Failure Analysis – The Big Picture

The floating drilling rig, operating in 6,000 ft. of water, pitched in rough seas 300 miles away from shore as the outer bands of the hurricane’s winds buffeted the drilling location. Per procedure, the crew installed the Storm Packer (SP) in the well to isolate its open wellbore from the ocean before the storm roared across the location – but it failed its pressure test. The crew then installed the back-up SP which passed the pressure test. The well was finally secured, and the 25,000-ton drilling rig was moved out of the hurricane’s path.  Because the first SP failed, a 12-hour process took 30 hours to complete, while wind speed and wave heights increased.

An SP is used to temporarily abandon an offshore well during drilling or workover operations and is one component in a system of barriers that prevents the accidental discharge of hydrocarbons into the ocean. A failure could have hazardous consequences. In this example, the back-up worked, but why the first failed is unknown. A Failure Analysis will be conducted.

Not all equipment failures result in a hazardous situation, but all failures hurt a business’ bottom line. In the upstream energy business, failures in offshore applications have the highest impacts (rig time, the potential for loss of well control, and environmental damage), but failures in land wells also have significant economic impacts (loss of access to reserves, intervention). In many cases, the potential for human injury or fatality exists.

A thorough failure analysis is always necessary to confirm the root cause of a failure (product, process, or human factors), and identify mitigations that prevent future incidents. This series of articles will cover these elements of a thorough failure analysis:

• Scope
• Informational Collection
• Root Cause Analysis
• Failure Simulation
• Mitigation

The SP failure above did not result in an HSE incident, but there was significant economic loss, including drilling rig spread time (measured in $1,000,000s per day) and OEM brand damage.  

This is the 1^st in a series of six articles on Failure Analysis for downhole tools.

1. The Big Picture
2. Scope
3. Information Needs
4. Root Cause Analysis
5. Failure Simulation
6. Mitigation