Magnet Assembly for Catching Metal Objects in Wellbores
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Solution Overview
Problem
Conventional methods fail to effectively prevent small metal objects from entering subterranean wellbores, causing disruptions to downhole equipment and operations, and are costly and time-consuming to retrieve, as they often require draining and retesting of blowout preventer assemblies.
Innovation Solution
A magnetic field is generated using a magnet assembly placed between the rig floor and the wellhead, specifically near the bell nipple or riser assembly, to catch falling metal objects and debris, allowing for easy retrieval and preventing them from entering the wellbore.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fishing tools are used to retrieve small metal objects from wellbore, then retrieval is possible, but the process is time-consuming and costly requiring draining and retesting of blowout preventer assemblies
Solution Approach 1:
The magnetic field is activated before objects can fall into the wellbore, creating a protective barrier in advance. This preliminary action prevents the need for subsequent retrieval operations, eliminating the time-consuming process of draining and retesting blowout preventer assemblies.
Solution Approach 2:
A magnetic field serves as an intermediary between the blowout preventer assembly and falling metal objects. The magnetic field intercepts and holds metal objects before they can enter the wellbore, preventing direct contact between objects and the wellbore system.
2Ease of operation
If blowout preventer assembly is drained for object retrieval, then objects can be accessed, but operational downtime increases and retesting is required
Solution Approach 1:
The magnetic field acts as an intermediary that makes objects accessible without draining the assembly. Objects are captured and held by the magnetic field outside the wellbore, allowing retrieval while the assembly remains pressurized and operational.
Solution Approach 2:
The magnetic field is positioned and activated in advance to intercept objects before they enter the wellbore. This preliminary positioning allows objects to be caught and retrieved without the need to drain the assembly, maintaining operational continuity.
3Reliability
If small metal objects enter wellbore, then they are difficult to retrieve, but they cause significant disruption to downhole equipment and operations
Solution Approach 1:
The magnetic field serves as an intermediary that captures small metal objects before they can cause damage to downhole equipment. By intercepting objects in the annular space, the magnetic field prevents objects from entering the wellbore, thereby protecting equipment and simplifying the retrieval process.
Solution Approach 2:
The patent replaces complex mechanical retrieval systems with a magnetic field-based capture system. Instead of using fishing tools that require draining and complex operations, the magnetic field passively captures objects through magnetic attraction, significantly simplifying the retrieval 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
The magnetic field effectively captures small metal objects and debris, preventing them from entering the wellbore and allowing for efficient removal, reducing operational disruptions and costs associated with retrieval processes.
Implementation Method 1
A magnetic field is generated using a magnet assembly placed between the rig floor and the wellhead
Implementation Method 2
the use of magnetic field(s) to catch unwanted objects within a wellbore
Data Source
AI summary
A magnet assembly having selectively removable magnet members can be attached to, or placed in the vicinity of, a conventional bell nipple or riser on a drilling rig to generate a magnetic field within a wellbore. The magnetic field catches falling metal objects and prevents such objects from passing beyond the magnet assembly and entering subterranean portions of a wellbore. Hatch doors are provided for easy access to inner portions of the magnet assembly.