US 2544982 A
Description (OCR text may contain errors)
March 13, 1951 R. BUTTOLPH WHIPSTOCK Filed Nov. 14, 1946 Ralph Buol h INVENTo bore.
Patented Mar. 13, 1951 UNITED STATES PATENT OFFICE'.
' Y 2,544,982V Y t WHIPSTO'CK Ralph Buttolph, Long Beach, Calif., assignor /to Eastman Oil Well Survey Company, Denver, Colo., a corporation of Delaware Application November 14, 1946,v Serial No.'709,711
This invention relates to new and useful iin-,- provements in whipstocks. This application is led .as a continuation-in-part of application Serial No. 535,235, now abandoned, in which I am a co-inventor.
One object of the invention is to provide an improved whipstock of --the removable type, such as is illustrated in the patent to McVicar No. 1,970,761, the invention being an improvement on the device disclosed in such patent.
`In the usual removable whipstock, as exempli- Z'ed by McVicar, wherein the drill bit is utilized '-to withdraw the whipstock from the wellv bore, 'the drill blt c'o-acts with a collar at the upper end of the whipstock body whereby'vsaid whipstock may be raised and lowered by means of said bit. The whipstock body is generally arcuate in Icross section with a' longitudinal inclined guide surface. The outer surface of the body is `disposed on a radius which iswswung from the longiA tudinal center of the body whereby said outer surface is substantially concentric with the well bore into which it is lowered. Because .this outer surface of the whipstock body is of the-.same radius throughout its length and also because said body is of considerable length it is impossible to lower a full gauge whipstock, that is a whipstock of the same size as the well bo-re, into said As is well known a well bore has irregularities thereinl and a whipstock having considerable length of th'e" same size as said bore will not pass such irregularities and therefore, cannot be lowered therethrough. For this reason .itis'neces'sary to employ a whipstock which is smaller` than the well bore in order to assure lowering of thesazne into proper position. The
aisle of a whipstock smaller than the well bore causes the use of an undersize o-r smaller bit which means that the oiset bore drilled by the bity is less than the diameter ofthe main well bore.
In such instance, a reaming operation lmust be performed after the oifset bore has been started y 'ing the advantage of being capable of drilling a substantially full-gauge offset bore, whereby the.
usual reamingl operation in said offset bore is eliminated. 1 V'An important object of thisinvention is to provide an improved removableA whipstockwhich j is solconstructed that a large bit only slightlyV less 5- claims. (c1. c55-1.6)
than the-main well bore diameter, may be combined therewith, whereby the offset bore which is drilled by said bit is substantially full-gauge, that is,r said offset bore Ais of substantially the same .diameter as the main well bore in which the whipface maintained at a fixed distance from the lon- .gitudinalcenter ofthe whipstock; this construction making it possible to lower the whipstock into a well bore having adiameter of substantially the same size aslsaid whipstock, whereby a substantially full-gauge bit may be employed in .drilling oi of said whipstock.
lA particular object ofthe invention is to rprovide an improved whipstock having its body portic-n substantially arcuate or semi-circular in Avcross-section and having the center of the radius of the outer curved surface of said whipstock graduallychanged in a longitudinal plane from the upper to the lower end of said whipstock,
.whereby the outer curved surface cf said whipstock is progressively spaced a greater distance from thetrue longitudinal center'of the tool to'- ward its lower end; this construction permitting the whipstockto pass downwardly through 'a bore of substantially the same diameteras the drill bit carried by said whipstock and at the same time permitting the whipstock tc function iefficiently during the .fdrilling olf operation.
A further object of the invention is to provide an limproved whipstock, of the character described, having the opening for accommodating the drill bit of such contour that any type of drill biteither adrag-or rock bit, may be combined with the whipstock.
The construction designed to carry out thevin.- vention willAf be hereinafter described together with other features of the invention. The invention will be more readily understood from a reading of the following specification and "by reference to the accompanying drawing,
wherein an example of the invention is shown.
Figure l is an elevation of a whipstock con- :structed in accordance with the invention and illustrating :the drill bit in an. attached position, y Figure. 2 is j a transverse, vertical,l sectional view showing the whipstock in its set position and the drill bit detached from said whipstock. y Figure 3 is an enlarged, horizontal, cross-sectional view taken on the line 3-3 of Figure l,
Figure 4 is an enlarged, horizontal, cross-sectional View taken on the line 4 4 of Figure l,
Figure 5 is an enlarged, horizontal, cross-sectional view taken on the line 5-5 of Figure 1 Figure 6 is an enlarged, horizontal, cross-sectional view taken on the line 6 6 of Figure l, and
Figure '7 is an enlarged, horizontal, cross-sectional view taken on the line 1--1 of Figure 1.
In the drawings, the letter A designates a whipstock including an elongate body portion I0 which is generally arcuate in cross-section and which will be hereinafter described in detail. A collar II is preferably formed integral with the upper end of the whipstock body and the bore or openi tegral with its upper end.
whipstock body A is so constructed that the drill bit used with the whipstock drills a substantially full gauge hole. By means of the present invention a whipstock of substantially the same size as the Well bore, so far as the operating function of said whipstock is concerned, may be lowered into the well bore and will readily pass through said bore to the desired position at which it is to be set. Thus, the disadvantage of having to employ an under size whipstock and consequently an under size drill bit in a particular size-bore is eliminated.
The whipstock body A is elongate and as has been stated hasthe recovery collar II made in- Immediately below the collar, the whipstock has a straight wall secjtion l1, arcuate in cross-section, with the ining I2 through uns @011er is offset from. the een Y ter of said collar, as is clearly shown in Figure 3. A drill blt' I3 Which is attached'to a. Sub I4 y is disposed below the collar and has a portion thereof iitting within the arcuate upper portion of the whipstock body. The drill bit is larger than the opening through the collar so that it cannot pass therethrough with the result. that the whipstock A may be suspended from the bit. The subl I4 is coupled to the lower end of a drill pipe I5 and has an outer diameter which permits the sub to extend through the opening I2 of the collar II. A shear pin I6 Aconnects the 4sub to the collar and with thisarrangement the whipstock may be lowered into the well bore B by means of the drill pipe. Shearing of the pin I6 after the whipstock A is set permits the drill bit and pipe to be moved downwardly relative to said whipstock, whereby the drill bit Will be guided outwardly by the whipstock body to'drill an offset or inclined bore.
gether with the offsetting of the bore I2 in' the collar I i. Ordinarily in the usual whipstock, such as shown in the patent to McVicar No. 1,970,761,
it has been the practice to construct the whipstock body with the outer surface of the whipstock body curved on a radius having its center aligned with the longitudinal center-of said body. 'With such arrangement the whipstock has its outer surface substantially concentric to the wall of the well bore into which it is lowered. Because of this concentricity between the outer-surfaceof the body of the whipstock` and thefwell'bore, it is necessary that the whipstock be under-gauge or smaller than the well bore before it is possibe to lower the whipstock therethrough. This is caused by the fact that the whipstock body has -a considerable length and the well bore isirregular which factors combine to make it impossible to lower a full-gauge Whipstock therethrough; there must be some clearance between v the outer surface of the whipstock body and the inner wall of the well bore and this clearance has l.,
been obtained by employing the under'size'whip- "j stock. Manifestly, the use of 'a reduced size whip- "stock requires that a small bit be usedso-that :subsequent reaming operations are necessary- YSince the drill bit I3 is. 'larger than the opening I2 in the collar it is apner wall I8 of this section being substantially parallel in a vertical plane to the outer surface of the Whipstock. When the drill bit is connected to the whipstockffFigure l), a portion of said bit. engages the straight wall section. It is noted that the section I1 may be made relatively thin sothat this section together Ywiththe bit diameter is equal to the diameter of the well bore. Therefore, the bit` I-3 isv substantially full gauge being less than the diameter of the well bore B only by theA thickness of the wall section II` Below the section Il, the whipstock body is formed with an inclined guide' face I9 which is concave and which merges into the lower end of the straight sectionV I'I. In order to obtain ,eifective drilling and desired angle, the radius R of the concave guide face I9 which is engaged by the drill bit must remain constant from its upper end to its lower end; thel inclined guide surface is, of course, disposed at the desired angle -which varies a predetermined number of degrees per foot of length, The radius R of the concave guide face i9 is in accordance with the particular diameter bit which is. employed since the purpose of this face isA to provide a partial seat for the bit as it moves downwardly of the whipstook. Since the face I9 is on a gradual inclination extending from its upper and lower end and since the radius R remains constant, the shiftingv of the center point of the radius R along the line L, as illustrated in Figures, 4 to '1, is in accordance with the degree of inclination of the face I9.'- In other Words, an imaginary line drawn through all of the center points of the radii R .extends` parallel to the inclination of the face I9vas shown in Figure 2.
By providing the inclined guide face, which increases the thickness of the whipstock body at its central portion from itsf upper to its lower end, the bit is moved radially outwardlyvof the main well bore as said bit is lowered longitudinally 0f the whipstock andthus, the bit is forced outwardly into the' formation at one side of the main well bore to drill an inclined bore at a desired angle with respect' to said main bore B. Thev construction and' function of the concave guide face I9 is usual in all whipstocks.
To hold the guide face against displacement when the drilling operation commences, the outer .wall or trailing side 20 of the whipstock must engage the well bore Wall. As has been stated, according to prior practice this outer wall 20 of the'whipstockrhas been made concentric to the wall of the well bore, said outer wall being formed on a constant lradius throughout the entire length of the whipstock body. The construction .of the bodywith its outer surface onra constant -Incarrying out-the 'presen-tiinventiorhitheesradiuswillprevent Athe-whipstockfromA entering a bore' having that same radius because as ex-` outer surface constructed along Va radius which gradually and progressively diminishes or is reduced toward its lower end. However, although naar the radius of the outer surface of the body progressively changes the outer longitudinal central portion of said surface, indicated by the letter Din Figures 4 to 7, is spaced a constant distance from the longitudinal center, indicated at C, of the whipstock body throughout the length of the body. Referring to Figure 4, the outer surface of the upper end of the whipstock body is formed o n-the radius RI being swung on the longitudinal center C of the body. At the horizontal line 5 of Figure l, the radius of thev outer surface of the body has been reduced to the radius R2 shown in Figure 5 with the reduction in radius being effected by spacing the center C2 of the radius R2 from the longitudinal center C of the whipstock body. The spacing of the center C2 from the center C is in a longitudinal plane L which extends through the center C and the central portion D of the outer surface of the body and thus `the distance between the central portion D and the longitudinal center C remains constant even though the radius of the outer surface has been diminished. The change in radius of the outersurface of the whipstocl: body from the radius Rl to R2 is gradual or progressive so that it is' understood that the radii of the outer sur-I face of the whipstock between the horizontal lines 4 4 and 5 5 of Figure l are progressively less with the center points of such radii being disposed between the longitudinal center C of theV center lpoint C2 ofFigure 5. 4The area of the outer surface ofv the whipstock between the lines 5 5 and 6 5 of Figure l is formed on radii which are gradually reduced from the radius'R2 to the radius R3 and have their center points in the longitudinal plane L between the centerpoint C2 and C3.r
In Figure 7, the further reduction in radius is illustrated Aat the line f l' of Figure i. The radius R4 at this point is less than the radius R3 and is swung on a. center C4 which is located in the longitudinal plane L but spaced from the center C3. The area of the cutersurface of the whipstock between the lines -S and' 'E 'i is on diminishing radii having their centers disposed between thecenter points C3 and C4. Below the horizontal plane 1 1, the radius of the outer surface of the whipstock continues to reduce in the same manner as above with the center points oi' theY progressively diminishing radii always remaining `in the longitudinal plane L and each 'oeing spaced slightly closer to the central portion D of the outer surface, whereby the distance between the portion D and the center C of the whipstock body remains constant throughout the length of the whipstock.
As'the outer surface of the whipstock body is eKTA gradually and progressively reduced and since distance between the central portion of the outer'f surfaceand the center C is maintained constant;
clearance or by-pass areas E are formed between the sides or remainder of the outer surface of the whipstock body and the well bore.
It is noted that the radius RI,
wall of the well bore at the horizontal plane 4 4 of Figure 1; from the plane, the radius of the outer surface progressively decreases to the lower end of the body as above explained and the amount of decrease in' radius maybe varied tof obtain the desired size by-pass area E'. Thefl smallest radius is, of course, -at the extreme lower end of the body and its center is determined be-'' cause it is swung from the central portionD of the whipstock body. Thus, after the size ofthe from the center point of the smallest radius at the lower end of the body. It is desirable that the change in external diameter be gradual and thus.
the infinite number of gradually reducing radii,A
some of which. are indicated by the radii R2, R3
and Ril,v are disposed on an infinite number of center points on the line L between the centerv point'of the largest radius R at the upper end of the whipstock body and the center point of the' smallest radius (not shown) at the extreme lower end of said body. By observing Figures 4 to 7 it will be evident that the longitudinal center D of the outer surface of the whipstock body remains in contact with the well bore throughout its entire length so as to form a support which willprevent displacement of the whipstock during the,
bore since. there is sufficient clearance" between Y the major portion of. the .,outerf. surface of the whipstock body and the well bore to allow the" elongate body to pass downwardly throughthe irregularities of a well b'ore. rHowever, because the longitudinal center D of the curved outer surface of the whipstock body engagesgthe well bore, the function or eiect, so far as drilling off is concerned, of a' full 'gauge whipstock is ob.-
tained. p The outer surface of the `whipstock may be formed with a plurality oi ribs 2i which will func-v tionk to resist rotation of the whipstock duringf the drilling off operation. However, if desired,.-
these ribs may be omitted since they are essential to the invention.
From the foregoing it will be seen that an ini-y proved type of whipstock is provided.y The par-` ticular construction permits the use of asubstantially full gauge drill bit, whereby the offset bore which is drilled is suiiiciently close to the original bore yB that no reaming operationis necessary;A The whipstock functions as a full gauge whipstock but'because of the progressively diminish-` ing radius ofthe outer surface of the whipstoclrA body toward its lower end, a suioient clearance between said body and the well bore is providedl to allow a free lowering of the whipstock through the bore. The construction is such that the longi-V not:
as shown inv Figure 4, is substantially concentric to the inner tudinal central portion of the. outer surface.y oi.
`the whipstock. indicated. at D is constantv engagement with the well bore, whereby when the drill is guided' outwardly by the inclined guide face l'9 the whipstock will not be displaced out of position. The particular construction. also allows the inclined guide face i to have a constant radius throughout its length with the inclination of. the face being a. predetermined number of degrees per foot in accordance with. the required: angle.
` The openingY I.2 in the collar il. is offsetVV outof alignment with the center of the collar., said olfset being in a direction away from the straight wall section ll of the whipst'ock body. This allows a maximum size bit to be employed since it increases the shoulder i3a formed between the openingV l2' andtheinner Wall lll of; the section ll. g In use, the whipstock is lowered in the usual Inanner bynreans of the drill. bit and isset in the desired. position. The weight. of theY drill pipe is then imposed upon the shear pin Ib to' fracture the same and. permit downward. movement of the bit along the guide face of the whipstock. It is noted that the straight wall section il of the Whipstock body facilitates the shearing or fracturing of the pin since it allows the bit to move' straight downwardly for a distance before engagng. the inclined surface. This4 obviates any possibility of the. bit becoming wedged against the well bore during the shearing operation. After drilling is complete the bit and drill pipe are lifted and obviously the whipstock will beV withdrawn therewith.
. The device is exceptionally simple in construction and provides a distinct' advantage over whipstockswhich have been in general use and which, ashas been pointed out, have the outerv surface of their body portion on a constant radius throughout its length so that such outer portion is concentric to the inner wall of the well bore; The advantages of the present invention are accomplished through the particular arrangement of the progressively diminishing radius toward itslower end of the outer. surface o the body portion A oi said whipstock.
, The foregoing description of. the invention is explanatory thereof and various changes in the size, shape and materials, as well as inthe details of the illustrated construction may be made, within thev scope of the appended clairns, without departing from the` spirit of the invention.
What I claim and desire to secure by Letters Patentis:
l. A whipstock including, an elongate wedgeshaped body which is generally' arcuate in crosssecton, a collar secured to the upper end of the body, a drill pipe slidable through the collar, a drill. bit mounted on the lower end. of the drill pipe below the collar and having a diameter at least .equal to the distance between the inner wall. of the upper end of the whipstock' body and the wall of the well bore, the wedge-shaped body having an inclined guide face for guiding. the
bit outwardly into the formation and the outerY located in a longitudinal plane which intersects the longitudinal center of the body and the center of the curvature on the outer surface of said.
body, th e center or the curvature being so disposed with respect to the longitudinal center line or axis of the body and its collar that the longie tudinal central portion of thecurved outer surface is spaced the same distance from the center line or axis of the body and collar throughout the entire length of the body.
2; A whpstock including, an elongate wedgeshaped body which is generally arcuate in crosssection,` a collar secured to the upper end of the body, a drill pipe slidable through the collar,l a drill bit mounted on the lower end of. the drill'A pipe below the collar and having a diameter at; leastequal to the distance between the inner wall of the upper end of the whipstock, body andthe wall of` the well bore, said whipstock body having an elongate inclined guide face which is disposed. at an angle with respect tothe longitudinal center line or. axis of the body and the collar at the upper end thereof, and the outer curved surface of said body being formed on radii at planes. spaced vertically from each other along the longitudinal axis of the body from top to bottomtheref of, said radii progressively decreasing toward the. lower end of the body, the center points of the progressively decreasing radii being located in a. longitudinal plane which intersects the longitudl nal center of the body and the center of the curvature on the outer surface of said body, the.
center of the curvature being so disposed with respect to the longitudinal center liney or axis of the body and its collar that the longitudinal' c entral portion of the curved outer surface. is spaced the. same distance from. the center line. or. axis of the body and collar throughout the entire length'. of the body.
3. A whipstock including, an elongate body which isgenerally arcuate in cross-section, a collar secured to the upper end of the body,` a straight wall section arcuate in the cross-section immediately below the collar at the upper endoiv the body, that portion of the body below said straight section being Wedge-shaped with an inclined guide surface extending longitudinally along one side thereof, the outer surface. of the wedge-shaped portionbeing curved with said curvature being formed on radii at planes spaced vertically from each other along the longitudinal axis of the body from` top to bottom thereof, said'l radii progressively decreasing toward the lower end of the body, the center points of the progressively decreasing radii being located in a longitudinal plane which intersects the longitudinal center of the. body and the center of the curva-- ture on the outer surface of said body, the center of the curvature being so disposed. withrespect to the longitudinal center line or axis of the body and its collar that the longitudinal central portion of the curved outer surfaceis spaced the same distance. from the center line or axis. of the body and collar throughout the entire length of the body.
4.y A whipstock as set forth in claim 3,. where.- in an opening extendsA through the collar and is offset with respect to the center of said. collar.
5. A whipstock including, an elongate body which is generally arcuate in cross-section, a col-9.` lar secured to the upper end of the body, a straight wall section arcuate inthe cross-section immediately below the collar at the upper endof the body, that portion of the body below .said straight section being wedge-shaped with an inclined guide surface extending longitudinally along one side thereof, the outer surface of the wedge-shaped portion being curved with. said curvature being formed .on radii which progres? 9 sively decrease toward the lower end of the body, the center points of the progressively decreasing radii being located on transverse planes spaced vertically from each other along the longitudinal axis of the body from top to bottom thereof and also being located along a longitudinal plane which intersects the longitudinal axis of the body and the center of the curvature on the outer surface of the body, with said center points of the decreasing radii being disposed in spaced relationship to each other outwardly from the center of the body and with the center point for the smallest radius being farthest from the axis of thebody, the distance between the center of the curvature on the outer surface of the body and 15 2,334,747
the longitudinal axis of the body remaining constant throughout the length of the body.L
f RALPH BUTTOLPH.
REFERENCES CITED The following references are of record in the le of this patent:
UNITED STATES PATENTS 10 Number Name Date 973,537 Miller Oct. 25, 1910 1,625,600 Getty Apr. 19, 1927 1,970,761 McVicar Aug. 2l, 1934 2,065,896 Keever Dec. 29, 1936 Brantly Nov. 23, 1943