US2766010A - Casing whipstocks - Google Patents

Description

Oct. 9, 1956 HESTER 2,766,010

CASING WHIPSTOCKS Filed March 6, 1953 3 Sheets-Sheet 1 Fred A. f/esfer INVENTOR.

BY X04 2. mad; KKM

Oct. 9, 1956 F. A. HESTER 2,766,010

CASING WHIPSTOCKS Filed March 6. 1953 5 Sheets-Sheet 3 A TTORNE Y6 Fred A. Hexsterv 2,766,010 CASING WHIPSTOCKS Fred A. Hester, Houston, Tex; Mildred Gibbs Hester, executrix of said Fred A. Hester, deceased Application March 6, 1953, Serial No. 340,783 7 Claims. (Cl. 25 5'-1.6

This invention relates to new and useful improvements in casing whipstocks.

Heretofore much difficulty has been encountered in positioning casing whipstocks in a casing at the window or milled-out longitudinal section thereof so that a directional drilling bit can be guided through the window into the formation adjacent thereto without damaging the whipstock. In the previously known casing whipstocks, there has been no means for assuring that the upper end of the whipstock is positioned to one side of the easing with the result that many times the directional drill bit cuts up the whipstock itself instead of being guided into the formation by the inclined guide surface of the whipstock.

Also, in the previously known casing whipstocks, the surface orientation of the whipstock is often lost because the whipstock has to be rotated to prevent premature hanging of the whipstock on the upper edge of the section of casing below the window.

It is therefore one object of this invention to provide an improved casing whipstock that is adapted to automatically align the whipstock in the casing with the upper end of the whipstock disposed to one side of the well bore whereby a directional drilling bit will be guided along the inclined guide surface of the whipstock without damaging the whipstock itself.

An important object of this invention is to provide an improved casing whipstock wherein a pair of slips are utilized for tilting the whipstock to one side of the well bore to thereby assure proper guiding of a directional drill bit.

Another object of this invention is to provide an improved casing whipstock which will be guided into the lower section of casing below the window or cut-away portion thereof without the necessity for rotating the whipstock during the lowering and setting of same in the easing, whereby the surface orientation of the whipstock is maintained and the direction in which the directional drill bit is guided by the whpstock is therefore known.

The construction designed to carry :out the invention will be hereinafter described, together with other features thereof.

The invention will be more readily understood from a reading of the following specifications and by reference to the accompanying drawing forming a part thereof, wherein an example of the invention is shown, and wherein:

Figure 1 is an elevational View of the casing whipstock of this invention, with the whipstock being anchored in a sectional casing below a window or a longitudinal cutaway section of the casing.

Figure 2 is a view, partly in elevation and partly in section, illustrating the upper portion of the casing whipstock of this invention.

Figure 3 is a side view of a portion of the upper whipstock section shown in Figure 2.

Figures 4, 4A, and 4B, are views, partly in elevation and partly in section, which together illustrate the lower or anchoring section of the casing whipstock of this invention, with Figure 4 illustrating the uppermost part of the lower or anchoring section, Figure 4A illustrating the intermediate portion, and Figure 4B illustrating the lowermost portion of the lower or anchoring section.

Figure 5 is a horizontal sectional view taken on line 55 of Figure 4.

Figure 6 is a, horizontal sectional vew taken on line 66 of Figure 4A.

As shown in the drawing, the guide section of the whipstock of this invention is designated by the numeral 10. The guide section 10 has a mandrel 11 extending down below and into an anchoring section 12, which has a pair of diametrically opposed gripping slips 14 and 15. As will be explained, the anchoring section 12 carries a latch mechanism 17 which is adapted to engage the upper edge of a section of easing or well pipe C, to restrain the downward movement of the anchoring section 12, whereby the slips 14 and 15 are set into gripping contact with the casing C upon a continued downward movement of the mandrel 11 with respect to the anchoring section 12. When the gripping slips 14 and 15 are set (Figure 1), the upper or guide section 10 is disposed adjacent a window or longitudinal cut-away portion W between the lower section of casing C and the upper section of easing C which extends to the surface of the well. When the whipstock of this invention has been set in the casing C (Figure 1), then the upper end of the guide section 10 is disposed to one side of the well bore in which the casing is located, so that subsequently a directional drilling bit (not shown) may be lowered into the casing C and thereafter guided by the guide section 10 into the wall of the well bore adjacent the window or longitudinal opening W.

The upper or guide section 10 is illustrated in detail in Figures 2 and 3. As can be seen therein, the guide section 10 has an inclined concave guide face or surface 20, which is adapted to receive a directional drill bit (not shown) at its upper end 20a, and guide such bit at an angle to the wall of the well bore adjacent the window W. The portion of the guide section 10 on the diametrically opposite surface of the section 10 from the guide face 20 includes a longitudinal rib 22 with lateral support ribs 23 at various points throughout its length. This longitudinal rib 22 forms the back or rear surface of the guide section 10 and is adapted to be positioned substantially parallel to the wall of the well bore adjacent the window W. Obviously, when the rear or back rib 22 of the guide section 10 is substantially parallel to the wall of the Well bore, the inclined concave guide surface 20 will be at an angle to such well bore Wall, and that angle may vary depending upon the direction the bit is to be guided, but preferably that angle is very small, on the order of three to five degrees to prevent excessive bending of the pipe which supports the drill bit as it is guided by the inclined face 20.

The guide section 10 has a lateral opening 25 therethrough for the reception of a shear bolt 26, which con nects a tubing type setting tool T to the whipstock for the lowering and setting of the whipstock in casing C. The tubing type setting tool T is diagrammatically illustrated in Figure 1 and may be of the conventional construction. The lower end of the guide section 10 has formed integral therewith, or afiixed by suitable means, a mandrel 11 which has a longitudinal recess 27 therein, a portion of which is shown in Figure 2, and the purpose of which will be explained hereinafter.

The details of the mandrel 11 are shown in connection with the anchoring section 12 in Figures 4, 4A and 48, wherein it can be seen that the anchoring section 12 includes an outer sleeve 30 surrounding such mandrel 11. The external diameter of the mandrel 11 is considerably less than the internal diameter of the sleeve 30, whereby an annular space 31 is formed between the sleeve 30 and the mandrel 11, the purpose of which will be explained later. When the whipstock is lowered into the casing,

prior to the time that the slips 14 and 15 are set in gripping contact with the casing C, shear pins or bolts 32 are provided to hold the mandrel 11 and sleeve 30 together, but after the shear bolts 32 are sheared, then the mandrel 11 may move downwardly with respect to the sleeve 30. It will be apppreciated, of course, that any number of shear bolts 32 can be utilized.

The lower end of the mandrel 11 is formed in the shape of a cone 34 so that upon lowering the whipstock into the lower section of easing C, the whipstock will automatically be guided into the upper end of such casing C without the necessity for rotating the whipstock. This conical section 34 prevents the loss of surface orientation of the whipstock, so that the direction of the inclined guide face 20 can be maintained at all times during the lowering of the whipstock and the setting of same in the casing C. An annular ring 35 is welded or otherwise secured to the mandrel 11 above the cone 34 to limit the movement of the mandrel upwardly with respect to the sleeve 30.

The upper gripping slip 14 is shown in Figure 4A, and therein it can be seen that the slip 14 includes a slidable jaw member having casing engaging teeth 38 on the exterior thereof, with the jaw member being radially movable through an opening 39 in the sleeve 30. The mandrel 11 has an expander surface 40 which is keyed to the inner portion of the jaw member or slip 14 by a tongue 41 which fits within a corresponding groove 42 on the inner portion of the slip 14 (Figure 6). Thus, as the inner mandrel 11 is moved downwardly with respect to the sleeve 30, the inclined expander surface 40 moves the gripping member 14 radially outwardly through the opening 39 into gripping contact with the interior of the casing C. Since the gripping jaw member 14 is disposed in the radial opening 39 in sleeve 39, the tongue and groove construction 41, 42 prevents the rotation of the mandrel 11 with respect to the sleeve 30, as well as preventing relative rotation between the gripping slip member 14 and the inner mandrel 11.

The gripping slip 14 is located in vertical alignment with the inclined guide face 29 of the upper guide section 10. The lower gripping slip 15 is constructed in an identical mann r with the upper gripping slip 14. The lower gripping slip 15 has gripping teeth 38 and a tongue and groove construction 41, 42' on the inclined surface 40', so that the gripping slip member 15 moves radially outwardly through the operating 39' in the sleeve 30. The lower slip 15 is located below the upper gripping slip 14 and is disposed on the opposite side of the sleeve 30 from the upper gripping member 14. the lower slip 15 is disposed 180 degrees from the upper slip 14, and is therefore substantially vertically aligned with the rear rib section 22 of the upper guide section 10. By reason of such positioning of the slips 14 and 15, upon a setting of same, after shearing of the shear pin or pins 32, there is a positive torque applied to the mandrel 11 which tilts the mandrel 11, and consequently the upper guide section in a direction tending to move the rear longitudinal rib 22 of the upper guide section 10 toward the wall of the well bore. Thus, considering the axis of the casing C to be along the center line L as shown in Figure 1, upon a setting of the slips 14 and the mandrel 11 will be moved laterally so that the longitudinal axis of the mandrel and the guide section will assume a line along L. Such tilting of the mandrel 11 relative to the sleeve 30 is possible by reason of the annular space 31 which provides a freedom of lateral movement between the mandrel 11 and the sleeve 39. Thus, as the inclined expander surfaces 40 to 49 are moved downwardly relative to the slips 14 and 15, respectively, the slips are moved radially outwardly until they engage the interior of the casing C. Upon such engagement, continued downward movement of the inclined surfaces cannot move the slips radially outwardly any further; consequently, the mandrel 11 must move laterally: As seen In other words,

in Figure l, the upper slip 14 then moves the mandrel 11 laterally to the left until the mandrel contacts the left side of the bore wall of the sleeve 30; substantially simultaneously, the lower slip 15 moves the mandrel 11 laterally to the right until it contacts the right side of the bore wall of the sleeve. It will be observed that the slips 14 and 15 thus actually serve as pivot points during the tilting of the mandrel 11 with respect to the sleeve 30, and the ultimate result is that the upper guide section 10 is tilted to the left of the vertical axis of the sleeve 30 and the casing C (Figure 1). In the usual case, the mandrel 11 will not be tilted to the full extent permitted by the annular space 31 because prior to the full tilting, the rear wall or rib 22 will contact the wall of the well bore. Of course, when such contact occurs, further tilting is unnecessary since the upper end 20a is properly positioned to one side of the well bore.

It should also be pointed out that because the slip 14 is vertically aligned with the whipstock guide face 20 and the slip 15 is vertically aligned with the rear side 22 of the guide section 10, with the slip 15 below the slip 14, the guide face 26 cannot be tilted toward the right of the vertical axis. Thus, even if the mandrel 11 where not undersize to permit tilting to the left, the slips 14 and 15 would prevent tilting of the guide section to the right. Furthermore, in some instances, after the mandrel 11 is tilted to the left its full extent, if the rear side 22 has not contacted the wall of the well bore, it is possible to further tilt the guide section 10 to the left by tilting the sleeve 30. This can be accomplished because the sleeve 39 generally has a considerably smaller outside diameter than the internal diameter of the casing C so that after the mandrel 11 has been tilted and a continued downward force is applied to the mandrel 11, the lateral movement of the mandrel by the co-action of the inclined surface 40 with the slip 14 will move the upper end of the sleeve 30 to the left (Figure 1) since the mandrel is contacting the left side of the sleeve at its upper end. Likewise, the lower end of the sleeve 30 is moved to the right by the slip 15 so that there is a pivoting of the sleeve 30 about the slips 14 and 15 and consequently a further tilting of the upper guide section 11 to the left, tending to move the rear side 22 into contact with the wall of the well bore.

The latching mechanism 17 which serves to initially stop the downward movement of the sleeve 39 for subsequently actuating the gripping slips 14 and 15 is shown in detail in Figure 4. This latching mechanism 17 includes a latch arm 45 which is pivoted to a bracket 46 by a pivot pin 47 extend-ing through the bracket 46. The bracket 46 is welded at 48 or otherwise suitably afiixed to the sleeve 30 so as to be integral therewith. The latch arm 45 has a projection 50 which has a lateral casing-engaging surface 51, which is adapted to engage with the upper edge of the casing C (Figure l).

The latch arm 45 is urged radially outwardly by a leaf spring 52 which is bolted to the latch arm by bolts 53. The inner end of the leaf spring 52 is curved at 52a and the curved surface 52a is adapted to slide on the inner wall 27:! of the recess or slot 27 in the mandrel 11 when the mandrel 11 moves relative to the sleeve 30.

Radial outward movement of the latch arm 45 is limited by the engagement of its upper end 45a with the inner surface of the sleeve 30 above the longitudinal open- 1 ing 30a in the wall of the sleeve 30. As the tool is lowered into the well casing prior to the positioning in the lower section of the casing C, the latch arm will normally be confined in the dotted line position shown in Figure 4 by reason of its engagement with the wall of the casing as it is lowered therethrough. However, even though the latch arm 45 may be urged radially outwardly through the opening 30a prior to the time that it is to engage the upper end of the lower section of casing C, the lateral curved section 55 on the projection 56 of latch arm 45 prevents the lateral surface 51 from engaging with the casing prior to the time that the lateral surface 51 contacts the upper edge of the lower section of casing C in which the whipstock is to be anchored.

In use, or operation, of the whipstock of this invention, the whipstock is lowered on a setting tool T with the shear pins 32 preventing the sleeve 30 and the mandrel 11 from prematurely separating and the shear bolt or pin 26 preventing the setting tool T in the whipstock from prematurely separating. After the whipstock has been lowered into the casing and the cone or whipstock alignment member 34 has directed the whipstock into the lower section of casing C, the latch member 17 engages with the upper edge of casing C, with the lateral surface 51 effecting the engagement. Once the latch mechanism 17 has restrained the further downward movement of the sleeve 30, then the continued lowering of the mandrel 11 by lowering of the tubing setting tool will shear the pin or pins 32. It will be observed that the shear pin 32 must be of a lesser strength than the shear pin 26 so that the shear pin 32 will initially shear prior to the release of the tubing setting tool T. The downward movement of the mandrel 11 relative to the sleeve 30 effects a radial expansion of the gripping members 1 and 15 simultaneously, because the inclined expanding surfaces 40 and 40 are of the same but opposite angle. As the slips 14 and 15 are set in gripping contact with the lower section of casing C, the mandrel 11 and the upper guide section 10, and in some instances the sleeve 30, are pivoted or tilted so that the upper end 20a of the whipstock guide surface 20 is disposed to one side of the well bore. As pointed out previously, the lateral movement of the mandrel 11 is made possible by reason of the annular space 31 which provides a freedom of lateral movement of the mandrel 11 relative to the sleeve 30 during the setting of the slips 14 and 15. Also, the annular space between the sleeve 30 and the casing C permits the lateral pivoting of the sleeve 30 relative to the casing C. Of course, once the rear side 22 of the guide section contacts the wall of the well bore, the guide face 20 is properly positioned and further tilting is not possible. It will be noted that as the mandrel 11 is lowered relative to the sleeve 30 for setting the slips 14 and 15, the curved section 52a of the spring 52 will ride on the inner wall 27a of the recess 27 in the mandrel 11, so that it is immaterial how far down the mandrel 11 moves insofar as the spring action of spring 52 is concerned.

After the slips 14 and 15 are set and the whipstock is otherwise ready for use, a weight is applied to the tubing type setting tool T to shear the pin 26, whereby the setting tool T may be removed and the directional drilling bit may be lowered for guiding along the inclined concave guide surface of the guide section 10 into the wall of the well bore through the window W. The direction in which the directional drill bit will be guided is indicated in Figure 1 by the dash-dot lines.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof, and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made, within the scope of the appended claims, without departing from the spirit of the invention.

What is claimed is:

1. A casing whipstock adapted to be anchored in the lower section of a well casing formed by cutting out a portion of the casing thereabove to provide an upper section of casing spaced from the lower section, said upper section extending to the surface of the well, said whipstock being adapted to guide a directional drill bit through the space above said lower section into the wall of the well bore at an angle to the axis of the casing, said whipstock comprising an upper guide section releasably suspended from a lowering tool including an inclined guide surface for guiding the directional drill bit, a mandrel secured to the lower end of said guide section and extending downwardly therefrom, a tubular sleeve loosely surrounding said mandrel and releasably secured thereto, said mandrel and tubular sleeve when secured together being adapted to be lowered into the lower section of the well casing by said lowering tool, said tubular sleeve having a longitudinal slot therein, latch means mounted on said sleeve, resilient means normally projecting said latch means into said slot, a recess in said mandrel longitudinally aligned with said slot to receive said latch means when said means is in retracted position, said latch means in the extended position thereof being adapted to engage the upper marginal edge of said lower casing section, a pair of gripping slips slidably mounted on inclined guideways on said mandrel, openings in said tubular sleeve through which said slips project, the walls of said openings embracing said slips to prevent longitudinal movement thereof, but permitting lateral movement thereof, whereby downward movement of said mandrel will cause said slips to be projected through said openings to engage the inner wall of said lower section, said pair of slips being vertically spaced and diametrically positioned on said mandrel, the upper slip being in longitudinal alignment with said guide section, said mandrel beng enabled to move further downwardly with respect to said tubular sleeve when released therefrom but still suspended from said lowering tool.

2. The structure set forth in claim 1, wherein said inclined guideways on said mandrel move said slips radially outwardly simultaneously, said guideways being adapted to effect outward radial movement of said slips upon release of said mandrel and said sleeve to permit relative downward movement of said mandrel with respect to said sleeve.

3. The structure set forth in claim 1 including shear pins for releasably securing the tubular sleeve which surrounds said mandrel to said mandrel to prevent relative axial movement of said sleeve and said mandrel, to maintain said mandrel in elevated position relative to said tubular sleeve whereby the slips will be held in ret-racted position.

4. The structure set forth in claim 1, including means on the lower end of said whipstock for guiding said whipstock into said lower section of casing without rotation of the whipstock, whereby the surface orientation of the inclined guide surface is maintained.

5. The structure set forth in claim 1, wherein there is an annular space between the exterior of the mandrel and the interior of the sleeve to permit tilting of the mandrel and the upper guide section when the slips are set to assure that the upper end of the upper guide section is positioned at one side of the well bore, whereby upon lowering the directional drill bit, the bit will not engage said upper end but will be guided by said inclined guide to thereby avoid damage to said whipstock by the drill bit.

6. The structure set forth in claim 1, wherein the lower end of the mandrel has a conical pilot for guiding the whipstock into the open upper end of said lower section of casing without the necessity for rotating the whipstock, whereby the surface orientation of the whipstock is maintained.

7. The structure set forth in claim 1, wherein said latching means includes a latch arm pivoted to said sleeve with a resilient means on said latch arm and in contact with the wall of said recess to urge said latch arm outwardly through said longitudinal opening in said sleeve.

References Cited in the file of this patent UNITED STATES PATENTS 2,132,061 Walker Oct. 4, 1938 2,145,422 Kinzbach Jan. 31, 1939 2,312,656 Le Bus Mar. 2, 1943 2,633,331 Hampton Mar. 31, 1953

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