Software and services key to seismic data processing

Paul Boughton

WesternGeco has introduced its ObliQ sliding-notch broadband acquisition and imaging technique, which enhances low-frequency content of marine seismic data without compromising high frequencies.
The ObliQ technique increases the penetration depth of seismic imaging and helps geoscientists extract rock properties from seismic data (Fig. 1). Optimised seismic bandwidth is achieved by combining variable streamer depth acquisition with a proprietary deghosting methodology and a newly developed broadband seismic source. This proprietary processing approach is applied early in the sequence, making the data suitable for both time- and depth-domain analysis.
“As the search for hydrocarbons moves to ever more challenging environments, the use of such advanced imaging technologies is becoming increasingly important for successful exploration programmes,” said Pennelope Ratcliffe, vice president, marine, WesternGeco. “The ObliQ technique provides broadband data for exploration purposes and complements the well-established WesternGeco DISCover broadband technology, which provides high-fidelity, full-offset broadband data using a proprietary dual-level tow.”
Enabled by the Q-Marine point receiver marine seismic system, the ObliQ technique can also be used with other WesternGeco technologies such as Coil Shooting and Dual-Coil Shooting full-azimuth acquisition to combine broad bandwidth with full-azimuth, long-offset acquisition. This combination is particularly important for imaging below complex structures such as subsalt and sub basalt. [Page Break]
New from RadExPro is RadExPro 2012.1, including a number of major upgrades. These include: higher-mode inversion is now available in the MASW module for more accurate Vs model. Users can now properly utilise all the modes seen in the dispersion image; new, much more convenient horizon picking (in hunt, auto fill, linear fill and eraser modes) in the screen display model; zero padding and inverse options are added to the trace editing module; a new module called comment allows users to add textual comments to processing flows and visually divide long flows into logical blocks; a number of bugs are fixed, including the file extension bug in the header import dialogue of the geometry spreadsheet and in some other places.
RadExPro also offers WellTomo crosswell travel-time seismic tomography software. This is designed for solving both direct and inverse tomography problems on either straight or curved rays. Curved ray tracing is implemented via solution of the eikonal equation.[Page Break]
Direct tomography problem solution consists of ray tracing from a set of sources to a set of receivers through a known velocity model. Inverse problem solution is a reconstruction of the velocity model, a system of linear equations is solved via an SVD-based algorithm.
For the direct problem solution, the input data are the coordinates (X, Z) of the source-receiver couples and a velocity model. A ray from a source to a receiver can be considered as eithrer straight or curved. The solution is a set of calculated travel times along each of the rays. As a result, the initial table with the coordinates of sources and receivers is supplemented by a column with the travel time values for each of the source-receiver couple.
The company also offers prime, next generation software for geology-driven 2D/3D seismic processing. This incorporates geological information already at the stage of data processing for reliable, geologically consistent and verifiable results.
Dolphin Group ASA has announced that through its subsidiary Dolphin Geophysical (US) the company has purchased the entire stock of Open Geophysical (OGI).
OGI develops and sells seismic processing software and has an existing client base including both major oil companies and seismic contractors. The software is purpose built for modern computer architectures and has an industry leading graphical user interface. It thus provides users with an efficient, cost effective and easy to use seismic processing platform. The newly developed software is already being used on the Polar Duchess for real time quality control of acquired data with impressive performance and in Dolphin's new processing centre established in London.[Page Break]
All Dolphin vessels will be upgraded to the OGI software over the coming months. It will be used for on-board fast track, proprietary processing on the Duchess in the near future and to produce a high-end, fast track product on all future multi-client projects.
R Gareth Williams, chief geophysicist of Dolphin said: "We are extremely excited to be investing in OGI and to be using the Open CPS software for both our on board and onshore, marine processing package. This is a major step towards developing our processing and multi-client services and hence capturing the full value chain in those businesses. We carefully reviewed all the available software platforms and this is a rare opportunity to work with a system designed completely in the 21st century. In addition, we see significant opportunities to support and grow the existing software sales business of OGI and are fully committed to supporting their current customers."
Roland Gunther and Eric Foley, co-founders of OGI stated: “Working with Dolphin will provide us with the opportunity and financial strength to increase the pace of development of our software and to benefit from working closely with an experienced team. We look forward to providing increased levels of support and technology to our current and future customers who are working with both land and marine seismic data. We expect OGI to benefit from the increased global exposure for the software via Dolphin's multi-client and proprietary projects"
For its part, Geokinetics has been providing seismic data processing services to the oil and gas E&P industry for over 30 years. With processing centres in the US and UK, and client-site capabilities, it offers proprietary, flexible, state-of-the-art technologies to solve any processing issue, any size survey, and any acquisition configuration.
Geokinetics is the pioneer and industry leader in AVO and true amplitude techniques and specialises in well-to-seismic calibrated processing. Amplitude integrity and well-driven parameterisation are fundamental aspects of all of its processing services:
In providing all of its services, the company emphasises experience and expertise, capability, reliability and quality. Its objective is to fully meet the requirements of clients through technical excellence and business efficiency, while maintaining a firm commitment to the highest standards of quality and service (Fig. 2).[Page Break]
In terms of signal process and time imaging, innovative processing solutions are a company speciality. “Our proprietary software and highly experienced staff set the industry standard for quality, speed and personalised service,” it says. Since 1999 Geokinetics has been providing depth imaging services to the oil and gas industry. Its depth imaging team has completed projects in all parts of the world including the Gulf of Mexico, Latin America and West Africa. When it comes to multicomponent processing, the company has capabilities for 2C (or PZ summation) and 4C marine OBC processing and 3C and 9C land processing. Finally, its AVO analysis relies on the latest anisotropic technology to capture the lithologic response that conventional AVO processing disregards, even in 3D.[Page Break]

Dolphin lands African deal
Dolphin Geophysical has signed a further agreement with authorities in Africa to acquire additional 2D multi-client survey over recently designated deep-water blocks soon to be offered to industry for licensing.
These new long-offset 2D data will form part of the ongoing North West Africa Atlantic margin (NWAAM) project that commenced last year. Data will be processed in the UK by Dolphin's partner in the project, TGS, who will also integrate these new lines with the regional interpretation work already in progress. Following the completion of this, road-show seminars are being scheduled in London and Houston later this summer when representatives from each of the governments involved will be present to promote available acreage as well as hold private discussions with interested companies.
Acquisition of these new AGC lines is already underway and scheduled for completion shortly. These additional data of about 1800 km will make the total for the NWAAM project to date around 17,000 km - from Northern Senegal to Southern Guinea Conakry.
Dolphin Geophysical has also signed a further agreement with the government of Mauritania to acquire additional 2D multi-client survey over certain offshore areas including designated deep-water blocks. These additional data of about 9000 km will further increase the total for the NWAAM project to around 26,000 km from Northern Mauritania to Southern Guinea Conakry, providing the only continuous, conformable well-tie regional dataset in this under explored but potentially prospective area - possibly with similar geological plays to those already discovered in Sierra Leone, Liberia and Ghana.

Fig. 1. The ObliQ technique increases the penetration depth of seismic imaging and helps geoscientists extract rock properties from seismic data.
Fig. 2. Geokinetics is focused on quality and service, through technical excellence and business efficiency

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