Energized explorers

This year's Society of Exploration Geophysicists (SEG) convention was filled with an energy that it hasn't had in recent years.

This year's Society of Exploration Geophysicists (SEG) convention was filled with an energy that it hasn't had in recent years. Compared with last year's Dallas convention the meeting drew almost 50% additional attendance. Over 6,500 geophysicists from around the world gathered to share their insights into the world of seismic wiggles.

The exhibitors were pleased as well, reporting high quality contacts. This was most important since they brought plenty of new technology to the market. Much of that new technology focused on enhanced computer equipment for the interpreter. The latest innovation is the combination of clustered, Linux-driven CPUs with off-the-shelf graphics processing unit (GPU) cards from the world of computer gaming. This combination creates a fast visualization workstation that can handle larger data sets than ever before. Silicon Graphics displayed its new device that uses AMDs Opteron processors with ATI's GPUs. Sun answered with a similar system based on Intel's Itanium processors coupled with nVidia's GPUs.

Marine towed seismic acquisition technology has been stable for the past few years as the oil industry reduced its former high levels of activity. That activity level is beginning to jump again with the letting of several large contracts from ONGC, India's national oil company. The market for marine seismic acquisition services is tightening as the vessel fleet moves to higher utilization rates.

Of note is the growing interest in nodal systems for deepwater seismic acquisition. This approach uses 4C instrument packages (three oriented geophones combined with a hydrophone) dropped into deepwater in a widely spaced pattern. The shooting vessel then creates a dense air gun source pattern above and around the nodal seabed array. A signal from the vessel releases the nodes from their weighting element. This returns the node to the surface for collection, data retrieval, and redeployment.

New exploration technology CSEM (controlled source electro-magnetics) has entered the market in a strong way. This is also a nodal system, but it uses a deeply towed pulsed EM source to induce current in the seabed, which is then measured by the antennas spaced on the seabed. This technology detects the edge of hydrocarbon deposits where a change in resistivity occurs. At this SEG convention Schlumberger announced the purchase of AGO, which has gathered over 40 CSEM surveys over the past year. The technology is now commercial and is ready for refinement.

The next major market for seismic contractors is seismic monitoring of producing fields – production seismic. The 4D seismic market (time-lapse 3D) has been the province of traditional towed-array contractors. However, limits on streamer positioning often make it difficult for seismic processors and interpreters to separate signal from noise in 4D difference volumes.

WesternGeco's Q-marine system is gaining market traction for 4D surveys because of its ability to steer the streamer and match the surface locations of earlier surveys. Better positioning accuracy helps, but this location problem is solved by fixed-seabed sensor arrays.

The growing market acceptance of production seismic has encouraged the makers of competing towed-streamer and seabed-placed sensor technologies. These manufacturers are bringing new options to the market with more durable ocean bottom cable systems in conventional geophone, accelerometer, or light-fiber technologies.

10/15/04

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