A Comparative Analysis of Conventional ESP and Fiber-Optic Distributed Sensing (DTS/DAS)

Abstract This paper compares traditional Electric Submersible Pump (ESP) downhole sensors with fiber-optic distributed sensing technologies (Distributed Temperature Sensing, DTS, and Distributed Acoustic Sensing, DAS) in a producer well. The comparison focuses on the reliability and accuracy of downhole temperature gradient measurements, opportunities for deeper diagnostics and optimization, and practical data analysis workflows using DTS/DAS outputs versus point-sensor data. An ESP-equipped well was deployed with both conventional downhole sensors and a permanently installed fiber-optic cable. DTS used an optical fiber along the production tubing as a linear temperature sensor (continuous temperature profile along the wellbore), while DAS used the same fiber to detect acoustic vibrations along the well, turning the fiber into a distributed microphone that "listens" to the pump and flow. Data from both systems were cross validated and calibrated against ESP gauge readings, enabling direct comparison of point-based versus distributed measurements for enhanced ESP diagnostics. Analysis included gradient analysis, spectral decomposition for DAS signals, and temperature anomaly detection. Fiber-optic DTS demonstrated superior spatial resolution (1m) and stability compared to point-based ESP sensors, which provides an ability to identify temperature anomalies associated with gas entry, zonal inflow, and water breakthrough invisible to single-point measurements. DAS captured ESP operating frequencies and sensed acoustic shifts which can detect gas locking and early pump degradation, providing failure indicators unavailable from conventional sensors. Unlike traditional gauges susceptible to drift and failure in harsh downhole environments, the passive fiber-optic system remained stable and interference-free throughout deployment. DTS measurements matched ESP sensor values at some of the reference depths, confirming calibration accuracy. While conventional ESP sensors remain valuable for real-time control, fiber-optic data added crucial diagnostic depth. Instrumentation testing confirmed fiber optics as a practical, high-value addition to ESP surveillance systems. This paper presents the first data-driven comparison of DTS/DAS fiber optics versus conventional ESP sensors.