Wellbore Tubular Connector With Multi-Ramp Slip Grip Under Torque

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Solution Overview

Problem

Existing connectors for coiled tubing in the oil and gas industry face limitations in axial load capacity and are prone to releasing due to torque, especially when used with downhole motors, leading to inefficiencies in tool deployment and retrieval.

Innovation Solution

A connector design featuring a tubular housing with multiple elongate ramp arrays and channels, combined with a slip body having corresponding ramp arrays and channels, allows for a secure grip over a longer length and includes a locking mechanism to prevent inadvertent release under torque conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a single ramp face connector is used, then the device complexity is low, but the axial load capacity is limited

Engineering Contradiction:
Improveaxial load capacityVSAvoidconnector structure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The connector is divided into multiple ramp arrays (typically three) arranged circumferentially around the central axis, with each ramp array containing multiple inclined ramps. This segmentation allows the axial load to be distributed across multiple independent load paths, significantly increasing the overall axial load capacity while maintaining a relatively simple modular structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The design transitions from a single-ramp configuration to a multi-ramp array configuration arranged in three-dimensional space around the central axis. The ramps are positioned at different angular positions and heights, creating a three-dimensional load distribution system that increases strength without proportionally increasing complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If a conventional connector is used, then the ease of operation is simple, but the reliability under torque conditions is poor

Engineering Contradiction:
Improveresistance to inadvertent release under torqueVSAvoidassembly and retrieval simplicity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The connector design preemptively counteracts the harmful effect of torque-induced release by using multiple ramp arrays that engage the tubular at multiple circumferential positions. This preliminary anti-action prevents the tubular from rotating or disengaging under torque loads, particularly when used with downhole motors, without requiring complex additional locking mechanisms.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The slip body is pre-configured with multiple ramp arrays that are positioned to engage the outer surface of the tubular before torque is applied. This preliminary engagement creates multiple friction and mechanical interlocking points that prevent inadvertent release, ensuring reliability is established before operational stresses occur.

Inventive Principle:
Principle #10Preliminary action

3Strength

If the slip length is increased to improve grip, then the axial load capacity improves, but the device complexity increases

Engineering Contradiction:
Improveaxial load capacityVSAvoidramp assembly complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The slip body is segmented into multiple ramp arrays arranged circumferentially, with each array containing multiple ramps distributed along the axial length. This segmentation allows the total slip length to be effectively distributed across multiple parallel engagement zones, increasing axial load capacity without requiring a single excessively long ramp structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple ramp arrays are merged into a single integrated slip body structure, combining their individual gripping capabilities into a unified system. The cumulative effect of multiple ramps across multiple arrays provides enhanced axial load capacity equivalent to a much longer single ramp, while maintaining compact dimensions and manageable complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 connector provides a more secure grip and improved axial load capacity, reducing the risk of coiled tubing collapse and release due to torque, enhancing the efficiency of tool deployment and retrieval operations.

Implementation Method 1

The slip is urged inwardly by travelling up an inclined ramp disposed in the housing, moving radially inwardly toward the coiled tubing so that the slip teeth bite into the tubing. This secures the connector to the tubing

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3973135B1A connector for wellbore tubulars
Publication Date: 2023.10.25 WELL ENG TECH FZCO

AI summary

A connector (10) for connecting a first wellbore tubular (12) to a second wellbore tubular (14) comprises a tubular housing (16) connectable to the second tubular and comprising an internal surface (20) facing an internal bore (18), and a ramp assembly (22) arranged around the surface. The housing ramp assembly comprises a plurality of elongate ramp arrays (36) each comprising ramps (38) inclined towards the bore, and a plurality of elongate channels (40) arranged so that ramp arrays which are adjacent are separated by a channel. The connector also comprises a slip body (24) which is insertable into the internal bore comprising an internal surface (28) which faces an internal passage (26) and which comprises at least one slip tooth (30) for engaging the first tubular, an external surface (32) and a ramp assembly (34) arranged around the external surface. The slip body ramp assembly comprises a plurality of elongate ramp arrays (42) each comprising a plurality of ramps (44) which are inclined away from the body and which cooperate with the housing ramp arrays to cause the slip tooth to grip the first tubular. The slip body ramp assembly also comprises a plurality of elongate channels (46) which are arranged so that ramp arrays which are adjacent are separated by a channel. The ramp arrays of the slip body are each alignable with a respective channel of the tubular housing, so that the slip body can be inserted into the tubular housing. The slip body is rotatable within the tubular housing, so that the ramp arrays of the slip body can each be brought into alignment with a respective ramp array of the tubular housing.