Well Pad Piping Displacement Beyond Limits Predicted During Design

Abstract Within a few years from start of operation in one of the gas fields in Oman, it was observed that well pad piping, of multiple wells, experienced movement higher than the expected range. This issue was tackled to understand better the potential root causes and prevent further movement in existing pads and excessive movement in the follow-up wells. In parallel, stress studies were undertaken to confirm that operation remains safe. It was concluded that flowline thermal expansion and slug forces were the most probable causes for the movement. This Suggests that thermal expansion impact and some operating scenarios have been underestimated during design phase. The flowline has most likely expanded considerably pushing the piping away from the support. Thermal expansion could be constrained or tolerated to some extent, slug forces can be limited by controlling the operating mode. The team recommended to monitor the situation and proposed actions to limit the movement and prevent escalation, which included, assessing acceptability of current stresses based on largest movement detected, proposing changes to current support configuration that would accommodate higher displacements, and limit the stresses experienced by the piping on the Well pad. The novelty is to adequately capture pipe displacement causes during design/modelling stage and improve mitigation measures in the design and operation for future wells.