Root Cause Analysis of 8-Inch FRP Pipeline Failure That Resulted in a Spill and Fire

Abstract

Fibreglass reinforced plastic pipe (FRP) is the second most common type of pipe in the Canadian oil and gas industry, based on installed length. Industry methods to define risks and prevent failures are difficult because industry is still learning how these types of materials fail. Current industry failure records indicate that the failure rates for some of these materials are higher than steel failure rates. Unique details related to a specific FRP failure will be discussed in this paper. This failure occurred on an 8-inch OD FRP pipeline at the bottom of a riser. The failure resulted in a spill and a fire. The reasons for failure and fire initiation were analysed separately. The failure was a result of a combination of several types of stresses and material degradation. Both static and dynamic stresses contributed to the failure. • Ground settling resulted in high static bending stress of the last section of the pipeline connected to the riser elbow supported by the anchor. • The failure was in the last connection of the pipeline. Static tie-in stresses could have contributed to the failure. • Static stresses were evaluated using Finite Element Analysis (FEA) approach and found to be insufficient for the failure. • Dynamic stresses contributed to the failure. The failure happened soon after a power outage, when numerous wells were restarted, and several fluid surges may have occurred. • Material degradation associated with a specific orientation of glass fibres at the connection pup contributed to the failure. The failure sequence was established and different modes of fire initiation were analysed.