Bromley, David Cavalin
APGCE - 29 October 2019
The East Java Basin is a prolific hydrocarbon province in Indonesia in which exploration plays have typically targeted the pinnacle reefs of the Oligocene-Miocene Kujung carbonates. Robust imaging of the deeper section however has historically been challenged due in part to the limited bandwidth of conventional seismic data. A further challenge arises from the imaging artifacts introduced at the overlying Wonocolo carbonate platform, where the slow velocities of deep channel incisions are in strong contrast with the fast carbonate velocity. Prestack depth migration can be used to address this issue, but requires a velocity model with sufficiently high spatial and temporal resolution to precisely capture such velocity variations. To this aim, Full Waveform Inversion is used in the velocity model building. Whereas legacy data in the basin has struggled to image deeper than the Kujung level, seismic acquisition and imaging methods are now providing data with greater bandwidth and deeper penetration of signal. In Madura, the deeper Eocene Ngimbang formation as well as basement are now much better resolved, opening up the potential play in the Ngimbang clastics.
Targeted vs. regional model building and imaging. A case study from offshore Sabah Malaysia
Author: David Cavalin, Yeou Mei Wong, Andy Bromley, Maz Farouki, Kola Agbebi
APGCE - 29 October 2019
MC3D velocity building and imaging using conventional tomography tools is regional in scope and fit for purpose for exploration. However, reprocessing and imaging using higher end applications will provide significant uplift provided the underlying seismic data is acquired and pre-processed to a standard that supports the hi-end applications. Detailed velocity, Q and anisotropic models were the key in this survey to properly image and de-risk a potential prospect. The information extracted from the migrated image but also from the high-resolution updated models can be later used for in-depth analyses including targeted structural interpretations, seismic inversion and quantitative studies.