March 2001 Vol. 222 No. 3  Drilling

Robert E. Snyder,  Editor

Offshore recovery; U.S. needs Sale 181

In Global Marine’s mid-January annual review and forecast, the company said its Summary of Current Offshore Rig Economics (SCORE) worldwide indicator increased 50% in December, compared to December 1999. SCORE compares the profitability of current mobile offshore rig rates to those of the 1980 – ‘81 peak, when speculative new rig construction was common. However, the actual values of 42% for the U.S. Gulf and 37% worldwide don’t indicate much newbuild iron cutting in the near future.

Global says there are 567 mobile offshore rigs competing worldwide. Of these, 466 are currently under contract, leaving 101 idle. And 25 of the idle rigs are currently unavailable; these are in shipyards for upgrades, inspections or repairs, but can be expected to enter the market before the worldwide SCORE reaches 100%.

Although each contractor will commit to construction under its own investment guidelines, many would expect to earn a dayrate of at least $95,000 a day for a minimum of eight years to justify spec building of a typical 350-ft, moderate-environment jackup costing $110 million. Current dayrates range from $50,000 to $60,000 for a 350-ft, moderate-environment jackup in the U.S. Gulf, and $50,000 to $90,000 for a third-generation semi in the North Sea, Global noted.

In a 1992 study, Global found that the retirement rate for semis accelerated rapidly after 18 years – five out of six are retired before reaching 27 years. Jackups last longer; retirement rates accelerate after 19 years, and five out of six are retired before 33 years. It takes two to three years from design through commissioning to build a new mobile offshore rig.

IADC supports Sale 181. In testimony at a hearing in Pensacola, Florida, on proposed Eastern Gulf of Mexico OCS Lease Sale 181, Paul Kelly, Rowan Companies, and Chairman, IADC Government Affairs Committee, emphasized the importance of the Gulf of Mexico in meeting increased U.S. gas demand. The hearing by the U.S. Minerals Management Service was held in early January. Sale 181 is scheduled for December 2001.

Kelly cited the forecast of a 1999 study by the National Petroleum Council indicating that U.S. gas demand will grow from the present 22 Tcf/yr, to as much as 32 Tcf/yr by 2015. And as much as a third of that increase must come from the U.S. Gulf.

"On the Shelf, producers are having a hard time just staying even," Kelly said. "That’s why we need deep water. More than half of what we need (from the GOM) hasn’t been discovered yet. It will be a challenge to meet rising gas demand from the Gulf. We can’t bet everything on the Central and Western Gulf offshore Louisiana and Texas."

Sale 181 will be the 11th held in the Eastern Gulf, and the first Eastern Gulf sale proposed since 1988. And it includes a small portion of the EGOM Planning Area, 15 mi or more due south of the coast of Alabama and, as requested by the State of Florida,100 mi due south of the Florida Panhandle. The sale area consists of 1,033 lease tracts covering 5.9 million acres.

Thirty-nine tracts in the sale area are now leased; Unocal began the first production in the EGOM Planning Area in early 1999. But in June 1998, President Clinton withdrew from leasing, until 2012, all of the EGOM outside the Sale 181 area.

Kelly also testified at a hearing on the Draft EIS for the proposed sale. As in previous hearings, many residents turned out to oppose the sale. And on January 23, Florida’s Governor Jeb Bush opposed the sale, saying in a letter to the DOI, "I respectfully request that you uphold Florida’s ongoing commitment to protecting the GOM’s marine environment by canceling the proposed Lease Sale 181."

In other IADC action, it notes that recent updates to its Deepwater Well Control Guidelines are now available as a supplement that can be easily added to the Guidelines document. New topics cover: unplanned disconnects in deepwater drilling; riser margin overview; external pressure loading of BOP equipment; and volumetric rating of subsea accumulator bottles. For more information on ordering, contact: IADC publications; Tel: 1 281 578 7171, ext. 215; or publications@iadc.org.

And, IADC says its Drilling Manual is now available on CD-ROM. The electronic version includes 1,252 pages and 1,700 illustrations; it can be used on any PC or your company’s network. Use the above number for ordering.

Lasers can cut oil blowouts. A laser-beam technique which counters oil drilling blowouts has been perfected by scientists Professor Alan Lettington and Dr. David Waterman at Reading University, England.

Explaining the technique, Waterman said, "When searching for oil, the drill bit sometimes approaches a pocket of natural gas trapped between layers of porous rock. If water alone is used to lubricate the bit, the pressure is relieved on piercing the gas. Bubbles of gas form in the slurry around the bit, in a similar way that bubbles form when the cap is removed from a bottle of carbonated drink. But when drilling for oil, such gas can ignite due to the red-hot friction of the bit, causing a dangerous and costly explosion."

A laser beam which gives operators on the surface time to take remedial action before an explosion occurs can now detect these tell-tale bubbles. This is achieved by increasing density of the lubricant used (to keep pressure at the bit as high as possible) to contain the pocket of gas, preventing a potentially catastrophic blowout.

The technique illuminates the slurry around the bit with sheets of laser beams. As the bubbles pass through the light, they show up like dust passing through a cinema projection beam. Their size and speed can be determined by the time interval between the bubbles lighting up adjacent sheets of light.

Also, the beam measures the amount by which the light bends when passing through the bubbles. In this way, they can be discriminated from cuttings in the slurry, improving the technique’s reliability. The technique is expected to come into commercial use within the next two years. Dr. Waterman can be contacted at: Tel: 44 118 931 8005; Fax: 44 118 931 8924; Email: information@reading.ac.uk.