Downhole Tool Electrical Control via Brushed DC Motors
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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 use of electrical conductors and sensitive electronics in hostile environments.
Innovation Solution
A system and method for electrically operating and controlling multiple downhole flow control devices using brushed DC motors, minimizing the number of electrical connections through Tubing Encased Conductors (TEC) and incorporating position indication via power draw variations and current lapse time algorithms, with components positioned below the tubing hanger to reduce electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple downhole well tools are electrically actuated using separate electrical conductors, then each tool can be reliably controlled, but the number of electrical conductors increases
Solution Approach 1:
The patent combines multiple electrical conductors into a single multi-conductor cable that carries power and control signals to multiple downhole tools. Each tool is assigned specific conductors within the cable, merging what would otherwise be separate connection paths into a unified electrical infrastructure, thereby reducing the total number of individual conductor lines required
Solution Approach 2:
The electrical conductors are designed to serve multiple functions: providing power to multiple different downhole tools, carrying control signals bidirectionally, and enabling both actuation and diagnostic capabilities through the same physical medium. This multi-functionality eliminates the need for dedicated separate conductors for each tool or function
2Ease of operation
If sensitive electronics are used in downhole well tools, then precise control is achieved, but the system becomes vulnerable to hostile downhole environments
Solution Approach 1:
The patent employs simple, robust electrical components such as brushed DC motors and basic electrical switches that can withstand harsh downhole conditions. These components are designed to be durable and maintenance-free for the duration of the well's operational life, sacrificing the precision of sensitive electronics for the reliability of rugged, environment-resistant components
Solution Approach 2:
The system uses the electrical power supply itself as the communication medium, modulating the power signal to encode control commands and status information. This eliminates the need for separate sensitive electronic communication circuits, as the existing power conductors serve dual purposes for both energy delivery and information transfer
3Adaptability or versatility
If multiple electrical connections are made at the tubing hanger, then complete electrical control is achieved, but the system complexity increases
Solution Approach 1:
The patent divides the electrical control system into distinct segments, with each downhole tool having its own dedicated motor and control circuitry independent of other tools. This modular segmentation allows each tool to be controlled individually through the multi-conductor cable while maintaining electrical isolation between tools, simplifying the overall system architecture despite the multiple connections required
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
Enables efficient and reliable control of downhole tools with reduced complexity and increased durability, allowing selective production or injection into isolated well zones with minimal electrical noise and enhanced position feedback.
Implementation Method 1
actuator assembly configured to displace a closure member of the downhole well tool, the actuator assembly comprising a brushed DC motor
Implementation Method 2
incorporating position indication via power draw variations and current lapse time algorithms
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.