MAGNETIC TOOLS FOR OIL WELL DRILLING

Magnetic Tools for Oil Well Drilling

Introduction

This paper relates to a cleaning device designed for use when removing ferrous material from the wellbore and the cleaning assembly comprising multi set of such devices to clean the wellbore and a method for removing iron material from the wellbore. In particular the paper relates to cleaning device comprising at least one magnet is designed to remove the same material from the wellbore.

Discussion

All tools that are offered by various oil and gas service companies have two cylindrical threaded ends and a middle section that carries permanent magnets in the shape of blocks and buttons distributed along the magnetic section. The tool body itself is none magnetic. There could be centralizers installed on the tool to insure the tool is always central in relation to the casing wall surrounding it so that the magnetic force emitted by the magnets is uniform. The centralizers outside diameter are normally equal to the drift inside diameter of the casing or less by a small clearance. There is normally flow channels cut on the outer surface of the centralizer where the fluid and debris passes through. The magnetic section is a smaller diameter to allow for debris build up without getting jammed against the casing inside wall (Tiittanen J. & et al, 2009).

Once the ferrite debris enters the magnet section they will be pulled to the nearest magnet with maximum pull force where the fluid kinetic energy will take care of distributing the debris all over the magnetic section of the tool. a magnet with debris are already attracted and build up on its surface will offer less pull force and the debris will keep travelling with the fluid until there is magnet that has no or less debris build up where the pull force can overcome the fluid kinetic energy (Morgan, n.d.).

There are various types of cleaning devices one of which is generally referred to as the crossed side to clean the casing. Devices of this type usually contain scraper blades designed to clean the inside of the casing or liner to remove relatively large particles or debris from the surface of the tubes. While it is recognized that it is desirable to use such pressure washers to clean the casing or liner but when you remove scraper cleaning of the well casing scraper blades can throw more debris into the wells fluid invalidating the results of previous cleaning operations. Similar difficulties arise when using cleaning other types of devices including those that contain brush or other abrasive surface circulating devices and the like (Weickhmann & et al, n.d.).

To address the shortcomings associated with the use of such devices has been developed the magnetic device for cleaning wells such as described in the patent issued to the applicant of Great Britain number 2350632 which contains some of the magnets. In the application of black metal and the- breaking present in the wellbore are attracted to magnets and are removed from ...