Dredger strikes subsea gas pipeline in Gulf of Mexico, El Paso production platform shut in

Rob Almeida
Total Views: 38
April 1, 2011

Image (c) Lisa Haug

CAMERON, LA – The Dredge Bayport, operated by Manson Gulf, LLC, was dredging in the Calcissieu Ship Channel on 30 March when they struck a 12″ condensate and natural gas pipeline.  Damage to the pipeline resulted in a highly flammable “fountain” of gas and condensate erupting from the surface of the ocean.

The following is the press release from Marine Safety Unit Lake Charles:

Incident Summary: At 2030 on 30 Mar, while conducting dredging operations in the Calcasieu Ship Channel, the dredge BAYPORT struck a sub-soil 12″ gas/condensate oil pipeline causing a breach in the line and a visible
“fountain” of natural gas & condensate at the water surface.

Location: 29-37-54N, 093-19-20W; near buoy #28 in the Calcasieu Ship Channel, approx 10 miles south of Cameron jetties.

MSU LC contacted El Paso Energy platform in West Cameron Block 62 (~ 1 mile east of the spill site).  They noted that the product was likely theirs as they had witnessed a slight drop in pressure in their discharge line (1000
psi down to ~ 960 psi).  The platform was shut in at approx 2200.  Shortly thereafter, pressure in the pipeline decreased to 750 psi.  Initially, there was concern that the downstream check valve in the line was not holding, causing back pressure from the other platforms and lines that feed the main trunkline.  However, pressure in the pipeline has decreased steadily over the past several hours to its current reading of 290 psi (as of 0300), indicating that the check valve is holding.  Additionally, BAYPORT has been monitoring the “fountain” with its radar and has noted that the signature is now barely visible.

Pipeline details:   12″ high pressure natural gas/condensate oil mixture line.  At normal operating pressure of 1000 psi, the pipeline typically produces 34.5 million cubic feet of natural gas per day and 230 barrels of condensate oil per day.  The condensate has an API gravity of 47 degrees (very light).  The pipeline has a 12 mile run between the rig in West Cameron Block 62 and the check valve and sub-sea shut-in valve in West Cameron Block 44.  The residual pressure in this 12 mile run must be released for the spill to stop.

Pipeline is owned by Stingray Enbridge.  They have assumed the role of responsible party and activated their incident management team.  O’Briens is the spill management contractor.  OSRO resources have been activated through Clean Gulf.

Estimate of spill volume: Based on max capacity of the line and a full-line breach w/unrestricted flow, the maximum discharge of hydrocarbon which would produce a sheen on the water (condensate only) over the previous 6 hours would be 60 barrels.  This is an upper bound.  We anticipate less than this amount as the pressure in the line has been significantly less than 1000 psi since the production rig was shut in at 2200.

Current actions: Continue to monitor pressures in the line.  AM overflights to assess pollution impact.  RP has established an incident command post at the O’Briens facility in Slidell.  MSULC has 1 rep at the command post, others to arrive in the AM.

Future actions:  RP has helo overflight scheduled for 0730 out of Lake Charles w/MSULC mbr onboard.  USCG fixed wing sched to depart out of Mobile, AL at 0800 w/Strike Team mbr onboard.  Stingray Enbridge is sending a dive boat out to WC Block 44 to manually close the sub-sea shut in valve.  This will complete the shut-in process.  ETA is noon.  Two Clean Gulf fast response boats are on standby w/4 hour onscene time to be activated as needed for spill cleanup.

Waterways impact: Calcasieu Ship Channel has been closed in the vicinity of the spill site with a 2 mile safety zone.  3 inboard and 2 outbound deep draft vessels are currently delayed.  Anticipate maintaining safety zone
until final shut-in is complete by the dive team and confirmation of no further gas/condensate discharge at the spill site.

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