Circumferential Cam Casing Running Tool Engagement

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional casing running tools face challenges in maintaining sufficient engagement with casing or liner strings, especially when there is limited weight suspended, leading to issues with power loss and failure to grip effectively.

Innovation Solution

The casing running tool incorporates cam structures tapered in both axial and circumferential directions, allowing engagement and disengagement through torque provided by the top-drive, with self-energization by gravity for fail-safe operation, using axial and circumferential ramps for secure interaction with the casing or liner.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a hydraulic system is used to engage and disengage the running tool, then the tool can operate with limited weight suspended, but the system becomes more complex and may fail when power is lost

Engineering Contradiction:

Improveengagement reliabilityVSAvoidhydraulic system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the hydraulic engagement system with a purely mechanical cam-based system. The cam structures with axial and circumferential tapers mechanically translate rotational motion into radial engagement forces, eliminating the need for hydraulic power systems while maintaining reliable engagement and disengagement capabilities.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The cam structures are designed to be self-energizing through their geometric configuration. The axial and circumferential tapers create mechanical advantage that automatically increases engagement force as the cam rotates into position, requiring no external power source and providing fail-safe operation even when power is lost.

Inventive Principle:

Principle #25Self-service

2Device complexity

If conventional engagement mechanisms are used, then the tool structure is simpler, but sufficient engagement grip cannot be maintained when limited weight is suspended

Engineering Contradiction:

Improveengagement mechanism simplicityVSAvoidengagement grip force

Core Design Contradiction:

Device complexityVSForce

Solution Approach 1:

The patent introduces dual-taper cam structures that operate in both axial and circumferential dimensions. The axial taper provides mechanical advantage for force multiplication, while the circumferential taper enables rotational control of engagement. This two-dimensional approach creates sufficient grip force through geometric mechanics rather than relying solely on suspended weight.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The cam structures change the engagement parameters through their tapered geometry. As the cam rotates, the varying taper angles dynamically adjust the radial and axial forces applied to the casing, creating variable engagement force that maintains secure grip regardless of the weight suspended from the tool.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If the running tool relies on suspended weight for engagement, then the mechanism is simpler, but it cannot provide fail-safe operation when power is lost

Engineering Contradiction:

Improveengagement mechanism simplicityVSAvoidfail-safe operation

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent converts the potential harm of power loss into a benefit by designing a mechanical system that actually improves reliability when power is unavailable. The cam-based mechanical advantage system requires less force to maintain engagement than active hydraulic systems, making it inherently more reliable in power-loss scenarios while maintaining simplicity.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 solution ensures reliable engagement and disengagement of the casing running tool with the casing or liner, providing a fail-safe mechanism that maintains grip even in the absence of power, using the weight of the casing string and torque from the top-drive for effective operation.

Implementation Method 1

cam structures tapered in both axial and circumferential directions, allowing engagement and disengagement through torque provided by the top-drive

Methodology Applied

Scientific EffectMechanical Advantage: Mechanical Advantage

Implementation Method 2

self-energization by gravity for fail-safe operation, using the weight of the casing string

Methodology Applied

Scientific EffectGravitation: Gravitation

Data Source

PatentUS9057234B2Circumferential cams for mechanical case running tool

Publication Date: 2015.06.16 NABORS DRILLING TECHNOLOGIES USA INC

AI summary

A casing running tool is provided having both axial and circumferentially tapered elements. In certain embodiments, the casing running tool comprises cam structures that are circumferentially tapered so as to allow an applied torque to engage and disengage the casing running tool with a casing or liner. In embodiments, the circumferential taper of the cam structures allows a mandrel or rollers disposed between the mandrel and cam structures to apply radial force to corresponding shoe structures which in turn engage or disengage the casing or liner. The cam structures may also exhibit an axial taper to allow for a self-energized fail-sage operation of the casing running tool.