Tubular Gripping Device Threaded Mandrel Axial Load
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Solution Overview
Problem
Existing tubular gripping devices for wellbore operations often damage the threads of oilfield tubulars due to close tolerance thread forms, and they may not efficiently transmit torque in both directions without requiring additional tools for tripping out tubular strings.
Innovation Solution
A tubular gripping device featuring a mandrel with a threaded interval and a force generating assembly, including a cam assembly or hydraulic system, that applies axial load to engage and manipulate tubulars without damaging their threads, allowing for rotational and axial movement while preventing axial separation during torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a tubular gripping device with slips is used to engage and manipulate tubulars, then the device can securely grip and move tubulars during wellbore operations, but the slips may mark or damage the wall of the tubular
Solution Approach 1:
The patent introduces a threaded engagement mechanism as an intermediary between the gripping device and the tubular. Instead of direct contact through slips, the threaded interval on the mandrel engages with the threaded box end of the tubular, providing secure grip without surface marking. The force generating assembly applies load through this threaded intermediary, eliminating the harmful slip contact while maintaining reliable grip.
2Object-affected harmful factors
If a threaded engagement mechanism is used to avoid slip damage, then the tubular surface is protected, but the device complexity increases due to additional components like force generating assemblies
Solution Approach 1:
The patent merges the threaded engagement function directly into the mandrel structure, integrating the force generating assembly with the mandrel body. The threaded interval is formed on the mandrel itself rather than being a separate component, and the force generating assembly utilizes the mandrel's structural features. This integration reduces the number of separate parts while maintaining the protected engagement mechanism.
Solution Approach 2:
The mandrel serves multiple functions: it provides the threaded engagement interface, supports the force generating assembly, transmits rotational and axial loads, and positions the threaded interval relative to the tubular. By making the mandrel a multi-functional component, the patent reduces overall device complexity while achieving the threaded engagement benefit.
3Manufacturing precision
If close tolerance thread forms are used in the gripping device, then the engagement precision is improved, but the threads of the tubular are damaged during engagement
Solution Approach 1:
The patent applies partial action by using a threaded engagement mechanism that engages only the threaded box end of the tubular rather than requiring close tolerance engagement along the entire tubular surface. The force generating assembly applies axial load selectively through the threaded interval, providing sufficient engagement precision without the excessive contact pressure that would damage the tubular threads. This localized engagement approach maintains precision while avoiding thread damage.
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 device securely grips and manipulates tubulars without damaging their threads, enabling efficient torque transmission in both directions, reducing the need for additional tools during wellbore operations.
Implementation Method 1
a cam assembly or hydraulic system, that applies axial load to engage and manipulate tubulars
Implementation Method 2
a cam assembly or hydraulic system, that applies axial load to engage and manipulate tubulars
Implementation Method 3
a mandrel with a threaded interval and a force generating assembly, including a cam assembly or hydraulic system, that applies axial load to engage and manipulate tubulars
Data Source
AI summary
A device for handling well pipe includes a mandrel including an upper end, a lower end and a long axis extending between through the upper end and the lower end. The mandrel secures to a top drive of a drilling rig. A threaded collar is located on an outer surface of the mandrel to loosely engage threads of a well pipe. An annular force generating assembly is carried on the mandrel and positioned between the upper end and the threaded collar. The force generating assembly applies a load to an upper end of the well pipe along the long axis, enabling torque to be transmitted between the threaded collar and the well pipe. The force generating assembly may be cams or a hydraulic piston.