Understanding the integrated performance of complex artificially lifted wells on ‘not normally manned’ (NNM), offshore platforms, without invasive techniques represents a challenge not only to minimizing operating costs, but also optimizing production and thereby maximizing value. Often the analysis of such problems is hindered by the complex interactions between identified production constraints and a lack of operating data.
The Cliff Head oilfield (offshore Western Australia) is developed with an innovative Coiled Tubing deployed Electrical Submersible Pump (CT-ESP) artificial lift system. This paper describes the process by which ESP and well data, in conjunction with a well performance modeling software, have been used as a powerful tool to diagnose well performance issues and optimize production. Production trends were created based on real time production data to understand ESP performance. Individual well models were created to identify potential causes of declining performance; in this case, the utilization of an ESP "performance limiting factor (PLF)" indicating deteriorating ESP performance due to solids build-up.
Based on the model results, chemical soaks were implemented on two production wells to remove flow restrictions within and around the ESPs. The treatments increased the oil production rates by 17% to 48%
Following a de-bottlenecking study, reservoir simulation in combination with detailed ESP performance analysis concluded that total field production improvements of up to 50% were possible. Consequently, the next phase of field development will install larger capacity ESP's.
This paper outlines how field data and desktop tools were combined successfully to monitor and diagnose well performance issues to deliver material production enhancements.