Identifying Fire & Explosion Hazards

A fire or explosion is always a possibility in the upstream oil and gas industry. Why? Because two of the three things needed to make it happen are virtually always there – hydrocarbons as a fuel and oxygen in the air. Add an ignition source and the right conditions, and you have everything you need for combustion.

Expanded Fire Triangle

The diagram below shows the expanded lists of possible fuel, oxygen and ignition sources in the upstream oil and gas industry. These lists resulted from the research work and case studies provided on this web site. Please click on the diagram to view or print this important information.

Click on thumbnail for printable diagram

Eliminate one side of this triangle and you eliminate the potential for a fire or explosion. Sounds simple but it’s not given the dynamic nature of drilling, completion and well servicing operations. Factors to consider in this complicated issue include:

• Flammable/combustible substances are usually present and their properties can vary a lot due to the broad range of possible operating conditions.
• The ongoing concern that hydrocarbons could be accidentally released into the work area.
• There’s a wide range of situations where oxygen can knowingly or unknowingly be introduced.
• There are many potential ignition sources. Some not well understood and difficult to control such as static electricity and adiabatic compression.

On the other hand, having all three parts of the fire triangle does not guarantee an explosion. Given the complex mechanics of combustion, the probability of an explosion occurring in certain situations can be very high, however it is never absolutely certain. And that’s what makes this issue so difficult. Different results can happen in very similar situations. There are no guarantees that the same result will happen every time.

Improving Safety

Creating effective solutions to reduce the number of upstream fires and explosions depends on many things, two important steps are:

1. Developing a better understanding of all possible fuel, oxygen and ignition sources.
   
2. Conducting accurate and ongoing assessments of both the operational circumstances that exist in each situation and the barriers needed to address them.

Understanding Fire and Explosion Mechanics

Click on thumbnail for printable diagram

This simplified fault tree diagram shows how the hazards and barriers to address them must be examined for the possible ignition, fuel and oxygen sources found in each specific oil and gas operation. It is based on the Ball Energy Model. One important addition made after looking at the fire and explosion case studies was that with any ‘closed’ system, we must look at how oxygen may enter that system and the potential consequences of this happening.