BOP Guide Spool for Tubular Buckling Prevention
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Solution Overview
Problem
Tubulars are prone to buckling during snubbing operations in live wells due to compressive forces exceeding the tolerance of the annular preventer, especially when well pressures exceed the annular preventer's capacity, leading to potential ejection and buckling within the BOP.
Innovation Solution
A guide assembly is introduced to provide lateral support to the tubular by positioning guide posts between the upper and lower pipe rams, with the guide posts being movable through a guide spool aperture to limit lateral displacement and secure inwardly within the BOP, creating a gap of 0-60% of the tubular's outer diameter to minimize buckling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the annular preventer is used to contain well pressure, then the pressure boundary is maintained, but the tubular is prone to buckling under compressive loads during snubbing operations
Solution Approach 1:
The guide assembly acts as an intermediary structure between the tubular and the BOP encasement. It provides lateral support to the tubular during snubbing operations, preventing buckling while allowing the annular preventer to maintain the pressure boundary. The guide assembly mediates the mechanical interaction, distributing compressive loads and preventing direct contact between the tubular and the BOP walls that would cause buckling.
2Adaptability or versatility
If the tubular is made flexible to navigate the wellbore, then it can navigate curved wellpaths, but it may buckle under compressive loads during snubbing
Solution Approach 1:
The guide assembly introduces a new spatial dimension for support by extending radially inward from the BOP encasement walls toward the center. This creates a three-dimensional support structure that provides lateral stability to the tubular without restricting its flexibility for wellbore navigation. The guide posts positioned at multiple radial locations create a stabilizing envelope that prevents buckling while allowing the tubular to maintain its flexible nature.
3Stability of the object's composition
If the inner diameter of the BOP encasement is reduced to minimize lateral gap, then lateral support is improved, but the tubular joint cannot pass through the BOP
Solution Approach 1:
The guide assembly is segmented into multiple guide posts distributed around the circumference of the BOP encasement. This segmentation allows the structure to provide continuous lateral support while maintaining sufficient clearance for the tubular joint to pass through. The spaced arrangement of guide posts creates multiple support points that collectively stabilize the tubular without forming a continuous barrier that would block joint passage.
4Stability of the object's composition
If guide posts are positioned close to the tubular to minimize lateral displacement, then buckling is prevented, but the guide assembly complexity increases
Solution Approach 1:
The guide assembly is designed as a universal support structure that serves multiple functions: providing lateral support to prevent buckling, guiding the tubular through the BOP, and distributing compressive loads. The guide posts are positioned to provide effective lateral support at critical locations without requiring excessive numbers of posts or complex positioning mechanisms, achieving stability with a relatively simple structure.
Data Source
AI summary
A tubular guide assembly provides lateral support to a tubular extending through a BOP. The inner diameter of the BOP encasement is larger than the joint diameter. The assembly has a guide spool with a central bore extending therethrough along a longitudinal axis, wherein the diameter of the guide spool central bore is greater than the joint diameter of the tubular. At least two guide spool apertures extend radially inwardly through a wall of the guide spool to the central bore. A guide post for each guide spool aperture is movable through the respective guide spool aperture into the guide spool central bore to limit lateral displacement of a tubular extending therethrough. A method for providing lateral support to a tubular extending through a BOP during a snubbing operation uses their guide assembly.