Single-Conductor Downhole Tool Control Using Motor Current Sensing
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Solution Overview
Problem
Existing technologies face challenges in electrically actuating multiple downhole well tools with minimal electrical conductors and without sensitive electronics in hostile environments, necessitating improvements for efficient control of downhole operations.
Innovation Solution
A system utilizing Tubing Encased Conductors (TEC) to minimize electrical connections, combined with brushed DC motors and position indication through power draw variations, enables the electrical actuation of multiple downhole flow control valves using a single conductor umbilical, minimizing complex electronics and optimizing power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple electrical conductors are used to actuate multiple downhole well tools, then the control capability and reliability are improved, but the complexity of the umbilical and installation difficulty increase
Solution Approach 1:
The patent combines multiple control functions into a single conductor system. The wellhead controller selectively applies voltage between a single conductor and the wellbore casing to actuate multiple downhole tools (valves, packers, etc.) along the wellbore, eliminating the need for multiple separate conductors for each tool.
Solution Approach 2:
The single conductor serves multiple functions: it provides electrical power, control signals, and actuation for various downhole tools at different depths. The system can selectively actuate different tools by controlling the voltage application points along the conductor's length.
2Extent of automation
If sensitive electronics are used in downhole well tools, then the control precision and automation are improved, but the reliability in hostile downhole environments deteriorates
Solution Approach 1:
The patent extracts the sensitive electronics from the harsh downhole environment and places them in the benign surface environment. The wellhead controller located at the wellhead (surface level) performs all electronic control functions, while the downhole tools contain only simple electromagnetic actuators that respond to voltage applied between the conductor and casing.
Solution Approach 2:
The patent introduces an intermediary system at the wellhead that mediates between the surface control electronics and the downhole tools. The wellhead controller acts as an intermediary, converting control signals into voltage applications that actuate the downhole tools through the conductor-casing circuit, protecting sensitive electronics from the hostile environment.
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 allows for efficient and reliable control of downhole tools by reducing the number of electrical conductors and eliminating sensitive electronics, enhancing operational efficiency and durability in harsh conditions.
Implementation Method 1
brushed DC motors
Data Source
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.