Abstract

Hurricanes Katrina and Rita packed a devastating one-two punch to the Shell Pipeline Company (SPLC) operated infrastructure in the Gulf of Mexico. Katrina, which hit the Louisiana/Mississippi coast on August 29th devastated the eastern gulf pipelines/facilities with high water, wind and seas. Rita, following three weeks later, struck the western Gulf and produced havoc due in large part to the number of drilling rigs which were broken loose from their moorings.

Both storms had different characteristics but the destruction can be placed into the following categories:

  • Flooded facilities with significant structural and electrical damage

  • Toppled platforms affecting boarding & departing Pipelines

  • Dented, cracked or separated pipelines caused by drill rigs dragging anchors

The Katrina and Rita storms were much different than Ivan (2004) with regards to pipeline movement due to mudslides. Ivan took a more easterly track than Katrina and its impact was very significant from a mudslide perspective. While there was some pipe movement associated with Katrina as it stretched into the eastern portion of the Mississippi River Delta, its impact due to slides was far less severe. This paper describes the actions following the storms and the subsequent repair activities, which were required to return the SPLC systems to operation.

In essence, the entire Gulf of Mexico pipeline infrastructure operated by SPLC was impacted by the two storms. Katrina concentrated her destructive force on facilities east of Fourchon while Rita took her toll on the facilities west of Fourchon. Repairs totaling more than $100 million are in progress. Repair work commenced immediately following the storms and will continue well into 2006.

Inspection of the Infrastructure

Immediately following the passage of Katrina, survey vessels with side scan sonar and magnetometer equipment were employed to begin surveying pipelines for damage, pipe movement, spans and exposures. Work concentrated in the eastern Gulf in the Nakika and Odyssey pipeline corridors in Mississippi Canyon and Main Pass blocks. Simultaneous to the side scan surveys, ROV and diver surveys were being conducted of risers, platform structures and areas where anchor drags were suspected.

Damage to the Mars and Ursa export lines was discovered due to a Mobile Offshore Drilling Unit (MODU) which dragged an anchor across all four lines. A remotely operated vehicle (ROV) spread was engaged to excavate the lines which were pushed down into the mud five feet and displaced 15-30 feet to the east of their as-built coordinates. A significant dent was discovered in the Ursa 20 ‘Gas line while a less severe dent was found in the Ursa 18’ Oil line. Excavation of the Mars lines revealed a through wall thickness crack in each line with seawater being pulled into the gas line.

While the damage from Katrina was being evaluated, Rita struck on a more westerly track. Once the storm passed, additional side scan survey equipment was placed on hire and surveys of the Brutus, Boxer and Amberjack pipeline systems conducted.

Keywords:
spoolpiece, connector, otc 18413, operation, crude oil, offshore pipeline, pipe end, katrina, drill rig, storm
Subjects:
Pipelines, Flowlines and Risers, Offshore pipelines
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2006. Offshore Technology Conference
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