Conoco- Future Tension Leg Platforms (TLPs)

July 5th, 1996- HOUSTON Texas -- Future Tension Leg Platforms (TLPs), capable of working in waters that make today's 3,000—foot depths in frontier areas seem shallow by comparison, will have to use new technologies to meet the challenge. And, TLPs may not always be the development and production system of choice.

That's the forecast from Conoco, the company that proved TLP technology, and has built and installed half of the existing TLPs in the world.

"TLPs have to meet the changing economic, environmental, engineering and logistical criteria of operating into 3,000—foot and deeper water depths, " says David W. Branch, Conoco vice president for exploration and production technology. "TLP technology was developed to overcome the unacceptable weight and costs of fixed, all—steel platforms for operations in water depths greater than 1,000 1,500 feet of water. But TLP weights that are compatible with the water depths we are in today will be unacceptable in the water depths we're looking at five to ten years down the road, he added.

Referring to Conoco's use of light—weight materials such as aggregate concrete and titanium risers in the Heidrun TLP, Branch said, t 'TLPs are on a diet, but even more exotic materials like carbon fibers and DuPont's Kevlar will be needed to get the weights down to acceptable levels for very Deepwater applications."

 Future Deepwater Technologies

Branch said many companies were already looking at how composites could be used in TLP construction. He cited the efforts of Conoco, its parent company DuPont and Norway's Kvaerner who are jointly pursuing identification and development of T LP components that can be made from composite materials.

Other weight reductions could be achieved by eliminating or reducing some materials and equipment that are necessary with today's technology.

"By using titanium in Heidrun's drilling risers, we achieved a significant weight reduction. Just think of the advantage that could be realized if we could eliminate most of the risers, he said.

Conoco is actively pursuing the development of "riser less" drilling for Deepwater operations. In additional to saving weight, Branch said the concept offers explorers other benefits. According to Branch, economics will determine the future utilization of TLPs in Deepwater oil and gas operations.

"The industry's experience in building TLPs has helped bring their construction cost down and there aren't many radically new technologies on the drawing board that seem to offer enough cost reduction to warrant the cost of prototype development, Branch said. But, TLP technology and adaptations of TLP technology -- must be able to compete economically with other existing systems that are equally suitable to changes in the industry's approach to Deepwater operations, he added.

Future Deepwater Technologies

An example of a different approach for new field development being used by the industry is "phased development, where a field is incrementally developed.

"Taking a phased approach to reservoir development instead of the traditional 'let's develop it all at once' approach mitigates a number of risks, Branch said. "It reduces cash exposure by allowing production to start sooner and lowers the investment in appraisal wells. Additionally, it gives you far more options down the road, depending on whether reservoir characteristics and production rates meet expectations.”

Branch said TLP technology would have to compete with other production systems like subsea completions and Floating Production Storage Vessels and semi—submersible's, which are economically and technologically compatible with the phased approach concept.

But, Branch emphasized that industry's future development of deepwater reserves would depend on more than technology.

“We have, or can develop new technologies necessary to get us were we want to go. But, if project economics do not justify the cost of deepwater exploration, and if we can't continue to find the large, high—performance reservoirs, we won't need the TLPs -- or the new technologies -- because we won't be there.”

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5/7/96