Downhole Linear Motor Phase Rotation Detection

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Solution Overview

Problem

In downhole linear motors used in oil wells, incorrect phasing of electrical connections can lead to inefficient operation, as the motor may be driven in the opposite direction of intended, resulting in reduced efficiency and production, due to misconnections during installation or maintenance.

Innovation Solution

A method and apparatus to determine proper phase rotation by monitoring the load on the motor during multiple cycles of operation, identifying which direction corresponds to the power stroke and return stroke based on increasing or constant current draw, allowing correct association of phase rotations with motor strokes and subsequent normal operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If electrical connections are made during installation or maintenance, then the motor can operate, but misconnection of conductors may occur resulting in reversed phase rotation and inefficient operation

Engineering Contradiction:

Improveease of connectionVSAvoidconnection accuracy

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system performs preliminary action by automatically detecting the correct phase rotation sequence before normal motor operation begins. The controller executes a detection routine that applies power in different phase sequences and monitors current draw to identify the correct configuration, preventing misconnection errors before they affect production efficiency

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback by monitoring the current draw during phase rotation detection. The controller measures current during different phase sequences and uses this feedback information to determine which phase rotation produces the expected current pattern, thereby identifying the correct connection configuration

Inventive Principle:

Principle #23Feedback

2Productivity

If phase rotation is not properly determined, then the motor may operate in reverse direction, but this reduces production efficiency and oil output

Engineering Contradiction:

Improveproduction efficiencyVSAvoidphase rotation information

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The system performs preliminary detection of phase rotation before normal operation. The controller executes a detection sequence that tests different phase rotations and identifies the correct one based on current draw patterns, ensuring that the motor is properly configured before full production operation begins

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system replaces manual phase rotation determination with an automated electronic detection system. Instead of relying on mechanical identification methods or manual testing, the controller electronically detects phase rotation by monitoring current draw patterns during automated test sequences

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If current draw is monitored during multiple cycles, then proper phase rotation can be identified, but this requires additional operational cycles and time

Engineering Contradiction:

Improvephase rotation detection accuracyVSAvoiddetection time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system uses partial action by monitoring current draw at specific critical points during the stroke cycles rather than continuously throughout entire cycles. This selective measurement approach maintains detection accuracy while reducing the total time required for phase rotation identification

Inventive Principle:

Principle #16Partial or excessive action

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 accurate determination of phase rotations, ensuring the motor operates efficiently by identifying the correct direction for power and return strokes, thereby improving oil production efficiency and reducing the risk of misconnections.

Implementation Method 1

The linear motor has a mover that moves in a linear, reciprocating motion. The mover drives a plunger-type pump to force oil out of the well.

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

Linear motors may use several sensors (e.g., Hall-effect sensors) to determine the electrical position and absolute position of the mover.

Methodology Applied

Scientific EffectHall effect: Hall Effect

Implementation Method 3

The mover drives a plunger-type pump to force oil out of the well.

Methodology Applied

Scientific EffectMechanical force: Mechanical Force

Data Source

PatentUS11695363B2Systems and methods for determining proper phase rotation in downhole linear motors

Publication Date: 2023.07.04 BAKER HUGHES CO

AI summary

Systems and methods for determining proper phase rotation in a linear motor that may be used in an ESP system, where the phase rotations associated with power and return strokes are initially unknown. The method includes providing power to the motor for multiple cycles and monitoring the load (e.g., by monitoring current drawn by the motor) on the motor to determine in which direction (phase rotation) the load on the motor increases. This direction corresponds to the power stroke of the motor. The direction of increasing load is then associated with the power stroke and the motor is operated normally.