Long-Service-Life Distributed Temperature Sensing System

Zitn's Long-Service-life Distributed Temperature Sensing (DTS) system is a highly reliable temperature monitoring solution specifically engineered for long-term downhole or embedded infrastructure surveillance. Utilizing high-temperature-resistant specialty optical fiber and an industrial-grade interrogator, the system operates on the principles of Raman backscattering and Optical Time-Domain Reflectometry (OTDR). It enables continuous monitoring over tens of kilometers of sensing cable, achieving centimeter-level spatial resolution and a temperature accuracy of ±0.2℃. Featuring exceptional long-term stability, immunity to electromagnetic interference, and corrosion resistance, the system is capable of round-the-clock, unattended operation. It is widely applied in injection/production profiling, pipeline leak detection, and underground gas storage safety monitoring, providing real-time data support for the full lifecycle management of energy assets.

Applications

1. Payzone Dynamic Identification & Productivity Evaluation

• Application Description: Continuously monitor the temporal evolution of the borehole temperature profile using permanently installed DTS fiber optic cables on the production tubing or outside the casing.

• Value:

• Clearly identify fluid contribution from each pay zone (oil, gas, or water producing intervals).

• Dynamically assess changes in single-well productivity to guide production allocation and zone adjustment operations.

2. Water/Gas Injection Profiling & Displacement Efficiency Evaluation

• Application Description: Deploy permanent DTS in injection wells to capture thermal anomalies caused by the injected fluids in real-time.

• Value:

• Accurately locate where injected fluids enter the formation (injection profile).

• Detect "fingering" or channeling to optimize injection/production strategies and improve sweep efficiency.

3. Monitoring of Artificial Lift Systems (Gas Lift / ESP)

• Application Description: In wells utilizing artificial lift methods such as gas lift or Electric Submersible Pumps (ESP), DTS monitors the thermal response during the lifting process.

• Value:

• Evaluate the operational status of gas lift valves or the reasonability of pump setting depth.

• Detect pump overheating, gas interference, or abnormal fluid levels early to prevent equipment damage.

4. Casing Integrity & Annular Leakage Diagnosis

• Application Description: Utilize permanent DTS to monitor thermal anomalies outside the casing or in multi-layer annuli.

• Value:

• Identify cross-flow, cement bond failure, or casing leaks (e.g., high-temperature fluids migrating from deep zones to shallow sections).

• Provide precise location data for wellbore remediation (e.g., squeeze cementing).

5. Full Lifecycle Monitoring of Thermal Recovery Processes (Steam Flooding / SAGD)

• Application Description: Permanent DTS serves as a core monitoring tool in heavy oil thermal recovery wells (e.g., Cyclic Steam Stimulation, SAGD).

• Value:

• Track the extent and shape of the steam chamber in real-time.

• Optimize steam injection parameters to prevent premature thermal breakthrough.

• Evaluate thermal recovery efficiency and extend the economic life cycle of the well.

Technical Specifications