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Sealed and hydrostatically lockable retrievable mwd landing system

a technology of hydrostatic lock and landing system, which is applied in the field of mule shoe assembly, can solve the problems of abrasive materials such as drilling fines, sand and other detritus frequently entering and cannot provide circumferential seals within the mule shoe assembly of such designs, so as to avoid expensive “tripping out” operations and prolong the life of the mule sho

Inactive Publication Date: 2014-02-20
PACESETTER DIRECTIONAL DRILLING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention is a mule shoe assembly for use in abrasive downhole environments. It is designed to improve its resistance to wear compared to prior art mule shoe assemblies by using mating "halves". The assembly includes a directional tool member and an outer mule shoe member with half-moon members that are sealed to protect the landing area from abrasive substances. The seals and the particular configuration for landing the direction tool and housing within the mule shoe greatly reduces sand and / or drilling fines from coming into contact with the landing area, namely with the half-moon members of the mule shoe and directional tool housing. This results in a longer life for the mule shoe and avoids expensive "tripping out" operations to replace worn mule shoe assemblies.

Problems solved by technology

Disadvantageously and problematically with such prior art mule shoe assemblies, circumferential seals are not capable of being provided within the mule shoe assembly of such designs due to the arcuate camming surfaces employed which extend longitudinally of the outer mule shoe and the directional measurement tool.
As a result, abrasive materials such as drilling fines, sand and other detritus from drilling operations frequently enters the mule shoe assembly during drilling.
Such vibrational movement (albeit initially small) due to the large numbers of vibration cycles needed to transmit ever increasing quantities of data to surface, due to the highly abrasive nature of drilling fines and fluids containing such fines or sand, causes rapid and extensive wear of each of the two components at the point of coupling Such wear leads to loss of the fixed angular orientation of the directional measurement tool relative to the outer mule shoe member, and thus invariably leads to loss in accuracy of the measurement tool orientation and thus loss of ability to sense the direction of drilling of the drill bit.
In addition, such imparted vibration and exposure to abrasive materials causes extensive wear of the two components such that directional sensor orientation is lost, which directly results in the loss of the ability to “steer” the drilling bit from surface by rotating the drill string (and bit attached thereto) during directional drilling operations.
Such frequent “tripping out” of the directional drilling drill string greatly slows the drilling process, and greatly adds to the expense of drilling.

Method used

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  • Sealed and hydrostatically lockable retrievable mwd landing system
  • Sealed and hydrostatically lockable retrievable mwd landing system
  • Sealed and hydrostatically lockable retrievable mwd landing system

Examples

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first embodiment

[0052]In the present invention, various views of which are shown in FIGS. 4-7, mule shoe assembly 100 comprises an outer mule shoe member 120 and a tool housing 160 for containing a direction-indicating tool therewithin (not shown). Outer mule shoe member 120 is provided with a longitudinal bore 280, a portion of which is cylindrical. A half-moon member 124, one embodiment of which is best shown in FIG. 4 in perspective view, is fixedly secured, typically by welding, to a circumferential portion 125 of longitudinal bore 280 about at least a portion 126 of a circumference of bore 280.

[0053]Directional tool housing 160, as shown in FIG. 4, is typically hollow and is adapted for containing therein a direction-indicating tool (not shown), such tool being retained therein via a threaded end cap member 130, which end cap member 130, as further explained below, possesses at least one circumferential seal in the form of at least one ‘o’ ring 300 extending about the circumference thereof.

[00...

third embodiment

[0065]FIG. 9 shows the mule shoe assembly 100 of the present invention, which is further adapted to improve the ease by which fluid may be allowed to egress landed areas 400, 401 when the directional tool member 160 is inserted within mule shoe member 120, which uses two boreholes 501, each adapted to contain an associated check valve 500, and which two check valves 500 together operate to allow egress of all fluid such as air from within said mule shoe assembly 100 when said directional tool member 160 and associated half-moon member 134 matingly engage half-moon member 124 within mule shoe member 120. Again, due to the elimination of a circular collar 801 (see FIG. 7) on half moon member 124, fluid can effectively egress from within interstitial areas 400, 401 via respective check valves 500, and no bore 700 is needed within either of half moon members 124, 134.

fourth embodiment

[0066]FIG. 10 shows a separate, fourth embodiment of the mule shoe assembly 100 of the present invention which eliminates the borehole(s) 501 and ball-style check valve(s) 500, and instead utilizes, in the embodiment shown, an annular “flapper” style seal member 308 which effects a seal between distal end 161 of directional tool member 160 and mule shoe member 120 at one end 121 of mule shoe assembly 100. An externally-threaded nut 311 may be used to retain seal member 308 within outer mule shoe member 120, as shown in FIG. 10.

[0067]Advantageously, flapper style seal member 308 is of a resiliently flexible material such as synthetic rubber, and allows egress of fluid from interstitial areas 400, 401 during insertion of directional tool member 160 within mule shoe member 120, but which prevents ingress of fluid, including and in particular drilling fluid containing abrasive drill tailings or sand, into interstitial landed area 400, 401. A small borehole 603 may optionally be provided...

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PUM

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Abstract

A sealed mule shoe assembly for use in directional drilling, comprising an outer mule shoe and an inner housing for containing a directional measurement tool which is slidably insertable in the outer mule shoe. The mule shoe assembly advantageously has half-moon mating surfaces which advantageously allow use circumferential seals to thereby prevent ingress of abrasive materials into the landing area between the outer mule shoe and the inner housing, thereby greatly prolonging the life of the mule shoe assembly. Such seals further make use of hydrostatic forces downhole which cause locking landed engagement of the inner tool within the outer mule shoe. Cup seals or a check valve are used to allow escape of fluid when the inner tool is inserted within the outer mule shoe, and similarly prevent ingress of abrasive fluids and drill cuttings into the area of landed engagement.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a component of a drill string for use in directionally drilling of oil wells, and more particularly to an improved mule shoe assembly for downhole MWD (“measurement while drilling”) operations as part of a drill string, having an outer mule shoe member which receives therein a directional measurement tool having electronic ensing components and / or mud pulser units therein for sensing and transmitting, respectively, directional drilling data from downhole to surface during drilling. Due to its unique configuration the mule shoe assembly of the present invention is able to make use of seals which seal the area of mating engagement to thereby resist ingress of abrasive substances such as sand which otherwise disadvantageously causes extreme wear and ultimate loss of functionality of the mule shoe assembly, and by such configuration is further adapted to use hydrostatic forces to better retain the two components together.BACKG...

Claims

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Application Information

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IPC IPC(8): E21B47/022
CPCE21B47/017
Inventor SCHMIDT, AXELAASEN, DUSTIN
Owner PACESETTER DIRECTIONAL DRILLING