Wireline Impedance Estimation for Downhole Tool Voltage Control
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Solution Overview
Problem
Existing wireline operations in hydrocarbon recovery struggle to accurately and continuously determine wireline impedance during downhole tool deployment, which limits the control response time for regulating downhole tool bus voltage.
Innovation Solution
The method involves continuously determining the wireline impedance by measuring DC resistance and AC aspects, such as wireline armor resistance and inductance, while the downhole tool is powered up and deployed, using surface and downhole sensors and injecting a step signal into the wireline.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wireline parameters are determined using conventional DC resistance measurement only, then the measurement process is simple, but the control response time is slow and accuracy is limited
Solution Approach 1:
The patent transitions from static DC resistance measurement to dynamic AC impedance measurement by injecting a step signal and measuring the transient response. This dynamic approach captures both resistive and reactive components of wireline impedance, improving measurement accuracy while accounting for the time-varying nature of wireline parameters during deployment.
Solution Approach 2:
The patent changes the measurement parameter from pure DC resistance to AC impedance by introducing a step signal. This parameter change enables capture of both resistive (DC) and reactive (AC) components of the wireline impedance, providing a more complete characterization of wireline electrical properties during runtime.
2Productivity
If wireline parameters are determined with the downhole tool powered down, then the measurement can be performed, but the parameters cannot be continuously updated during deployment
Solution Approach 1:
The patent enables continuous wireline impedance measurement during runtime by performing measurements while the downhole tool remains powered on. The measurement system continuously monitors impedance parameters throughout deployment, ensuring up-to-date information is available for real-time control decisions without interrupting tool operations.
Solution Approach 2:
The measurement system is integrated into the operational system itself, using the existing power and signal paths to perform impedance measurements. The downhole tool's own operational circuits are utilized for measurement purposes, eliminating the need for separate measurement modes or external measurement equipment.
3Measurement precision
If a step signal is injected to determine AC aspects of wireline, then accurate impedance measurement is achieved, but additional control steps are required
Solution Approach 1:
The patent combines the impedance measurement function with the existing operational signal path. The step signal injection and measurement process is integrated into the normal operational sequence, merging measurement and control functions into a unified system that performs both tasks without requiring separate operational modes.
Solution Approach 2:
The patent implements a feedback mechanism where the measured impedance parameters are continuously fed back to update the control model. This feedback loop enables real-time adjustment of control parameters based on actual wireline conditions, improving control accuracy while automating the measurement and update process.
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
This approach enables accurate and fast regulation of the downhole tool bus voltage, improving control accuracy and response time by continuously updating wireline parameters during runtime.
Implementation Method 1
the wireline may provide power and communication between a surface system and downhole systems
Implementation Method 2
the unspooling of the wireline cable may cause the wireline impedance to change
Data Source
AI summary
A method comprises deploying, in a borehole, a downhole tool coupled to a surface system by a wireline and repeating the following operations while the downhole tool is powered on and being deployed in the borehole, obtaining surface measurements, via surface sensors, and downhole measurements, via downhole sensors, determining a DC resistance of the wireline based on the surface measurements and the downhole measurements, injecting a step signal into the wireline from the surface system, determining AC aspects of the wireline based the surface measurements and the downhole measurements at a time period after injecting the step signal into the wireline, and controlling a bus voltage of the downhole tool based on the DC resistance and the AC aspects.