Seismic package has 'extreme' channel count point-receiver

Paul Boughton
Jeremy Cresswell looks at the pick of what's new on the seismic technologies block.

Schlumberger unit WesternGeco has launched an integrated point-receiver land acquisition and processing system named UniQ. The group says this new package combines 'extreme' channel count point-receiver technology with support for advanced simultaneous source techniques. It is intended to deliver 'ultra-fast productivity for exploration surveys' and builds on the fidelity provided by Western's broad bandwidth Geophone Accelerometer (GAC) sensor,

The result is that UniQ can support up to 150,000 live channels at a 2 millisecond sample interval. With the seismic system's continuous recording capabilities and support for simultaneous source techniques, this means the package can be used for dense reservoir characterisation projects, as well as for sparse fast-moving exploration surveys.

Western says too that UniQ will provide significant advantages in challenging noise environments and in areas with complex geologies. Not only that, it is claimed to be as effective in desert environments as the Arctic, where it has been field trialled.

The field planning software, source and recording control systems and camp data-processing facilities are all designed to work in an integrated manner, to enable efficient equipment layout and optimised data handling while also reducing the time from shot to processed deliverable. In other words, it gets results that can be rapidly applied, so enabling on the hoof changes to survey campaigns.

WesterGeco has also been busy on the marine seismic front, having also developed and introduced 'Coil Shooting, full-azimuth (FAZ)' single-vessel acquisition. This is a technique for acquiring marine seismic data while following a circular path.

Multi- (MAZ) and wide-azimuth (WAZ) are proven, successful methods of seismic acquisition for complex geological areas.

The drawback is that WAZ surveys involve a number of vessels - typically a flotilla of three or four - parallel offset from each other, some towing sources only, others towing sources and streamers.

The problem then is that it takes a lot of time to move from one survey line to the next, and time costs money.

It was while carrying out a project in the Gulf of Mexico that WesternGeco experimented with acquiring usable data during this line change period. Then it was realised that high-quality full-azimuth recordings could be achieved by acquiring data with a single vessel traveling in a series of circles, thereby removing the need for the multiple vessels (and additional streamers) required by today's WAZ designs.

Coil Shooting was field tested in the Gulf of Mexico and the Black Sea, and produced positively dramatic results that clearly show the potential for applying the technique on a global scale.

WesternGeco claims that steering the vessel, streamers, and sources in a corkscrew fashion delivers a greater range of azimuths and offsets (including near offsets) than parallel WAZ geometries and uses only a single vessel. Moreover, coil shooting offers a scaleable solution that can be applied equally well to large and small projects without the overhead of mobilising several vessels. The company says controlling the streamers is effectively achieved by deploying its proprietary Q-Fin steering system.

Staying afloat, across at ION Geophysical in Houston, this company's Concept Systems software group has just signed a five-year agreement with Petroleum Geo-Services (PGS) for the progressive upgrading of all its existing 2D and 3D towed streamer vessels Orca command and control. All new-build vessels will be similarly fitted.

Orca - the predecessor system was known as Spectra - is described as the first of a new generation of integrated command and control systems designed to harness the complex data workflows found onboard modern seismic vessels. It apparently takes account of the latest hardware, software, and positioning technologies and it manages navigation and seismic data workflows for vessel operators, enabling them to operate more safely and efficiently during complex survey operations while delivering processing-ready data to clients.

Announcing the deal on 1st December 2008, Rune Eng, PGS Marine Acquisition group president, said the company had a long standing relationship with Concept Systems and that, as towed streamer surveys have become increasingly complex, it was recognised that new functionality was needed to more efficiently carry out the most technically advanced, multi-vessel marine acquisition campaigns, including 4D and HD3D (high definition) surveys.

Next stop is the seafloor, where Quasar Geophysical Technologies chose the Society of Exploration Geophysicists (SEG) annual meeting on 11th November 2008 to debut a new type of ocean bottom electromagnetic (EM) receiver. The purpose of QMax EM3 is to 'unlock the potential of EM surveys with improved operational efficiency, safety, and comprehensive data'.

Quasar said this new generation receiver would not require long electric-field arms, resulting in improved safety and logistics. Moreover, it had been fitted with a 'hot-swappable' battery/data module for easy, fast, on-deck turnarounds. Further, the company said that standard vertical magnetic-field and vertical electric-field sensors provide more robust data sets, and that its capacitive electrodes increase reliability and do not require special handling.

Staying with EM, and briefly referred to in the CSEM feature, Norwegian company EMGS has successfully launched what it claims to be the world's first fully integrated EM system.

Clearplay, which has started to lay down a track record operationally, was launched at the 2008 European Association of Geoscientists and Engineers (EAGE) annual conference and exhibition.

Playing on the theme that finding oil and gas resources beneath the oceans is getting tougher, EMGS said Clearplay can provide 'seamless, end-to-end electromagnetic services and products'.

Indeed, Clearplay comprises three main elements: Clearplay Find, Clearplay Test, and Clearplay Evaluate, each of which is aimed at improving exploration efficiency and performance, reducing finding costs, and reducing risk.

Integrating Clearplay with the traditional exploration workflow is reckoned to enable a clearer and more complete understanding of the subsurface and thereby better decisions reached more quickly, and the right resources applied in the right place to maximise and accelerate return.

Though launched mid 2008, the full commercial release of Clearplay was not implemented until Q4.

This tour started on land and we wrap it by returning to terra firma and Ascend Geo's successfully completed field demonstrations of its cable-free land seismic acquisition system at a test site near Devine, Texas.

Ascend's Ultra G5 system was put through its paces in a full-cycle data recording operation mid-2008 with real-time cable-free system deployment and retrieval, live recording, data download and synchronisation, and display of the acquired trace data.