Distributed Temperature Sensing Monitoring of Well Completion Processes in a CO₂ Geological Storage Demonstration Site

• Main Authors: Dasom Sharon Lee, Kwon Gyu Park, Changhyun Lee, Sang-Jin Choi
• Format: Article
• Language: English
• Published: MDPI AG 2018-12-01
• Series: Sensors
• Subjects: distributed temperature sensing; temperature calibration; depth correction; fiber optic sensing; well completion monitoring
• Online Access: https://www.mdpi.com/1424-8220/18/12/4239

The Distributed Temperature Sensing (DTS) profiles obtained during well completion of a CO₂ monitoring well were analyzed to characterize each well completion process in terms of temperature anomalies. Before analysis, we corrected the depth by redistributing the discrepancy, and then explored three temperature calibration methods. Consequently, we confirmed the depth discrepancy could be well corrected with conventional error redistribution techniques. Among three temperature calibration methods, the conventional method shows the best results. However, pointwise methods using heat coil or in-well divers also showed reliable accuracy, which allows them to be alternatives when the conventional method is not affordable. The DTS data revealed that each well completion processes can be characterized by their own distinctive temperature anomaly patterns. During gravel packing, the sand progression was monitorable with clear step-like temperature change due to the thermal bridge effect of sand. The DTS data during the cementing operation, also, clearly showed the progression up of the cement slurry and the exothermic reaction associated with curing of cement. During gas lift operations, we could observe the effect of casing transition as well as typical highly oscillating thermal response to gas lifting.