The focus of deepwater oil and natural gas production technology (in 2,000-3,000 m of water) now is on less costly and less risky methods for bringing on stream smaller satellite fields, about 100-300 million boe. These smaller fields will become the "bread and butter" of the deepwater industry, as discussed Nov. 17-21 in presentations at the 15th Deep Offshore Technology conference and exhibition in Marseilles, France.
The industry has drilled wells in more than 3,000 m of water, with the deepest exploration well drilled in 3,052 m of water in the Gulf of Mexico. The deepest producing field, on the other hand, is in only in 2,200 m of water, also in the gulf.
New technologies needed
Companies have found only a few giant fields in deepwater plays. The bulk of discoveries are the smaller hydrocarbon accumulations that require new concepts and technologies for economic development. To meet this challenge, the industry is pursuing such technologies as less-costly commodity-type production facilities supporting structures; lighter and less costly risers; better flow assurance; longer tie-backs; more seafloor and downhole monitoring and control; less-costly flowlines and umbilicals; and subsea metering, pumping, and processing.
Zaki Selim, president, well completions and productivity, for Schlumberger Oilfield Services, said fluid recovery would increase substantially from satellite fields with technologies that boost flow streams. He estimated that wells with long tie-backs currently have a potential for recovering only 75% of that of the expected recovery from similar land or platform wells.
Selim said the addition of technologies for boosting the flow could greatly increase recovery by reducing backpressure on wells to 50 psi from the 2,000 psi level now often encountered.
He also sees the need for subsea monitoring and control modules or seabed local area networks that could transfer data at 100-150 megabytes/ sec. With advanced monitoring and control, Selim said, companies no longer would have to design for the worst-case scenario.
Selling the associated gas produced with oil is another issue that the industry needs to resolve. No longer is it appropriate to flare gas, and reinjecting it into the subsurface formation is expensive.
Floating gas-to-liquids, LNG, and methanol facilities are some solutions discussed that may become economic as the industry makes advancements in these technologies.
Remaining potential
Charles Mattenet, executive vice-president, technology and operations division, for Total SA, estimated that the industry to date has found 60-70 billion boe in deepwater fields. Total expects the industry to find another 60-80 billion boe in the future.
Mike Rodgers, exploration and production portfolio and business development manager, PFC Energy, Washington, DC, said the major companies need to continue to look for these deepwater reserves because of the limited remaining potential of shallow- water prospects. He said nine companies own 75% of the discovered deepwater reserves and operate about 87% of them.
Rodgers estimated—excluding exploration—current deepwater field development costs are about $3.50/boe and that operating costs are also near this level.
