SOUTH TIMBALIER 220 BLOWOUT
July 23, 2013 U.S. Gulf of Mexico (G.O.M)
Overview
Well A3, in the South Timbalier Block 220 was located 84 miles South of Houma, Louisiana in ~ 154 ft of water. Jack-Up Rig 265 operated by Hercules Offshore Inc. was cantilevered against the South Timbalier 220 A Platform. Well A3 was being recompleted against productive sands at 8,800 ft MD.
The well was originally drilled in 2006 by the Ocean Crusader, a Matt-type Jackup Drilling Rig operated by Diamond Offshore. The block was operated by Walter Oil & Gas.
The Incident
On 23rd July 2013, when tripping out pipe after perforations, the well experienced an uncontrolled release of natural gas along with small amounts of gas condensate. On the day of the blowout, a light sheen of hydrocarbons was reported on the surface of the water (~ 50 ft wide and 0.5 miles long).
The A3 well continued to release natural gas into the environment for 13 hours after which it ignited engulfing the drilling rig on fire. After the ignition, the spread of hydrocarbons into the environment had reduced since a significant volume of gas had been consumed by the fire.
A large amount of sand was being produced with the gas from the source. Due to the sand content, the flow path from the reservoir to the surface was eventually bridged through the formation of a natural bridge plug. In a week’s time, by 1st August 2013, the hydrocarbon sheen on the surface of the water had dissipated and was no longer visible.
The Aftermath
Due to the extreme damage caused by the incident and the high sand content, there was significant debris around the well. Debris removal commenced on 2nd August 2013 using the Derrick Barge ‘Performance’. Walter Oil and Gas contracted the Rowan EXL-3 Jackup Rig and began drilling a relief well on 4th August 2013.
The A3 well continued to release natural gas into the environment for 13 hours after which it ignited engulfing the drilling rig on fire. After the ignition, the spread of hydrocarbons into the environment had reduced since a significant volume of gas had been consumed by the fire.
A large amount of sand was being produced with the gas from the source. Due to the sand content, the flow path from the reservoir to the surface was eventually bridged through the formation of a natural bridge plug. In a week’s time, by 1st August 2013, the hydrocarbon sheen on the surface of the water had dissipated and was no longer visible.
Way Forward
The decision was made to drill a relief well and reduce the reservoir pressure through production. As of 18th September 2013, the pressure in the reservoir was estimated at ~ 5,845 psi. Production from the relief well began on 24th February 2014. The well produced at 20 MMscf/Day of Gas with a condensate yield of 1.0 bbl/MMscf. By May 2014, water production had increased to 60 bbl/MMscf and Gas production dropped significantly.
Reference
Safety and Environmental Management Systems Accident Investigation Report, Part 1 – Root Cause Investigation Results, SEMS Incident Investigation Team, August 29, 2014.
