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We present a workflow for 3D MAZ PSDM velocity modeling with tilted orthorhombic anisotropy. We focus on two aspects of depth-velocity modeling that are extremely important for seismic data from the NW Australian shelf: (1) high resolution adaptive seismic tomography to deal with strong velocity anomalies in complex geological settings and (2) practical workflow to build a tilted orthorhombic anisotropic PSDM velocity model in regions with complex velocity anomalies and strong horizontal and vertical anisotropy. We use real data from 4060 km2 3D MAZ PSDM Fortuna project located in the NW Australian shelf to illustrate presented workflow and its results.

It is well known that imaging of complex regions can be significantly improved with increased illumination in terms of offset and azimuth sampling. In this case study we illustrate how an existing large scale acquisition can be enriched by acquiring a second complementary survey in a targeted area. The second survey was acquired perpendicular to the first with additional offsets for maximum impact. The long offsets were enabled during a single acquisition pass by utilising a source only vessel positioned ahead of the main source and receiver vessel using simultaneous shooting. The blended data was separated using an annihilation filter approach. In this paper we illustrate the advantages this second survey has brought to the area though improvements in the FWI velocity model and enhanced illumination for the deep structures.

The Northern North Sea is a very active area for oil and gas exploration with several commercial discoveries made over the last few years. These include the Dugong discovery on the Tampen Spur and multiple discoveries in the Greater Fram area on the Horda Platform. CGG’s Northern Viking Graben (NVG) multi-client survey provides more than 44,000 sq km of coverage over this area.

GepoSpec Cameroon Terms of Reference for Proposals on free blocks

Preserve the geological and seismic detail in your static model during history matching, assess uncertainty and reduce time spent on manual model updates with this innovative and efficient ensemble-based multi-scale data-driven approach.

Deblending shallow water OBC data can be challenging. High blending fold, strong early arrivals, shear wave energy, and background noise all add to the complexity of the problem. Using an offshore Trinidad OBC survey, including dual and triple sources, we demonstrate the effectiveness of a specialized deblending strategy designed to tackle these challenges. This strategy combines the merits of two deblending techniques: cross-talk modeling and subtraction, and impulsive denoising. The process is guided by a blending-noise level map deterministically derived from actual shooting times. Test results on both P and Vz components confirm the effectiveness of this approach and raise the confidence level of the quality of deblended data.

A new OBN survey was acquired over the Shenzi field in the deep water GOM. The primary goal was to leverage recent advances in FWI to improve the velocity model with an expectation that the image would benefit from the full-azimuth, long offset OBN data as well. We discuss the project from feasibility/survey design study to OBN FWI update and its accuracy to the imaging uplift. As it turned out the best image for steep dips and faults was the FWI image and its impact on the seismic interpretation was significant.

Exploration activity in the Barents Sea has fluctuated considerably over the last 40 years, in line with the price of oil and general industry optimism. Today’s high level of activity focused on ongoing and planned field developments and production may spur further exploration as infrastructure is developed. Exploration efforts in the vicinity of the producing Snøhvit and Goliat fields have been successful and the ongoing development of the Johan Castberg Field is opening up new areas for nearfield exploration. An important tool in the search for additional resources is the recently processed Greater Castberg TopSeis survey, a CGG/TGS multi-client joint project.

At first glance, the Western Indian Ocean region may look like a barren oceanic crust with little potential, but there is tantalising evidence to suggest otherwise. CGG geoscientists have been sifting through the evidence to re-evaluate opportunities offshore East Africa and in the Western Indian Ocean. The discovery of world-class gas fields in the Rovuma Basin of Northern Mozambique and Southern Tanzania in the last two decades have shed light on the prospectivity of the East African Region and the Western India Ocean islands at large.