Petrel No. 1 Blowout in Australia (SEDCO 135G) Case Study by Bryan Atchison. Oil and Gas Blowout

Summary

This video tells the story of the catastrophic blowout at the Petrel 1 well in 1969, off the coast of Northern Australia. The well's uncontrolled flow of hydrocarbons led to a sea on fire, with footage never seen before. The incident was a result of human error, equipment failure, and inadequate procedures. Despite the challenges, there were no fatalities during the crisis. The video reflects on the lessons learned, the risks of well control, and the advancements made in the oil and gas industry over the last 50 years, emphasizing the importance of automated well control systems.

Takeaways

• 😀 The script describes a catastrophic well control failure that resulted in a sea fire, originating from the Petrol One well off the coast of Australia in 1969.
• 😀 The well control incident was caused by poor drilling and well control practices, leading to an excessive influx of gas into the well, which could not be managed effectively.
• 😀 Brian Atchison, the narrator, provides personal insight, as his father was involved in the blowout's recovery and the subsequent tragedy.
• 😀 The Sedco 135G drilling rig was used for the operation, featuring subsea equipment including preventers designed to control high-pressure situations.
• 😀 The incident began when the drilling rate increased unexpectedly, and the well started to flow. Despite attempts to close the annular preventer, the situation escalated.
• 😀 A critical failure occurred when the annular preventer failed while moving the drill pipe, leading to a violent mud discharge and loss of control of the drilling operations.
• 😀 The blowout led to fires on the rig floor and throughout the rig's accommodations, fueled by well gas that leaked through the riser pipe and into the rig.
• 😀 The safety of the vessel took priority, and the rig was moved away from the well using anchor winches. The riser eventually parted, stopping the fire's fuel supply.
• 😀 After the rig was evacuated, the gas plume rising from the seabed was ignited, creating a visible sea fire, which continued for several months.
• 😀 Despite extensive damage to the rig and no fatalities, a marine accident during the relief well operation caused the loss of nine lives, highlighting the persistent dangers in offshore drilling.
• 😀 The script emphasizes the importance of improving well control equipment, such as providing multiple annular preventers, and highlights advancements in automated well control systems to reduce human error and protect workers.

Q & A

What was the main issue in the Sedco 135G incident described in the script?

The main issue was a catastrophic well control failure during the drilling of the Petrel 1 well, which resulted in a blowout, fires, and significant damage to the rig and its equipment.

What was the cause of the blowout on the Sedco 135G rig?

The blowout occurred after an excessive influx of hydrocarbons entered the well, caused by poor drilling and well control practices, including human error and a failure in the annular preventer.

Why was the size of the influx significant in this incident?

The influx size was significant because larger influx volumes lead to higher well-killing pressures, putting more strain on the equipment and increasing the chances of catastrophic failure.

What role did human factors play in this blowout?

Human factors, such as errors in decision-making and failure to follow proper well control procedures, were central to the blowout. The reliance on human competency without adequate safeguards contributed to the disaster.

What steps were taken to try to control the well after the initial blowout?

After the blowout, attempts were made to control the well by pumping heavier fluid into the well and eventually cementing it. However, the annular preventer failed during this process, leading to further loss of control.

What happened when the riser pipe started to clash with the rig's substructure?

When the riser pipe clashed with the rig's substructure, there was an unsuccessful attempt to disconnect the subsea equipment, and gas began flowing from the well to the rig, leading to fires on the rig.

How were the fires controlled after the blowout?

The rig was moved away from the well, and when a safe distance was achieved, the gas plume ignited. Once the rig crew returned and the fires were extinguished, a damage assessment was conducted.

What happened during the relief well drilling operation?

While drilling the relief well, a marine accident occurred on the setco Helen workboat, resulting in the loss of nine personnel. The incident highlighted further risks during the operation.

What are some key lessons learned from the Sedco 135G incident?

Key lessons include the importance of keeping the drill pipe stationary during well control operations, using higher-rated BOP equipment, and incorporating automated well control technologies to reduce human error.

How has the well control industry evolved since the Sedco 135G incident?

The well control industry has significantly improved, with higher standards for equipment, procedures, and technology. Innovations such as automated well control tools now help reduce human error and enhance safety.