We provide a unique range of technologies, services and equipment designed to deliver geoscience solutions right across the Exploration & Production life cycle.
View all our multi-client data in your area. Explore the new and improved CGG GeoStore interactive map.
Get to know the mission, vision and values that drives us.
Learn how CGG's leaders and governance allow for successful operations.
Operating safely and with integrity in order to deliver sustainable performance.
CGG recognizes the 10 UNGC principles and publishes annually its communication on progress.
You’ll discover a place where you’ll continue to grow as you work with other talented professionals around the world.
Explore an extraordinary opportunity to help create the future solutions of geoscience challenges.
Our range of geoscience experience is unparalleled and leads us to invent and perfect technology and techniques unlike any other.
GeoTraining brings together the full breadth of CGG’s skill development programs to provide the E&P industry with comprehensive geoscience workforce learning path programs.
Expert, independent advice on the most appropriate satellite imagery (optical, radar) and elevation data products.
The benchmark for petrophysics, rock physics, facies analysis and statistical mineralogy. Collaborative multi-well log analysis made easy for better drilling decisions.
CGG monitors stability of the source signature in the changing sea environment via shot-by-shot far-field signature estimation from near-field recordings using a proprietary inversion method. This delivers improved on board quality control with source stability and status monitoring, It provides improved reliability and confidence in data quality from near real-time QC that is both conventional and BroadSource™ compliant. The derived signatures can be validated by mid-field and far-field measurements. This delivers accurate far-field signatures to processing for better designature and ultimately a better image.
Real-time far-field reconstruction from near-field hydrophone recordings enables monitoring of shot-to-shot source signature stability.
The source signature is monitored on a shot-by-shot basis in real time via far-field signature estimation from near-field hydrophone recordings using a proprietary inversion method to deliver:
Stack comparisons of designature using a modelled signature versus one estimated from NFH.
A source array is typically composed of twenty to forty airguns of different volumes, roped to an alignment of floats and submerged at depths between 6 and 10 m. This flexible configuration is towed by the seismic vessel in a changing sea environment, making the array a complex and dynamic system. Small changes in the relative depths of the different parts of the array can cause significant changes in the way the bubbles interact and therefore the accuracy of a modelled rather than a measured signature. Actual source signals resulting from these coupled systems can vary from the theoretical in both the time (from shot-to-shot) and observation directions. Signal instability, can be caused by gun failures (dropouts and delays) and scattering from the changing rough sea surface. CGG uses various indicators for onboard monitoring of the source far-field signal from shot to shot.
The far-field source signal of the airgun array (far-field referring to a distance from the array where the signal appears as if it is emitted from a point source) is difficult to measure, but can be estimated from the near-field recordings (hydrophones placed one meter above each airgun). We use a proprietary inversion method which takes the non-spherical pressure propagation into account, offering an improvement on Ziolkowski’s notional method. It is conventional- and BroadSource™- compliant.
Amplitude variations are monitored using the average amplitude and maximum amplitude deviations between the current and a reference within the bandwidth. The reference signature may be fixed or formed from a stack of either all shot signatures from a navigation line, or over a sliding window about the current shot. Large deviations indicate possible gun failures.
The lateral directivity of the source signal depends on actual array geometry, so directivity monitoring requires an accurate knowledge of each airgun position. The airgun positioning accuracy of the GPS measurements from antennae on the gun floats (2-3m) is insufficient for monitoring the source directivity, so we use inversion of the source array geometry based on joint near-field recordings from alternate starboard and portside sources.
When one source is firing, the near-field recordings from the non-firing source (mid-field recordings) are analyzed to locate the positions of both arrays by joint inversion with the near field hydrophone measurements. This method allows reconstruction of the actual airgun positions with an accuracy of up to 0.2 m. The radiation pattern of the far-field signal describes its amplitude directivity as a function of frequency and observation direction from the source position. This enables the derivation of an accurate 3D signature for use in 3D designature.
The estimation of the bubbles and low frequencies of the signature obtained from near-field hydrophone recordings, is much more accurate than that obtained from modelled response. This delivers more accurate debubbling and more stable low frequencies after designature, especially 3D designature, and deghosting.
Contact us by opening an online inquiry.
EITHER... search our portfolio of innovative solutions:
OR... browse our alphabetical directory of geoscience products and services:
Explore CGG's impressive library of journal and magazine articles.
Read more about Quietsea™ marine seismic equipment and its ecodesign.