Federal regulators, working with Walter Oil & Gas Corp., said Friday they were continuing to oversee and coordinate response efforts to secure the producer's South Timbalier Block 220 natural gas well in the shallow Gulf of Mexico (GOM), which blew out last Tuesday and ignited a fire later that night.
The flow of gas under pressure, which was feeding a fire on the Hercules Offshore Inc. platform, stopped on its own Thursday after sediment and sand flow restricted the leak. The rig and natural gas well are about 60 miles offshore Louisiana in a water depth of 154 feet. It was not producing at the time.
The Bureau of Safety and Environmental Enforcement (BSEE) and the U.S. Coast Guard (USCG) have turned their efforts to permanently plugging the well and investigating why it blew out -- and why the blowout preventer system on the rig failed to stop the accident. The Hercules 265 jackup drilling the well was built was built 31 years ago and certified by the USCG through July 4, 2017. A BOP system was approved for installation in November 2010, six months after the Macondo well blowout.
"Walter submitted to BSEE an application for a permit to drill a relief well, which includes proposals for the cement and casing programs," said regulators. "BSEE engineers are currently evaluating the permit, and BSEE continues to review and approve all operational plans and procedures related to the response."
Another Hercules rig was expected to arrive by the weekend to drill the relief well. However, a relief well may not be necessary now that the blown well has been bridged, said officials. Bridging is a well condition where small pieces of sediment and sand flow into the well path and restrict and ultimately stop the flow, authorities said.
"Work continues to secure the well, and all options are being considered for the most efficient and safe path forward," said BSEE and USCG. Firefighting equipment on marine vessels remained on site Friday with personnel from Walter, Hercules, Wild Well Control and engineering contractors, regulators said. The 225-foot USCG Cutter Cypress also was onsite "to assess the situation and enforce the 500-meter security zone around the rig."
A visual inspection of the area "indicated that the structural integrity of the rig remains intact," said BSEE. "A slight sheen was detected on the water's surface and is dissipating quickly. Air and gas monitoring equipment is being deployed around the perimeter of the well location to help ensure operations to secure the well remain safe. Safety of personnel and protection of the environment remain the top priorities for responding to the event."
Walter's A-3 well experienced a loss of control about 8:45 CDT on Tuesday while doing completion work on a sidetrack well. Forty-four personnel were evacuated safely hours before leaking gas ignited about 10:45 p.m. CDT that night. Walter was paying a dayrate of $101,000-103,000 to rent the Hercules rig for a two-month period due to end Thursday (July 25). Following maintenance, Arena Energy then had contracted for the rig for three months at a dayrate of $102,000-104,000.
Forty-four people were evacuated safely after the gas blowout. Hercules 265 was working on a sidetrack gas well owned by privately held Walter in water about 70 feet deep. The platform's crew had attempted to shut down the well using the blowout preventer (BOP), but workers didn't succeed before they had to evacuate for their own safety, Hercules stated.
The BOP collapsed and isolated the fire on Wednesday, which reduced the danger to the rest of the rig. However, it made a top kill operation remote, according to the USCG. The blaze caused the beams supporting the rig floor and the derrick of the cantilever to collapse over the rig structure. Offshore support vessels then were unable to safely put water on the rig, authorities said. By Thursday afternoon, the fire had "decreased to a small flame fueled by residual gas at the top of the well," said regulators.
BSEE and USCG conducted overflights to visually confirm that the leak had been contained and that the fire was almost out. The regulators plan to continue overseeing response efforts "until the event has come to a complete and safe resolution, which includes securing the well."
An investigation of the Macondo blowout three years ago found that the BOP on the Deepwater Horizon drilling rig had failed to work properly, which caused millions of gallons of crude to leak into the GOM. Since then, regulators have tightened some standards for BOPs, but a broader overhaul for equipment updates and other offshore safety changes is pending.
BSEE officials said they expect to propose new BOP regulations by the end of this year. An official said records to date indicate that in 10 incidents since Macondo's blowout, where loss of well control occurred, BOPs were activated successfully four times to seal the wells off. Other methods were used to stem the flow of oil and gas in the remaining six wells.
No shoreline impact is anticipated, according to the USCG, which Wednesday said the light sheen from the leaking well was dissipating.
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