Comments: Storm on the Horizon

Abstract

It is already a very active hurricane season in the Atlantic. Seven tropical storms, including two major hurricanes, occurred in June and July. That is the most major Atlantic storms this early in the hurricane “season”—which runs from June to November—since 1851. The U.S. Natl. Weather Service now predicts 18–21 tropical storms this year, with nine to 11 becoming hurricanes, including five to seven major hurricanes. That would be one of the most active Atlantic hurricane seasons on record and the ninth above-normal Atlantic hurricane season in the past 11 years. With global oil supplies tight and the oil market seemingly on edge, any storm that disrupts even short-term production would cause prices to spike. And with deepwater production from the Gulf of Mexico (GOM) becoming a major source of supply for the U.S., and Mexico also venturing farther out into the gulf, the issue of hurricanes and how to withstand them has become a major topic of concern for producers. What really got the industry’s attention was last September’s Hurricane Ivan in the GOM. That storm seriously damaged 31 platforms, destroyed several more, and disrupted more than 10% of GOM output for 4 months. It shut down most of the production in the eastern portion of the gulf and damaged pipelines and platforms along a wide swath, but there was no loss of life, and no major pollution occurred. High waves destroyed six platforms, and a mudslide destroyed another. Then in July, Hurricane Dennis affected BP’s Thunder Horse platform in the GOM, the world’s largest semisubmersible platform. After evacuating from the storm, workers returned to find the platform listing at a 30-degree angle, although it has since been righted. Dennis was classified as a strong Category 3 storm, with winds of 120 miles/hr. Thunder Horse, designed to process up to 250,000 BOPD and 200 MMcf/D of gas, was expected to come on line later this year. That timing is now in doubt. It is the largest field in the U.S. GOM, with recoverable reserves of 1 billion bbl. During a panel session at this year’s Offshore Technology Conference, representatives from the U.S. Minerals Management Service (MMS) said it was particularly concerned about the anchoring of drilling rigs on production platforms, mobile rigs that had broken off mooring, and the pipeline damage. The MMS recently authorized six studies that will examine the impact that Hurricane Ivan had on oil and gas structures and will recommend how to make offshore pipelines and platforms more resistant to storm damage. Included in the reports will be an assessment of the effectiveness of current design standards and pollution-prevention measures. MMS awarded more than U.S. $600,000 to Texas A&M U., Offshore Risk and Technology Consulting, Det Norske Veritas, Energo Engineering, and William Lettis and Assocs. to study, among other things, hardware on offshore floating platforms, mooring standards, pipeline damage, and the occurrence and effect of mudflows and mudslides. The studies are expected to be completed over the next 14 months. Some changes already have been made after experiences with last year’s and this year’s storms. Companies that have platforms shut down because of storms now must make daily production-loss reports to the MMS. Rigs and platforms now must be equipped with glob-al positioning devices so that they can be quickly recovered after a hurricane. And the industry is now securing bolting mechanisms and clamps on drilling units before evacuating rigs. Of course, hurricanes in the Atlantic and their impact on the industry are nothing new. A hurricane crippled Mexico’s production from the Bay of Campeche in the early 1990s. SPE’s eLibrary has technical papers on hurricane case studies and modeling going back 3 decades. The industry’s first experience with hurricanes in the gulf occurred in the 1930s, when a trestle that extended a mile from shore south of Port Arthur, Texas, with drilling rigs at the end of the line was destroyed by a small hurricane. That type of structure had worked well for offshore drilling in California, but it quickly became clear that it would not work in the GOM. From then on, engineers have struggled with building offshore structures that could withstand the powerful winds and waves spawned by fierce storms.