Wellhead Housing Bore Accommodates Tubular Offset
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Solution Overview
Problem
The installation of a wellhead is hindered by axial misalignment between cemented inner and outer tubulars, preventing the proper installation of the casing hanger and posing challenges in maintaining well integrity.
Innovation Solution
A system involving a long weld neck flange is used to align the central axis of the inner tubular with the wellhead installation stack, which includes welding the flange to the outer tubular and wellhead housing, and incorporating a casing hanger with slips and a seal assembly to secure the inner tubular, thereby correcting the offset without disrupting the cemented tubulars.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional wellhead installation method is used, then the installation process is straightforward when tubulars are aligned, but the installation fails when axial misalignment exists between inner and outer tubulars
Solution Approach 1:
The patent introduces a wellhead housing with a bore that acts as an intermediary component between the misaligned inner and outer tubulars. The bore is specifically designed with sufficient radial clearance to accommodate the offset between tubular central axes, allowing the casing hanger to be installed without requiring precise alignment while maintaining structural integrity and sealing performance
2Manufacturing precision
If remedial work is performed to correct tubular offset, then alignment can be achieved, but time and labor requirements increase significantly
Solution Approach 1:
The wellhead housing is pre-designed and manufactured with a bore that inherently accommodates tubular misalignment through built-in radial clearance. This preliminary design feature eliminates the need for time-consuming remedial alignment work, as the housing is prepared in advance to accept offset tubulars without requiring field corrections or adjustments
3Manufacturing precision
If extensive wellhead modifications are made to correct offset, then alignment can be achieved, but the risk of human error and well abandonment increases
Solution Approach 1:
The wellhead housing serves as a protective intermediary that isolates the misalignment issue from the critical sealing and support functions. By designing the bore with adequate radial clearance, the system accommodates offset tubulars without requiring modifications to the inner tubulars or cement annulus, thereby maintaining well integrity and reducing the risk of human error associated with complex correction procedures
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 method efficiently corrects tubular eccentricity, reduces the time and labor required for remedial work, and maintains well integrity by aligning the tubulars without extensive wellhead modifications, minimizing the risk of human error and well abandonment.
Implementation Method 1
The flange is welded to the outer casing of the outer tubular. The wellhead housing is welded to the flange.
Implementation Method 2
The casing hanger is frictionally attached to the inner tubular within the wellhead housing.
Data Source
AI summary
A system for positioning an inner tubular within an outer tubular. The outer tubular is inserted in a wellbore and has a first central axis. The inner tubular defines an inner passage of the outer tubular and is inserted in a wellbore. The inner tubular has a second central axis that is offset from and parallel to the first central axis. A flange is attached at an uphole end of the outer tubular and encircles an outer circumference of the inner tubular. The flange has a third central axis that is in-line with the second central axis. A wellhead housing is positioned at an uphole end of the flange and encircles the outer circumference of the inner tubular. A casing hanger is positioned within the wellhead housing and has an interference with the wellhead housing. The casing hanger is frictionally attached to the inner tubular.