Riser Magnet Assembly for Catching Falling Ferrous Objects
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Solution Overview
Problem
Small ferrous metal objects entering a wellbore can disrupt downhole equipment and operations, and existing methods for retrieval are costly and time-consuming, especially since conventional fishing tools are ineffective for small, irregularly shaped objects.
Innovation Solution
A magnetic field is generated and positioned between the rig floor and the wellhead within a marine riser assembly to catch falling ferrous objects, preventing them from entering the subterranean wellbore and allowing for easy removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional fishing tools are used to retrieve small metal objects from a wellbore, then retrieval may be achieved for larger objects, but small, irregularly shaped objects cannot be effectively grasped or removed
Solution Approach 1:
The patent replaces the mechanical grasping system of conventional fishing tools with a magnetic field-based retrieval system. Magnets are deployed into the wellbore to attract and hold ferrous metal objects, eliminating the need for mechanical contact and grasping. This allows effective retrieval of small, irregularly shaped objects that cannot be grasped by traditional mechanical means.
Solution Approach 2:
The invention changes the physical parameter of retrieval from mechanical force application to magnetic field interaction. By using magnetic attraction rather than mechanical grasping, the system can effectively retrieve small ferrous objects regardless of their shape or size, overcoming the limitations of conventional fishing tools.
2Object-affected harmful factors
If blind rams in a blowout preventer are closed to block objects from entering the wellbore, then object entry is prevented, but the object must still be retrieved from the top of the blind rams through a complex and time-consuming process
Solution Approach 1:
The patent introduces magnets as an intermediary mechanism between the rig floor and the wellbore. Instead of closing blind rams and then retrieving objects through complex procedures, magnets are deployed to capture objects in the annulus space, allowing for simpler and faster retrieval by simply pulling the magnets out with captured objects attached.
Solution Approach 2:
The invention performs preliminary action by deploying magnets into the wellbore before objects can fall in. The magnets are positioned in advance to create a magnetic barrier that attracts and holds any ferrous objects that may fall, preventing them from reaching the blind rams and enabling quick retrieval without the need to open and close the preventer.
3Productivity
If small ferrous metal objects are allowed to enter the wellbore, then operational continuity is maintained, but downhole equipment can be disrupted or destroyed
Solution Approach 1:
The patent applies preliminary anti-action by deploying magnets to counteract the potential harmful effect of falling objects before they can reach downhole equipment. The magnetic field creates a protective barrier that attracts and holds ferrous objects in the annulus space, preventing them from entering the wellbore and disrupting equipment, thus maintaining both productivity and reliability.
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 magnetic field effectively prevents small metal objects from entering the wellbore, reducing operational disruptions and costs associated with retrieval, while maintaining fluid pressure integrity and allowing for safe, efficient removal of captured objects.
Implementation Method 1
A magnet assembly comprises at least one magnet and is disposed on, around, or as an integral part of a wellbore
Implementation Method 2
The magnetic field is used to catch falling metal and/or magnetic objects
Data Source
AI summary
A riser magnet assembly having selectively removable magnet members can be incorporated within a riser assembly of a drilling rig to generate a magnetic field within a central bore of the riser assembly. The magnetic field catches falling metal objects and prevents such objects from passing beyond the magnet assembly and entering subsea equipment or subterranean portions of a wellbore without sacrificing fluid pressure integrity of the riser assembly. At least one stripper door is provided for easy access to inner portions of the magnet assembly.