Correlation of Reservoir Monitoring and Continuous Production Data to Interpret Unexpected Well Behavior in Rotokawa

Abstract

Production monitoring helps to ensure reliable and sustainable mass supply from the production wells to the power stations through up to date information on changes to well behaviour. Correlated with other reservoir surveillance methods, production monitoring data were used to capture and interpret unexpected well responses in the Rotokawa field. This paper highlights the integration of various reservoir engineering methods used to monitor and evaluate well behaviours by Mighty River Power. A sample production well, RK14, was analysed based on observed production changes using (1) tracer flow testing (TFT) data, (2) pressure, temperature and spinner (PTS) analysis, (3) deliverability curves, (4) conceptual well models, and (5) wellbore modelling to understand possible subsurface changes causing the observed conditions at wellhead. The result showed an improvement in reservoir pressure support to the well as the main cause for the observed productivity increase. The changes to well behaviour were used to update the total flow capacity forecast and highlighted the need for further investigation to fully understand the reservoir’s response to production.