Texaco evaluating options for Petronius continuation

The J. Ray McDermott DB-50 heavy lift vessel shown here lowering the topsides for the Neptune Spar, experienced a cable failure on the Petronius lift.

As it stands, Texaco and its partners face a variety of unattractive options concerning the now-delayed $500 million Petronius project. The South topside module of the 2,000 ft compliant tower is damaged and resting in the mud of the sea bottom.

While it no doubt has some salvage value, the $70 million unit weighs in at 3,600 tons. Some salvage experts believe the position of the module and the depth of the water could increase this lifting weight by a factor of 1.5 (5,400 tons). At the same time, industry sources say the lead time for building a new module would be at least 18 months.

The first module was built over a year and a half, but the downturn in the market coupled with the experience Gulf Island gained in constructing the first module would most likely make things move faster the second time around. Gulf Island Fabricators declined to make a statement about the project.

In the meantime, Petronius is missing its first quarter 1999 target for first oil and has a half-billion platform eccentrically loaded in 2,000 ft of water. While the loss of the module is covered by insurance, it is unclear if the costs incurred by this delay will also be covered. The North module, ironically the heavier of the two, at near 4,000 tons, was successfully installed at the end of November just before the accident.

This eccentric loading throws the whole structure off center, and - in the words of one engineer - changes the stress loads on the entire tower. Officials with Texaco say there is no real concern about the uneven loading. The company plans to shield the North module against winter storms and may install some counterweight, but for the time being, there is no real concern about problems related to this uneven weight distribution. One spokesman said if the tower is off-center it is not visible from the surface.

What went wrong

With the passage of time, more information has become available on exactly what happened on the night of December 3 in Viosca Knoll 786. It appears that the DB-50 had the South module suspended in a fixed lift for at least 5 minutes when one of the two 18,000-ft, 2.25-in. diameter working cables broke. As the cable unspooled from the 32 sheaths in the top and bottom blocks, workers who had gathered at the stern began running from the area. The module apparently swung into the stern of the derrick barge before breaking loose and falling into the sea, taking the hook, block, and cable with it.

The lift contractor, J. Ray McDermott, is facing its own set of problems as a result of the accident. With the loss of the hook and block, the DB-50 is out of commission and sitting in drydock at the Atlantic Marine yard in Mobile, Alabama. Fortunately, Petronius was the vessel's last big lift of the year and it is scheduled to convert to pipelay mode for a project beginning January, 1999.

Sources at J. Ray McDermott said the vessel will be ready for this project. This means it will need a new crane, but not as substantial a boom as required for heavy lift work. The vessel was reportedly damaged when the 2.25-in. working cable broke and unsheathed. The only injury resulting from the incident was the crane operator. When the module swung into the vessel, it crushed the crane and the cab where the operator was sitting, pinning him in his seat and breaking his leg. The operator reportedly was able to leave the cab under his own power.

The module was a fixed lift and the second of the week for the DB-50. The cable that broke was reportedly installed in 1995. It is not unusual for the same cable to be used for several years. There were earlier reports that a replacement cable was nearby, but that has been discounted. As the cable unsheathed and dropped with the module to the sea floor, some sources said the hook and block plowed through the module and were buried up to 20 feet in the mud. Texaco said ROV footage disproves this.

The block and hook actually came to rest off to one side of the module. While sources refer to the $70 million module as "scrap," the hook and block might be worth fishing for. According to sources at J. Ray McDermott at press time, a decision had not been made on recovering the block or taking a sample of cable for test purposes.

Replacement

The lead time on a block replacement is over a year, with the additional forging and testing required, and there is a substantial dollar value attached to this item. It is impossible at this time to accurately determine what caused the cable to snap. All of the 18,000 ft of working line lies on the seafloor. It is likely a sample of this line could be retrieved via ROV and returned to shore for testing. While the cable was not particularly old, sources say there is no clear evidence of the exact shelf-life of this material.

Texaco was fortunate in two respects. The lift took place over 1,400 ft from the tower itself, and did not place the tower at risk. Also, the lift took place south of

the tower, while the two preinstalled pipelines run to the north. This means there was no damage to either the tower or the pipelines.

Earlier news reports also speculated that the Minerals Management Service might require Texaco to salvage the module immediately. According to MMS Public Affairs Officer Barney Congdon, the regulations would not require removal of the module until production ceases on Petronius. This could be more than 20 years in the future. In addition, because the field lies in deepwater, there is a possibility it may not have to be removed at all. Congdon said discussions are ongoing with Texaco on this subject and no decision has yet been made. While the DB-50 obviously was covered by insurance, as was the module, the loss in revenues during the delay in first oil may be substantial for Texaco and its partner Marathon. In addition to causing substantial damage to the DB-50, the falling module reportedly smashed a sizeable hole in the tow barge, MWB-403.

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