Waveform Profile Stop Collar for Restricted Wellbore Diameters
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Solution Overview
Problem
Conventional stop collars for wellbore tubulars often catch and interfere with wellbore walls at restricted diameter locations, require fasteners that can damage the casing string, and need custom manufacturing for a suitable fit, leading to a need for low-profile stop collars that can accommodate variances in casing string diameters without damaging the surface.
Innovation Solution
A stop collar design featuring an inner ring with a waveform profile and an outer ring that compresses the inner ring to securely attach to the casing string, allowing for deformation to fit through restricted diameters and preventing damage, with a friction-enhancing coating to prevent scratching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional stop collars are mounted on the casing string, then longitudinal movement of centralizers is restricted, but the stop collars catch and interfere with wellbore walls at restricted diameter locations
Solution Approach 1:
The stop collar incorporates a resilient element that allows the collar to dynamically adjust its diameter. The collar can expand to engage and restrict longitudinal movement of the centralizer, then compress to pass through restricted diameter locations in the wellbore, and spring back to its expanded state afterward. This dynamic behavior resolves the contradiction between maintaining centralizer position stability and enabling passage through constrictions.
Solution Approach 2:
The stop collar changes its physical parameter (diameter) by utilizing the elastic properties of the resilient element. The collar transitions between an expanded state with a larger diameter for engaging the centralizer and restricting its movement, and a compressed state with a smaller diameter for passing through restricted wellbore sections. This parameter change allows the stop collar to fulfill both conflicting requirements.
2Reliability
If fasteners are used to attach stop collars to the casing string, then secure attachment is achieved, but the fasteners scratch and damage the outer surface of the casing string
Solution Approach 1:
The stop collar employs a resilient element that acts as a flexible shell to attach to the casing string. This flexible element wraps around the casing and secures the stop collar through friction and elastic retention, eliminating the need for rigid fasteners like screws or clips that would scratch and damage the casing string's outer surface. The flexible nature of the resilient element ensures secure attachment without harmful contact.
3Manufacturing precision
If conventional stop collars are designed for a specific casing diameter, then precise fit is achieved, but custom manufacturing is required for each casing string section
Solution Approach 1:
The resilient element in the stop collar allows the collar's inner diameter to change and adapt to different casing string diameters. Instead of manufacturing custom stop collars for each specific casing size, a single design with a resilient element can be used universally, as the element will elastically deform to match the outer diameter of the casing string it is attached to. This eliminates custom manufacturing requirements while maintaining precise fit.
Solution Approach 2:
The stop collar design with a resilient element achieves multi-functionality by being able to attach to and fit various casing string diameters. The resilient element allows the same stop collar design to accommodate different casing sizes through elastic deformation, making the stop collar universal rather than requiring custom-manufactured variants for each casing specification.
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 stop collar effectively restricts longitudinal movement of centralizers while minimizing interference with wellbore walls and accommodating manufacturing variances, ensuring a secure fit without damaging the casing string, thus facilitating smooth operation through restricted diameter locations.
Implementation Method 1
The waveform profile includes a peak and a base. The stop collar includes an outer ring configured to be disposed around the inner ring and configured to compress the inner ring
Data Source
AI summary
A stop collar for a tubular includes an inner ring configured to engage the tubular and having a waveform profile. The waveform profile includes a peak and a base. The stop collar includes an outer ring configured to be disposed around the inner ring and configured to compress the inner ring. A method for assembling a stop collar for a centralizer on a tubular includes positioning an inner ring around the tubular, the inner ring including a profile and compressing the profile against the tubular by disposing an outer ring around the inner ring.