Lockable Reamer Cam Mechanism for Safe Retrieval

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Solution Overview

Problem

During the retrieval of under-reaming tools in the oil and gas industry, the differential pressure can cause hydraulically activated cutters to extend and damage the casing or the tool, especially during debris clean-out operations where simultaneous rotation and fluid circulation are necessary.

Innovation Solution

A downhole tool with an extendable cutting member and a hydraulically actuated cam member lock that can be activated to restrict movement, allowing the cutting member to be locked in a retracted position, preventing extension and enabling safe fluid circulation during retrieval.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the under-reamer is made hydraulically activated for easy operation during reaming, then the cutting member can be easily extended and retracted, but during retrieval the differential pressure may cause the cutting member to extend unintentionally and damage the casing or tool

Engineering Contradiction:

Improveease of cutting member extensionVSAvoidrisk of unintentional cutting member extension

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The cam member is designed to be movable between extended and retracted positions, allowing dynamic adjustment of the cutting member. The hydraulic activation enables easy extension during reaming operations, while the locking mechanism provides stability during retrieval, resolving the contradiction between ease of operation and reliability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

A locking mechanism acts as an intermediary between the hydraulic system and the cutting member. This intermediary component allows the hydraulic pressure to extend the cutting member during reaming, but prevents unintentional extension during retrieval by blocking the cam member's movement, thus resolving the contradiction.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If the cutting member is extended to perform reaming operations, then the bore diameter can be enlarged, but during retrieval the cutting member may contact and damage the casing lining

Engineering Contradiction:

Improvebore enlargement capabilityVSAvoiddamage to casing

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The locking mechanism is activated in advance during retrieval operations to prevent the cutting member from extending. This preliminary action ensures that when the drill pipe is pulled from the well bore, the cutting member remains retracted and cannot contact or damage the casing lining, while still allowing bore enlargement during actual reaming operations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The cutting member is designed with dynamic positioning capability, allowing it to be extended during reaming for productivity and retracted during retrieval to prevent damage. The locking mechanism enables this dynamic state change, resolving the contradiction between bore enlargement capability and casing protection.

Inventive Principle:

Principle #15Dynamics

3Productivity

If fluid circulation is continued during retrieval to clean debris, then hole cleaning is effective, but the differential pressure may activate the cutting member and cause damage

Engineering Contradiction:

Improvedebris cleaning efficiencyVSAvoiddamage from activated cutting member

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The locking mechanism serves as an intermediary that decouples the fluid circulation system from the cutting member extension mechanism. This allows fluid to continue circulating for debris cleaning while the lock prevents the differential pressure from activating the cutting member, resolving the contradiction between cleaning efficiency and damage prevention.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The tool is segmented into independent functional systems: the fluid circulation system for cleaning and the locking mechanism for cutting member control. This segmentation allows fluid circulation to continue for effective hole cleaning while the locking mechanism independently prevents cutting member extension, eliminating the risk of damage during simultaneous operations.

Inventive Principle:

Principle #1Segmentation

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

The cam member lock ensures the cutting member remains retracted during retrieval, preventing damage to the casing or the tool, allowing for safe and effective hole cleaning without stopping fluid circulation.

Implementation Method 1

The lock may be configurable to create a mechanical interference or lock between a part of the cam member and a part of the body

Methodology Applied

Scientific EffectMechanical interference: Mechanical Force

Implementation Method 2

a hydraulically actuated cam member

Methodology Applied

Scientific EffectHydraulic pressure: Pressure Increase

Data Source

PatentUS8973680B2Lockable reamer

Publication Date: 2015.03.10 GRANT PRIDECO LP

AI summary

A downhole tool comprises a body, an extendable cutting member operable to cooperate with a hydraulically actuated cam member, and a cam member lock. The lock is configurable to be activated downhole to restrict movement of the cam member relative to the body and prevent extension of the cutting member.