Stuck Pipe Prediction in Utah FORGE Geothermal Wells

Abstract

Abstract Four stuck pipe events occurred during the construction of six geothermal wells in the Utah FORGE field, causing several hours of non-productive time (NPT). All of them could have been avoided if effective preventive measures and tools had been used. This paper provides an analysis of these events with the publicly available Utah FORGE dataset and discusses their predictability using a new hybrid approach that can in future be used to avoid stuck pipe incidences at Utah FORGE. Our analysis is primarily based on physics-based simulations combined with well information, such as trajectory, lithology, and the position of the drillstring (specifically the contact points) with respect to the geometry during the time the events occurred. Based on this detailed analysis, we implemented anomaly detection techniques in the time window before each stuck pipe event to automatically identify root causes. Following this, we formulated guidelines that combine the developed early stuck pipe event detection capability with accepted industry operational practices, to prevent similar stuck events in the future. The Utah FORGE stuck pipe events were found to be primarily related to wellbore geometry (i.e., mechanical stuck pipe) and use of non-optimum operational drilling practices. The incidents, analyzed in time domain after dimensional transformations, show clear early signs of anomalies in the time frame before their occurrence. This means they could have been detected and potentially prevented. The guidelines include recommendations for acting pro-actively on early stuck pipe indicators identified by real-time data analysis, as well as making appropriate additional changes during well planning and execution phases, such as changing the bottom hole assembly to be less sensitive to mechanical sticking. The work shows the high value of robust predictive models for stuck pipe prevention. The work will help reduce geothermal well construction (which is expected to expand significantly in the near future) cost by enabling better stuck pipe NPT avoidance. However, the approach is not specific to geothermal well construction and can be expanded to all drilling applications as well as stuck pipe incidents that are non-geometrical in origin. This paper therefore provides a new real-time data analysis system and effective guidelines which, if implemented, will enable better mitigation of stuck pipe risks on future wells.