Case Study 1.2
Location: Offshore Oil Rig, Abu Dhabi
Incident Overview:
On a typical day on an offshore oil rig in Abu Dhabi, the production operations were proceeding as usual. The day shift crew was responsible for a routine shutdown and maintenance of a key processing unit. During this maintenance, an unexpected incident occurred that led to a critical situation.
Description of the Incident:
As part of the scheduled maintenance, the day shift crew was instructed to shut down the processing unit. This involved isolating various valves and equipment to ensure safety during maintenance activities. However, during the shutdown process, a critical valve was inadvertently left partially open due to a misunderstanding among the crew members.
The consequence of this oversight was twofold. Firstly, the unintended valve position led to an unexpected increase in pressure within a crucial pipeline. This pressure exceeded the recommended maximum operating limit for the pipeline, creating a hazardous condition. Secondly, the maintenance team failed to detect a potential issue with the bolts securing a pipe flange during their routine inspection. These bolts did not have the required torque tightness to withstand the elevated pressure, resulting in a small leak of flammable hydrocarbons.
As a result of the leaking flammable product, a highly flammable atmosphere developed within the immediate vicinity of the pipe flange. Simultaneously, the increased flow of product exacerbated the situation by generating a buildup of static charge within the pipeline. Unfortunately, the electrical bonding of the pipeline was insufficient to dissipate this static charge safely. A spark was generated within the pipeline, igniting the leaked hydrocarbons and causing a sudden fire.
Emergency Response and Findings:
Upon detecting the fire, the rig’s advanced fire and gas detection system immediately triggered the emergency procedures. These procedures included the activation of the Emergency Shutdown (ESD) system, which swiftly isolated the affected section of the process to prevent further fueling of the fire. The ESD system also halted the entire processing unit. Additionally, the fire extinguishing system, employing inert gas, was promptly activated in the confined area to extinguish the fire.
Subsequent investigations revealed several significant shortcomings:
- Inadequate Training: The personnel involved in the process systems, especially during startup and shutdown procedures, were found to lack comprehensive training. There was a need for a deeper understanding of the potential consequences of their actions, emphasizing the importance of strict adherence to procedures.
- Maintenance Program Review: The investigation highlighted the necessity of reviewing the maintenance program in place. This review aimed to enhance its effectiveness, with a focus on identifying and rectifying potential issues, such as the torque tightness of bolts securing critical connections.
Conclusions:
The incident on the offshore oil rig in Abu Dhabi underscored the critical importance of proper training and adherence to procedures in the oil and gas industry. It served as a reminder that even minor oversights during routine maintenance tasks can lead to significant safety hazards. As a result, the industry committed to providing more rigorous training for personnel involved in process systems and reviewing maintenance programs to ensure safer operations.
