Downhole Tractor Synchronization via Wireline Tension Feedback

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Solution Overview

Problem

In deviated wellbores, such as those from horizontally drilled wells, conventional methods using gravity to position tools with wireline cables often result in wasted power and traction due to mismatched speeds between wireline tractors and winches, leading to slack in the wireline and depth control issues.

Innovation Solution

Implementing a method to synchronize the speed of downhole wireline tractors and surface winches by adjusting the tractor speed based on real-time wireline tension readings, using proportional-integral (PI) or proportional-integral-derivative (PID) controllers to maintain nominal speeds, thereby minimizing slack and optimizing power usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the wireline tractor and winch are deployed at different speeds, then the tool can be positioned in distal regions of the wellbore, but wireline slack and wasted power occur

Engineering Contradiction:

Improvetractor speedVSAvoidwasted power and traction

Core Design Contradiction:

SpeedVSLoss of energy

Solution Approach 1:

The system continuously monitors wireline tension and uses this feedback to dynamically adjust tractor speed. When tension indicates the tractor is moving faster than the winch (causing slack), the system reduces tractor speed. When tension indicates the tractor is moving slower (causing excessive pull), the system increases tractor speed. This closed-loop feedback control eliminates wireline slack and prevents wasted power.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The tractor operates at variable speeds rather than a fixed speed, allowing it to dynamically adapt to the winch deployment rate. The system transitions from static speed control to dynamic speed adjustment based on real-time wireline tension conditions, enabling optimal synchronization between tractor movement and wireline payout.

Inventive Principle:

Principle #15Dynamics

2Productivity

If the wireline tractor moves faster than the winch deployment rate, then the tool can be conveyed deeper into the wellbore, but wireline slack occurs

Engineering Contradiction:

Improvetool conveyance speedVSAvoidwireline tension stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

Wireline tension sensors provide continuous feedback on the relationship between tractor speed and winch deployment rate. When slack is detected (tension decreases), the system immediately reduces tractor speed to match the wireline payout rate, restoring proper tension stability without significantly impacting overall tool conveyance productivity.

Inventive Principle:

Principle #23Feedback

3Stability of the object's composition

If the wireline tractor moves slower than the winch deployment rate, then wireline slack is reduced, but power and traction are wasted

Engineering Contradiction:

Improvewireline tensionVSAvoidtractor power consumption

Core Design Contradiction:

Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The feedback control system detects when wireline tension indicates the tractor is moving slower than the winch deployment rate (excessive pull condition) and automatically increases tractor speed to match the wireline payout rate. This prevents unnecessary power consumption and traction waste while maintaining adequate wireline tension.

Inventive Principle:

Principle #23Feedback

4Ease of manufacture

If conventional gravity-based tool positioning is used in vertical wells, then simple deployment is achieved, but it is ineffective for deviated wellbores

Engineering Contradiction:

Improvedeployment simplicityVSAvoidwellbore type adaptability

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The system introduces dynamic tractor-powered conveyance that adapts to different wellbore configurations. In vertical wells, the tractor can operate at low speeds with gravity assistance. In deviated and horizontal wellbores, the tractor increases speed and power to overcome gravity and friction, pushing the tool string through the wellbore. This dynamic adaptation enables the same system to handle both simple vertical deployments and complex deviated wellbores effectively.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11454076B2Method for synchronizing downhole tractor and winch deployment

Publication Date: 2022.09.27 HALLIBURTON ENERGY SERVICES INC

AI summary

A method for synchronizing downhole tractor and surface winch deployment includes inserting into a wellbore a tool string connected to a wireline, where the tool string includes a variable speed tractor. The method also includes deploying the tractor, and deploying the wireline from a winch. The method further includes dynamically monitoring, by a device disposed downhole, a wireline tension as an indicator of synchronization of the tractor and winch.