Downhole Tool Electrical Control via Shared Power and Feedback Lines
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Solution Overview
Problem
Existing technologies face challenges in efficiently controlling multiple downhole well tools using electrical power from the surface while minimizing the number of electrical conductors and reducing the use of sensitive electronics in hostile environments.
Innovation Solution
The system utilizes multi-core Tubing Encased Conductors (TEC's) to minimize the number of lines to the surface and places a portion of the surface control system below the tubing hanger, using electrical actuation methods with position indication through power draw variations and current algorithms to control downhole flow control valves or interval control valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple electrical conductors are used to control multiple downhole well tools, then the control capability and reliability are improved, but the complexity of the system and the number of connections to surface are increased
Solution Approach 1:
A single electrical conductor performs multiple functions: it serves as the power supply for the DC motor and simultaneously as the communication pathway for bidirectional signals (actuation commands from surface and position feedback from downhole). This eliminates the need for separate conductors for power and communication, resolving the contradiction between control capability and conductor数量
Solution Approach 2:
The downhole well tool uses the power supply conductor itself to carry position feedback signals back to the surface. The tool modulates the existing power conductor to convey position information, rather than requiring a dedicated feedback conductor. This self-service approach maintains reliable control while minimizing the number of conductors needed
2Measurement precision
If sensitive electronics are used in downhole well tools for control and feedback, then the measurement precision and control accuracy are improved, but the reliability in hostile downhole environments deteriorates
Solution Approach 1:
The sensitive electronic control system is extracted from the hostile downhole environment and relocated to the surface where conditions are benign. Only simple, robust components (DC motor, mechanical position sensor) remain downhole, while the complex electronics for processing feedback and generating control signals are positioned at the surface, resolving the contradiction between measurement precision and environmental reliability
Solution Approach 2:
A purely mechanical position indication mechanism (cam follower system) serves as an intermediary between the mechanical valve position and the electrical conductor. This mechanical system converts position into electrical signals without requiring sensitive downhole electronics, maintaining measurement precision while improving reliability in the hostile environment
3Measurement precision
If traditional electrical actuation systems are used with separate power and signal conductors, then the control precision is improved, but the number of electrical connections and system complexity are increased
Solution Approach 1:
The power supply function and communication function are merged into a single electrical conductor. The same conductor that delivers power to the DC motor also carries the bidirectional signals for actuation commands and position feedback, eliminating the need for separate signal conductors and reducing overall system complexity while maintaining control precision
Solution Approach 2:
The electrical conductor is designed to perform multiple functions simultaneously: power transmission, command signal transmission, and feedback signal transmission. This multi-functional conductor reduces the total number of connections required while maintaining the precision control capabilities needed for accurate valve positioning
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 reduces the number of electrical connections required and provides efficient control of downhole tools, enabling selective production or injection into isolated well zones with improved reliability and reduced wear on components.
Implementation Method 1
an integral DC powered actuator assembly
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A system for use with a subterranean well can include a system controller with a computer, a power supply and at least one current sensor, multiple downhole well tools, each of the downhole well tools including a motor and a member displaceable by the motor; and an umbilical connected between the system controller and the downhole well tools, at least one conductor of the umbilical being connected to the motor of each of the downhole well tools. A downhole well tool example can include an actuator assembly configured to displace a member of the downhole well tool, the actuator assembly including a motor, a load yoke displaceable by the motor, and an elongated position indicator bar having at least one profile formed thereon. Friction between the load yoke and the position indicator bar varies as the load yoke displaces relative to the position indicator bar.