Evaluation and Comparison of Injection and Production Indices of Feed Zones and Wells Obtained from Spinner Logs Measured During Injection and Production Testing

Abstract

The Theistareykir power-plant in N-Iceland started operation at 45 MW in 2018 after 8 production wells had been completed in the years 2016-2017. During the drilling of these wells extensive data was collected and all the wells were injection tested at the end of drilling. The injection testing involved spinner logging to map the flow characteristics of the wells, notably the feed zones. In this paper we firstly describe the method used to process the spinner logs to produce downhole profiles of fluid velocity and mass flow. Secondly, we compare the injection indices of individual feed zones to the total injectivity index of each well. Thirdly we compare the injection and production indices of the wells to see how predictive the injection index of the well´s production capacity. Lastly, we compare production and injection spinner logs in well THG-15. This well was spinner logged while the well was discharging. The spinner logs are analysed in the same way as the spinner logs during injection. The resulting fluid velocity profile is compared to the fluid velocity profile from injection testing. The outcome is evaluated to give an idea of the relationship between the wells flow characteristics during injection and production testing.