Downhole TEC Resistance Monitoring for Fault And Fluid Event Detection
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Solution Overview
Problem
Existing methods fail to accurately diagnose failures in downhole tubing encased conductors (TEC) due to error accumulation during resistance calculations, which are affected by short circuits, open circuits, or leakage currents, and do not effectively monitor downhole fluid events or predict TEC degradation.
Innovation Solution
Sequentially powering on downhole gauges to calculate TEC resistance incrementally, leveraging correlations between resistance and temperature to determine average temperatures and detect fluid events, and establishing a model for TEC degradation based on historical resistance data to predict failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If resistance calculations are performed using existing methods, then TEC resistance can be calculated, but error accumulation occurs during resistance calculations affecting diagnostic accuracy
Solution Approach 1:
The patent divides the continuous resistance calculation into discrete segments between individual downhole gauges. By calculating resistance incrementally between each gauge pair rather than continuously over the entire TEC length, the method isolates error accumulation to manageable segments that can be individually validated and corrected.
Solution Approach 2:
The patent implements feedback mechanisms where measured resistance values from downhole gauges are continuously compared against calculated values. When discrepancies exceed thresholds indicating potential TEC faults, the system adjusts subsequent calculations and triggers diagnostic procedures, creating a closed-loop system that corrects errors in real-time.
2Measurement precision
If downhole gauges are powered on sequentially to reduce error accumulation, then resistance measurement accuracy improves, but system complexity increases
Solution Approach 1:
The patent makes the power distribution dynamic by enabling individual downhole gauges sequentially rather than keeping all gauges powered continuously. This dynamic power management allows the system to activate only the necessary gauges for current measurements, reducing overall power consumption while maintaining measurement accuracy.
Solution Approach 2:
The system employs periodic action by cycling through downhole gauges in sequences, activating each gauge only when its resistance measurement is needed. This periodic activation pattern reduces continuous power requirements while ensuring all necessary measurements are taken at appropriate intervals.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Accurately identifies TEC faults and fluid events by reducing error accumulation, predicting failure locations, and monitoring fluid flow, thereby enhancing the reliability and efficiency of downhole operations.
Implementation Method 1
one or more tubing encased conductor (TEC) can be used. A TEC connects to the downhole gauges which have been installed in the borehole
Implementation Method 2
leveraging correlations between resistance and temperature to determine average temperatures
Data Source
AI summary
A method comprises monitoring a resistance over time of a tubing encased conductor (TEC) that electrically connects a first downhole gauge to a second downhole gauge positioned in a borehole deeper than the first downhole gauge. The method includes detecting that a first TEC fault has occurred in the TEC, in response to a change in the resistance being greater than a fault occurrence threshold and in response to an amount of the time of the change being smaller than a fault time threshold.