US2196528A - Knuckle anchor for whipstocks - Google Patents

Description

' April 9, 1940.

J. p. HUGHES Kwam: ANCHOR Fon w'mPsTocxs Filed oct. 2s'. 195'.'

' tion is considered in connection with the accom- V Patented Apr. 9, 1940 UNITED STATES 2.196.528 xNUoxLE ANCHOR ron wnrrs'rooxs James D. Hughes,

half to Eastman of California and one Dallas, Tex., assigner of one- Oil Well Survey Corporation -half to Eastman Oil Well Survey Company of Delaware Application October 28, 1937, Serial No. 171,464 3 Claims. (Cl. Z55-1) The invention relates to a particular type of whipstock which is capable of being securely anchored in the well bore against rotation but which is also readily removable after the deflecting operation has been performed.

I t is one of the objects of the invention to provide a knuckle joint anchor for a whipstock bottom. y

Another object of the invention is to provide an off center shoe for whipstocks so that when weight is applied to the whipstock the shoe will seatitself due to this applied weight and in this manner anchor the whipstock against rotation.

Still another object of the invention is to provide in combination with a removable whipstock an anchoring device which will be set by applying Weight to the whipstock.

' Another object of the invention is to provide an anchoring device for whipstocks which will tilt the lower end of the whipstockv in the direction in which the deection is to be made so as to increase the angle of deection which may be obtained by the use of thewhipstock.

Other and further objects of the invention will be readily apparent when the following descrippanying drawing wherein:

Fig. l is a front elevation of the whipstock with the partsassembled ready to be lowered into the well bore.

Fig. 2 is an elevation at right angles to Fig. 1 and showing the whipstock being lowered into the well bore preparatory to being set.

Fig. 3 is a section taken on the line 3-3 of Fig. 2.

Fig. 4 is a side elevation of the lower end of the whipstock and illustrating the anchor as being set into the formation.

The whipstock of Fig. 1 is made up of a longitudinal body 2 which may be of any desired length and is usually provided with a concave face 3, which gradually merges with the body of the whipstock until it disappears at the lower end 4 thereof. This concave surface is provided for the purpose of guiding the drill bit 5 in order to deflect the well bore which is indicated generally at 6.

The particular type ofwhipstock here shown is that disclosed in the patent to McVicar, No. 1,970,761, granted August 21, 1934. Whipstocks of this type are provided with a collar I3 at the upper end thereof, which is integral with the body 2 of the whipstock and extends laterally from the upper portion Il of the deiiecting face 3. 'I'he drill stem I2 has the drill bit 5 conbore so that the nected therein in such a manner that the collar I0 is disposed about the drill stem above the bit or about the shank of the bit, so that the whipstock is suspended by the drill bit as the assembly is being lowered into the well. The sus- 5 pended position is shown in Fig. 2. A pin I4 is shown as passing through the collar and into the drill stem in order to secure the whipstock against displacement While it is being moved downwardly into the well bore. because in some instances cavings or a bridge might obstruct the hole and the whipstock might be set inadvertently upon striking such a bridge, so that it is desirable to hold the whipstock in a predetermined position `until it is lowered into 15 the well bore. Another reason for holding the whipstock in a known and predetermined position with respect to the drill stem is that it may be desirable to orient the whipstock into the well deiiecting face 3 will be set in 20 the well bore in a predetermined oriented position so as to cause the deflection in a desired direction.

The lower end or foot of the whipstock is of a particular construction as seen best in Figs. 2, 3 25 and 4, and comprises a shoe 20 which may have tapered faces 2| which merge in a point or blade 22. 'Ihis blade is provided with atongue or shank 23 which is of such a width that it will iit into the space 24, which is formed by the leg 25 30 on the lower end of the whipstock body 2. A pivot pin 26 passes through the legs and the tongue as best seen in Fig. 3, so that the shoe 2li may pivot or tilt with respect to the whipstock body. As seen in Fig. 2, the upper end of the 35 tongue is curved at 21 so that it is confined within the whipstock body as it tilts.

`it will be observed that the pivot pin 23 is of! center or positioned to one side oi' the longitudinal axis of the whipstock and that the blade 40 portion 22 is lprovided with a heel -23 thereon which is on the lower righthand corner. A shoulder 30 is provided on the shoe which is arranged to engage a cooperating shoulder 3| on the whipstock body and these intertting shoul- 45 ders may be provided with teeth 32 thereon.

In operation, as the device approaches the bottom 35 of the well bore 6 the heel 29 of the shoe will engage the bottom 35, but due to the oilcenter arrangement of the 'pivot pin, when 50 weight is applied to the shoe the knuckle construction will permit it to'tilt or kick over to assume the general position shown in Fig. 4 in that the shoe has caused the pivot pin 26 to move to the left and to throw the shoulder 3| against 55 This is necessary 10 the side wall S'Iso that the teeth 32 will bite into the formation. At the same time the heel 28 will bite into the side wall 38 oi' the well bore as the shoe tilts about the pivot pin. The blade 22 of the shoe will, of course, penetrate the bottom 35 o1' the well bore so that there are as a matter of fact three points of anchorage for the whipa stock, all of which tend to prevent it from rotating when the drill bit Sis thereafter rotated; f

Another advantage to be obtained is the fact that after the shoe 20 pivots it will move the lower end of the whipstock to the left as seen in Fig. 4, so that while the deilecting face 3 may be of a .predetermined angle with respect to the longitudinal axis of the whipstock, the whipstock itself will be in this manner tilted so that the angle of deection for the bit 5 will be increased. 'I'his angle can, oi' course, be increased by spudding the whipstock in position to force it a greater distance into the formation and accordingly tilt it a greater amount, or on the other hand the whipstock may be set gently so as to cause little or no tilting.

When the deilecting operation has been performed, of course, the drill bit will have moved downwardly along the deflecting face 3 and into the side wall 37 0i' the formation to initiate the deiiected well bore. When this drilling operation has been completed the drill stem is raised untilthe drill bit moves upwardly into contact with the collar In whereupona pull is exerted upon the whipstock and, readily pivot about the pin 28 so withdrawn from its anchored position.

Broadly the invention contemplates a whipstock which will be anchored automatically merely by applying weight thereto.

What'is claimed is:

1. The combination of a drill stem, drill bit and whipstock, means to carry said whips-teck on said drill stem, a shoe on said whipstock, and an ofl' center pivoti'or said shoe so as to tilt the shoe; to dig into the earth formation at one side ,and the base oi' the bore to anchor said whipstock.

2. A base anchor for whipstocks comprising a shoe portion, a tongue thereon, a pair of spaced legs to receive said tongue, a pivot pin connecting said tongue and legs, said pin being positioned on center with respect to the whipstock.

3. A base anchor ior whipstocks comprising a shoe portion, a tongue thereon, a pair of spaced legs to receive said tongue, a pivot pin connecting said tongue and legs, said pin being positioned off center with respect to the whipstock, and a heel portion on said shoe so as to shift the base of the whipstock as said shoe is set.

JAMES D. HUGHES.

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