Novel ADNOC Offshore Experience in Managing Wells Beyond Design Life

Abstract Several wells operated beyond the design life may show no abnormality during routine monitoring. However, proactive action is required to evaluate the perceivable and unperceivable risks. Oil and gas wells that have exceeded their design life may pose several hidden risks, including structural integrity, formation damage, environmental risks, costly maintenance, compliance, liability, and finally abandonment and decommissioning requirements. The paper will try to identify a method statement and a workflow for such wells which are in practice in the company. The current risks of the identified wells are evaluated based on routine monitoring and maintenance information. With the support of well integrity database existing workflow, automated alerts have been introduced to notify the engineers about any discrepancy. Review of the corrosion prediction to establish the more relevant operating limits have enabled the engineers to manage and ascertain the risks The wells are further analyzed with the historical trend analysis, past interventions, latest well recompletion, operating limits evaluation, past applying lesson learnt etc. Gathering of related data is a critical step towards meaningful evaluation and risk identification. This enables us to leverage the automated risk assessment with the well integrity software to immediately capture the appropriate risk level. Barrier failure prediction is the key to ascertaining the well integrity to enable the company to take proactive action to avoid production interruptions for risk escalation. Any additional hazards need to be evaluated based on past events that occurred locally and internationally. An exhaustive list of tasks for identification of the probable hazard scenarios has been generated and its consequence on the well evaluated. This paper will discuss the workflow and robust methodology to be considered for the evaluation of different scenarios of well barrier failure. The intention is to have a minimum set of data requirements and diagnostics which will provide additional data to supplement the evaluation. These identified wells to have additional risk evaluation considering additional obtained information. Some of the issues identified could be wells with deteriorated casing thickness, wells with zero annulus pressure, wells with degraded cement across aquifers etc. An evaluation matrix will help in identifying a well with hidden hazards which may impact the current risk level. Based on the evaluated data a prioritization of control measures along with quantified risk gives visibility and assurance for continued operations for the remaining life of well. This paper can benefit professionals managing integrity of aging wells operating beyond the life of the well. The aim of all companies is to operate wells with ALARP well risks. There is no structured evaluation methodology available for evaluating the remnant well life, the paper attempts to create a methodology and workflow for evaluation. Accordingly, risk assessments need to be performed to provide assurance to company management as regards the continued operability of such wells with 100% HSE focus.