Portable Mast Assembly for Offshore Well Casing Removal
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Solution Overview
Problem
The existing methods for plugging and abandoning (P & A) oil and gas wells are inefficient and labor-intensive, particularly in removing tubular casing due to the difficulty in cutting and lifting heavy casing sections with existing tools, which often require manual alignment of holes and extensive force, leading to prolonged operation times and potential misalignment issues.
Innovation Solution
A portable, horizontally oriented skid with a vertically oriented, extendable and retractable mast assembly that supports a power swivel and crane, allowing for simultaneous drilling from both sides and enabling the use of hydraulic rams and pivotal swivel cranes to facilitate the removal and milling of well casing strings, cement drilling, and plug setting/pulling operations without the need for extensive setup or alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If manual alignment of holes and extensive force are used to remove tubular casing, then the operation can be completed with simple tools, but the operation time is prolonged and misalignment issues occur
Solution Approach 1:
The device is divided into functional modules: a frame assembly, a mast assembly with independent vertical movement, a cutting tool with rotational capability, and a lifting device. This segmentation allows each component to perform its specific function efficiently while reducing overall system complexity.
Solution Approach 2:
The cutting tool and lifting device are integrated into a single apparatus, allowing simultaneous cutting and lifting operations. The mast assembly combines vertical traversal capability with support for both cutting and lifting functions, reducing the need for multiple separate tools and manual alignment steps.
2Manufacturing precision
If existing tools are used to cut and lift heavy casing sections, then equipment cost is reduced, but alignment precision deteriorates and operation efficiency decreases
Solution Approach 1:
The mast assembly is designed to be vertically traversable along the wellhead, allowing dynamic positioning at different heights. The cutting tool can rotate around the casing, providing dynamic cutting capability. This dynamic design enables precise alignment and efficient cutting operations that static tools cannot achieve.
Solution Approach 2:
The mast assembly acts as an intermediary between the frame assembly and the cutting/lifting tools. It provides the necessary vertical movement and positioning capability, mediating between the fixed frame and the movable tools to achieve precise alignment and efficient operation.
3Ease of operation
If manual alignment and extensive force application are required, then simple equipment can be used, but labor intensity and operation time increase significantly
Solution Approach 1:
The device performs alignment and cutting operations automatically through its mechanical design. The vertically traversable mast and rotatable cutting tool self-align with the casing through guided movement, eliminating the need for manual alignment by operators. The integrated lifting mechanism automatically applies force to raise cut sections without manual intervention.
Solution Approach 2:
Manual mechanical alignment operations are replaced by the mechanically guided traversal and rotation mechanisms. Instead of operators manually positioning tools and aligning holes, the patent uses a vertically traversable mast with a rotatable cutting tool that automatically achieves proper positioning through its degree of freedom mechanisms.
4Force
If heavy tubular casing is removed in sections, then lifting capacity requirements are reduced, but the number of operations and total time required increases
Solution Approach 1:
The lifting device is designed to handle multiple functions: lifting cut casing sections, supporting the weight of tubular strings during removal, and potentially assisting with other well intervention operations. This multi-functionality allows the same apparatus to efficiently handle various lifting scenarios without requiring additional equipment for each operation.
Solution Approach 2:
The device enables continuous cutting and lifting operations through its vertically traversable mast and rotatable cutting tool. As the casing is cut section by section, the mast can continuously move to new positions and the cutting tool can immediately begin the next cut without repositioning the entire apparatus, maintaining continuous useful action throughout the removal process.
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 solution significantly reduces the time and effort required for P & A operations by enabling efficient cutting and lifting of casing sections with improved alignment and force application, enhancing the speed and certainty of the process while accommodating limited offshore spaces.
Implementation Method 1
The mast assembly can be extended and retracted by a hydraulic ram
Implementation Method 2
The cutting tool is supported on the surface and rotated by a rotary swivel
Implementation Method 3
A lifting device is then attached to the inner most tubular... The production tubular is then lifted to a desired length
Data Source
AI summary
A portable mast assembly is comprised of a skid assembly having a horizontally oriented frame having longitudinally extending support surfaces and a mast assembly having at least two vertically extending column assemblies that are supported upon one or more longitudinally extending mast supports. A means for moving the one or more mast supports along the extending support surfaces of the frame is provided.