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Downhole Magnetic Retrieval Tool

IP.com Disclosure Number: IPCOM000228539D
Publication Date: 2013-Jun-17
Document File: 3 page(s) / 539K

Publishing Venue

The IP.com Prior Art Database

Abstract

With a new arrangement to position magnets along tool body, debris collect capacity per unit of tool length is maximized, while the required annular flow area between tool and casing ID is still maintained.

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Downhole Magnetic Retrieval Tool

With a new arrangement to position magnets along tool body, debris collect capacity per unit of tool length is maximized, while the required annular flow area between tool and casing ID is still maintained.

As shown in Figure 1, the current magnet tool designs such as U.S.  patent 7,219,724 and patent application US 2011/0285155 are facing the same dilemma that there is a trade-off between maximizing the debris collect capacity and maintaining required flow area in the annular space.  For example, in US2011/0285155 the total number of the ribs holding the magnets needs to be limited such as between each two ribs there is enough space and debris attracted to the magnets will not block off annular flow area.  As a result, the total number of magnets the tool installed and debris collection capacity per unit length of the tool will be limited.  In order to resolve this dilemma, this invention proposes a tool body with ribs to hold magnets similar to that in US2011/0285155.  However the novelty is that the ribs are machined in a helical pattern.  In this way, the body OD can be maximized without the concern of flow area; the total number of magnets can be installed per unit length of tool body is maximized thus debris capacity increases.  As shown in Figures 2 and 3, magnets can be directly installed on the ribs or pre-assembled into a tube and then attached to the ribs.