US2357330A - Whipstock assembly - Google Patents

Description

#Patented Sept. 5, 1944 UNITED STATES PATENT OFFICE WmPsfrocK ASSEMBLY Robert S. Hye'r, Houston,;Tex., assignor to Sperry- Sun Well Surveying Company, Philadelphia, Pa., a corporation of Delaware l Y Application April 2, 1940,'s3ena1 No. 327,404

4 claims. (c1. zee-'1.6)

This invention relates to a Whipstock assembly, and more Aparticularly to the connection of a whipstock to a drill stem..

At the present time it is customary to lower a whipstock into a hole and locate it in position by means of a drill stem to the lower portion of which, generally above a-bit, it is secured by means of a pin adapted to be sheared off when the whipstock is to be freed from the drill stem.

'I'he use of the conventional shear pin is at- :tendant with hazard which may cause delay and .considerable expense. First, if the Whipstock hits an obstruction in the holeas it is being flowered, it is not uncommon for the weight of the drill ,pipe above the whipstock to shear the --pin before the presence of an obstruction is indi- -@cated-on the usual weight indicator. `In such pase, the orientation of the whipstock may be lost if it was oriented by drill stem orientation, and,

hole, the shear pin replaced, and the orientation started all over again. In the event that the bit is larger than the collar at the top of the Whipstock, the shearing of the pin while going into the hole will not result in the loss of the whipstock, because it can be withdrawn by engagement with the bit. However, with other types of whipstocks and bit combinations` in which the bit may pass through the collar of the whipstock, the whipstock will remain inthe hole, possibly being dislodged from the obstruction and dropping to the bottom,`so that a iishing job must bev undertaken.

It is the broad object of the present invention to avoid the arising of such diiliculties in the great majority of cases. This and otherY objects of the invention, particularly'relating to details, will become apparent from the following description, read in conjunction with the accompanying drawing, in which: Figure 1 is a vertical section through the lower portion of a drill stem and the upper portion of a. whipstock illustrating an improved mode of connection; and

Figure 2 is a section taken on the plane indicated at 2-2 in Figure 1.

A whipstock is indicated at 2 provided, at its upper end, with a collar 4, through which extends the lower portion of the drill stem 6 carrying the bit 8. The bit 8 is illustrated in the present instance as of a diameter small enough to pass through the collar 4. The assembly may, for eX- ample, be associated with the type of device illustrated in 'Kothny Patent 2,107,420 dated February 8, 1938, for ultimate removal of the whipstock otherwise than by engagement of its `collar by the bit.

At I il there is illustrated the conventional shear lpin connecting the collar of the whipstock and of preventing either relative rotary .or relative in any event, it must be withdrawn from the bore ,204

longitudinal movements of the drill stem and` whipstock.

In accordance with the present invention, a longitudinal slot I2 is formed in the whipstock collar 4, and extending into it and spaced from both its upper and lower ends is a second pin I4 threaded into the drill stem. This pin desirably fits the slot I2 in such fashion as to prevent on its own account, if the pin I0 becomes ineffective, any substantial relative rotary mo-vement between the drillV stem and the whipstock. The fit is preferably a loose one, so that normally there are no stresses on the pin I4.

In the normal operation of this device, if no accident occurs the pin I4 will have no function during the lowering operation. When the whipstock reaches its bottom position, the weight of the drill stem is permitted to shear the pin I0, the forces exerted during this shearing operation tending to force the lower end of the whipstock into the earth. The drill stem is then further lowered until the pin I4 engages the lower end of the slot I2, and again the weight of the drill stem is permitted to act to shear this second pin. The sole function of the pin I4, therefore, is to cause the whipstock to become imbedded more deeply in the formation due to the succession of this second shearing action.

The principal purpose of the pin I4, however, is to prevent loss of the whipstock or its orientation in the event an obstruction is encountered during the lowering. Under such circumstances, it is likely that before the lowering can be arrestedthe pin I0 `may be sheared oi. The

spacing of the pin I4 from the bottom of the slot I2 is desirably sulicient so that the drill stem may be arrested before that pinmay engage the lower portion of the slot and be sheared off also. If the second pin is not sheared off, the drill stem may be manipulated to try to get the whipstock by the obstruction and then lowered very gradually while the driller watches the Weight indicator. If the whipstock can now be lowered past the obstruction, neither the orientation nor the whipstock may be lost and the lowering may proceed to bring the whipstock to its iinal position. Thereupon, the weight of the drill stem is permitted to shear the pin I4, leaving the whipstock in desired position in the hole.

What I claim and desire to protect by Letters Patent is:

1. In combination, a drill stem adapted for rotation at the top of a bore hole, a whipstock, a shearable pin connecting the lower portion of the drill stem and the upper portion oi? the Whipstock, and additional means for holding the drill stem and Whipstock in assembled relationship and against substantial relative rotation after said pin is sheared, so that rotation of the top of the drill stem after shearing of said pin may eiect rotation of the whipstock, said means comprising a second pin on one engaged in a longitudinal slot in the other.

2. In combination, a drill stem adapted for rotation at the top of a bore hole, a shearable pin connecting the lower portion of the drill stem and the upper portion of the whipstock, and additional means for holdingthe drill stem and whipstock in assembled relationship and against substantial relative rotation after said pin is sheared, so that rotation of the top of the drill stem after `shearing of said-pin may effect rotation of the and the upper portion of the whipstock, and adwhipstock, said means comprising a second 'pin L on one engaged in an opening in the other, said opening affording a clearance space below said ysecond pin, and said second pin being under no substantial stress until the first pin is sheared.

ditional means for holding the drill stem and whipstock in assembled relationship after said pin is sheared so that rotation of the top of the drill stem after shearing of said pin may effect rotation of the whipstock, said means preventing substantial relative rotation between the drill stem and whipstock while allowing substantial .relative vertical movements between the drill stem and whipstock after said pin is sheared.

4. In combination, a drill stem adapted for rotation at theV top of a bore hole, a whipstock, means temporarily connecting the lower portion of the drill stem and the upper portion of the whipstock, yand additional means for connecting the drill stem and whipstock after the connection effected by the rst means is interrupted, 4s aid,.,f/rdditional means allowing substantial relative vertical movements between vthe drill stem and whipstock but preventing substantial relative rotation between the drill stem and whipstock, so that rotation of ,the top of the drill stem may effect rotation of the whipstock after the connec- -vtion effected by thefirst meansis interrupted.

ROBERT S. HYER.

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