Research Breakthrough: New Streamers Successfully Debuted In Gulf Of Mexice

Western Atlas Inc. announced the successful sea trials in the Gulf of Mexico of a new generation of streamers. The company's Houston-based Western Geophysi- cal division deployed a 24,934-ft. (7,600-m) streamer in a 2-D pro duction mode, a world record for seismic vessels, and is currently acquiring 3-D data in the Gulf of Mexico using a single vessel towing four 19,684-ft. (6,000-m) streamers.

The new streamers, which are reportedly much slimmer than the previous generation, will also enable the company to add more streamer capacity to its fleet of multi-array vessels at very low cost. Currently, Western Geophysical is preparing to re-rig vessels for up to 10 streamers.

Richard White, president of Western Geophysical, said, "This new streamer technology, the WG- 24A, is based on our original WG- 24, the first marine streamer to acquire 24-bit data, which greatly increased signal range and data quality. Now, we have been able to reduce the diameter of the streamer and build it in a modular form.

"These design advances dramatically reduce weight and drag in the water, allowing us to adjust the length to the geologic and customer requirements, and especially to increase vessel capacity at a very low incremental investment." The new modular, slim streamer has shown excellent noise characteristics, a prerequisite for acquiring high-quality seismic data. Western Geophysical expects a number of competitive advantages from the new product.

In deepwater and subsalt surveys, the longer streamers will enable the company to achieve "long offsets" with a single ship, eliminating the necessity to use a separate shooting boat.

Western Geophysical has tested a 28,871-ft. (8,800-m) single cable and plans to deploy up to 32,808-ft. (10,000-m) streamers for this application in the near future. In a multiple-streamer market such as the North Sea, more streamers can be added to the company's vessels without the cost of major reconstruction of boats and with usage of the existing propulsion system. The modular construction also reportedly allows for easy maintenance.

"This design secures our investment far into the future," said Mr.

White. "With all of the control electronics in the electronic modules, we can quickly respond to any changes in cable technology, but continue to utilize our electronic modules." The WG-24 and WG-24A systems were designed by Western Geophysical and are now being manufactured by Input/Output Inc.

Western Geophysical currently operates eight vessels that can be upgraded with up to 10 streamers, and an additional eight vessels for special-purpose surveys, such as very long offset shoots and shallow- water data acquisition.

"The objective of our R&D and investment efforts is to deliver superior seismic surveys with a faster turnaround time and constantly reduce costs to our customers," Mr. White said. "Our new marine streamer, ocean bottom cable technology and recent investment into a new generation of supercomputers are the latest examples of this ongoing commitment."