U.S. patent application number 09/732289 was filed with the patent office on 2002-06-13 for whipstock orientation system and method.
Invention is credited to Buyaert, Jean P..
Application Number | 20020070018 09/732289 |
Document ID | / |
Family ID | 24942955 |
Filed Date | 2002-06-13 |
United States Patent
Application |
20020070018 |
Kind Code |
A1 |
Buyaert, Jean P. |
June 13, 2002 |
Whipstock orientation system and method
Abstract
A whipstock assembly and method of operation is disclosed that
automatically orients itself within a wellbore to a known first
rotational position. The whipstock assembly is mounted on bearings
that permit free rotation of the whipstock assembly within the
wellbore. Due to gravitational forces, the eccentric weight load of
the whipstock will automatically orient itself on the low side of
the wellbore. Most wellbores are angled and the angle, azimuth,
depth and other information about the wellbore is known so that the
operator will know what position the whipstock assembly will
automatically assume. A lower orientation section of the whipstock
assembly is clamped into that first rotational position such as by
a lower packer and/or slips. The whipstock is then rotated to the
desired orientation by reciprocating the wellbore string. The
whipstock is then clamped into the desired rotational position by
activating an upper packer and/or slips. The running tool is
removed and drilling or milling can be initiated. After the new
wellbore is completed, the whipstock assembly can be retrieved from
the wellbore or relocated to a different borehole depth to be used
to drill or mill another new borehole section.
Inventors: |
Buyaert, Jean P.; (Houston,
TX) |
Correspondence
Address: |
William E. Johnson, Jr.
THE MATTHEWS FIRM
Ste. 1800
1900 West Loop South
Houston
TX
77027
US
|
Family ID: |
24942955 |
Appl. No.: |
09/732289 |
Filed: |
December 7, 2000 |
Current U.S.
Class: |
166/255.3 ;
166/117.6; 166/50; 175/61; 175/80 |
Current CPC
Class: |
E21B 23/01 20130101;
E21B 7/061 20130101; E21B 23/006 20130101 |
Class at
Publication: |
166/255.3 ;
166/50; 166/117.6; 175/61; 175/80 |
International
Class: |
E21B 007/06; E21B
007/08 |
Claims
What is claimed is:
1. A method for orientating a whipstock in a selectable direction,
said method comprising: utilizing a wellbore string for positioning
a whipstock assembly containing said whipstock at a depth within a
borehole section that is angled in a known direction; providing
that said whipstock assembly is initially free to rotate within
said borehole such that a weighted portion of said whipstock
assembly is automatically oriented by gravitational forces in a
first rotational position.
2. The method of claim 1, further comprising: affixing an
orientation section of said whipstock assembly with respect to said
borehole; and rotating said whipstock with respect to said
orientation section to a second rotational position.
3. The method of claim 2, further comprising: affixing said
whipstock with respect to said borehole in said second rotational
position.
4. The method of claim 3, wherein said step of affixing said
whipstock comprises setting a packer.
5. The method of claim 1, further comprising engaging a radially
moveable member with respect to said borehole to thereby affix an
orientation section of said whipstock assembly in said first
rotational position.
6. The method of claim 1, further comprising: providing that said
whipstock assembly is rotatable independently from said wellbore
string.
7. The method of claim 1, further comprising: releasing said
whipstock assembly from said wellbore string, initiating drilling
of a first new borehole section using said whipstock assembly,
reattaching said wellbore string to whipstock assembly, and
repositioning said whipstock assembly at a second desired depth for
drilling a second new borehole section.
8. The method of claim 1, further comprising: affixing an
orientation section of said whipstock assembly by setting a
packer.
9. A method for orientating a whipstock in a selectable direction,
said method comprising: positioning a whipstock assembly containing
said whipstock at a depth within a borehole; affixing an
orientation section of said whipstock assembly with respect to said
borehole in a first rotational position; and rotating said
whipstock with respect to said orientation section to a second
rotational position.
10. The method of claim 9, further comprising: affixing said
whipstock with respect to said borehole in said second rotational
position responsive to receiving a signal with at least one
transducer in said whipstock assembly.
11. The method of claim 9, wherein said step of rotating further
comprises: reciprocally moving a wellbore tubular string a selected
number of reciprocal strokes.
12. The method of claim 11, wherein each said reciprocal stroke is
translated into a specific amount of rotation of said
whipstock.
13. The method of claim 11, wherein each of said steps of affixing
comprise setting a packer.
14. A method for orientating a whipstock in a selectable direction,
said method comprising: positioning a whipstock assembly containing
said whipstock at a depth within a borehole section with a wellbore
string; and reciprocally moving a wellbore string a selected number
of reciprocal strokes such that each said reciprocal stroke is
translated into a known amount of rotation of said whipstock.
15. The method of claim 14, further comprising: providing that said
whipstock assembly is initially freely rotatable within said
borehole section such that gravitational forces move said whipstock
assembly to a first rotational position.
16. The method of claim 15, further comprising: affixing an
orientation section of said whipstock assembly in said first
rotational position.
17. The method of claim 16, further comprising: detecting a signal
with said whipstock assembly to initiate said step of affixing.
18. The method of claim 16, further comprising: utilizing
compressed gas for said step of affixing.
19. The system of claim 17, further comprising: affixing said
whipstock with respect to said borehole at a second rotational
position.
20. A whipstock assembly for use in a wellbore, comprising: a
whipstock with a guide surface; an orientation section; a
rotational connection between said whipstock and said orientation
section; and one or more radially moveable members secured to said
orientation section, said one or more radially moveable members
being radially moveable from a nonengaged position with respect to
said wellbore to an engaged position with respect to said wellbore
for affixing said orientation section in a first rotational
position.
21. The assembly of claim 20, further comprising: one or more
second radially moveable members secured to said whipstock, said
said one or more second radially moveable members being radially
moveable from a nonengaged position with respect to said wellbore
to an engaged position with respect to said wellbore for affixing
said whipstock in a second selectable rotational position.
22. The assembly of claim 20, further comprising: a mechanical
motion translator for translating reciprocal movement of said
wellbore string into rotational movement of said whipstock with
respect to said orientation section.
23. The assembly of claim 20, further comprising: a transducer
attached to said whipstock assembly for receiving a signal.
24. The assembly of claim 20, further comprising a container for
compressed gas.
25. A whipstock assembly for use in a wellbore, said whipstock
assembly being moveable to a selectable depth with a wellbore
string, said whipstock assembly comprising: a whipstock with a
guide surface; one or more bearings mounted with respect to said
whipstock assembly such that said whipstock assembly is rotatable
with respect to said wellbore, a heavy side of said whipstock
assembly, said heavy side being automatically positioned by gravity
in a first rotational position.
26. The whipstock assembly of claim 25, further comprising: one or
more radially moveable members secured to said whipstock assembly,
said one or more radially moveable members being radially moveable
from a nonengaged position with respect to said wellbore to an
engaged position with respect to said wellbore.
27. The whipstock assembly of claim 26, further comprising: one or
more transducers for receiving a signal, said one or more radially
moveable members being radially moveable in response to said
signal.
28. The whipstock assembly of claim 25, further comprising: an
orientation section, and a selectably rotational connection between
said whipstock and said orientation section.
29. The whipstock assembly of claim 25, further comprising: a
compressed gas chamber.
30. A whipstock assembly for use in a wellbore, said whipstock
assembly being moveable to a selectable depth with a wellbore
string, said whipstock assembly comprising: a whipstock with a
guide surface; a first set of one or more radially moveable members
secured to said whipstock assembly, said one or more radially
moveable members being radially moveable from a nonengaged position
with respect to said wellbore to an engaged position with respect
to said wellbore; and a second set of one or more second radially
moveable members secured to said whipstock assembly, said one or
more second radially moveable members being radially moveable from
a nonengaged position with respect to said wellbore to an engaged
position with respect to said wellbore, said first set of one or
more radially member and said second set of one or more second
radially moveable members being independently operable for moving
from said nonengaged position to said engaged position.
31. The assembly of claim 30, further comprising: one or more
transducers for receiving one or more signals, said first set of
one or more radially moveable members and said second set of one or
more second radially moveable members each being operable
responsively to receiving said one or more signals.
32. The assembly of claim 30, further comprising: one or more
compressed gas chambers.
Description
BACKGROUND OF THE INVENTION
[0001] (1) Field of the Invention
[0002] The present invention relates generally to whipstock
orientation and, more particularly, to a whipstock assembly that
when positioned downhole automatically orients to a known reference
position from which selectable whipstock orientation adjustments
can be effected.
[0003] (2) Description of the Prior Art
[0004] It is often desirable, in both cased and open hole, to
branch off one or more times from an existing wellbore or to
sidetrack away from an object such as a fish or toward an object
such as a revised geological target. A whipstock may be used as a
guide for the drill bit or mill in creating the new borehole
sections, casing windows, and the like, so that the new borehole
section is oriented in the desired direction. The whipstock is
anchored in the wellbore at the desired depth at which the new well
is to be kicked off. The bit or mill engages the generally metallic
whipstock face or surface that is typically angled so as to urge
the bit or mill in a desired direction. In this manner, it is well
known that the mill or drill bit is thereby directed to mill or
drill in the direction intended for the new wellbore section.
[0005] However, orienting the whipstock to direct the drill bit or
mill, as may typically be desirable for drilling the new wellbore
through a particular formation of interest, has been a problem. For
the new wellbore to be drilled in the desired direction, the
whipstock face must be oriented in the wellbore such that the
whipstock face is positioned to guide the bit or mill in that
direction. While the whipstock may be lowered on a wellbore string
such as a tubular string, the wellbore string will often be quite
flexible due to the length thereof so that the direction in which
the whipstock is pointing cannot be determined based on the
orientation of the wellbore string at the surface. Various methods
have been used in the past for orienting the whipstock but these
methods generally require running additional tools into the
wellbore thus requiring additional valuable rig time for such
purposes. For instance, to determine the initial position of the
whipstock an orientation survey tool may be run into the well. In
cased hole, a non-magnetic orientation survey tool such as a
gyroscopic survey tool may be used. In open hole, either a
gyroscopic survey tool or a magnetic compass tool may be used. Once
the initial position is known, then the pipe is rotated and the
orientation survey tool takes another survey to determine if the
whipstock is properly oriented. This process is continued until
orientation is complete. This is because that due to doglegs, deep
depths, crooked hole sections, and the like, it may not be possible
to know how much the whipstock has been rotated without use of the
subsequent surveys. If the survey tool is a wireline tool, then the
survey tool may be rigged up such that it can stay in the pipe
during rotation and send the information to the surface. However,
this may require a special rig up for the sheave wheels such that
the pipe can be manipulated while the wireline remains in the pipe.
If the survey tool is operated by slickline, or is a single shot
tool such as a battery operated tool, then a separate trip into and
out of the hole must be made for each survey because the tool must
be retrieved to determine the result. The wireline rig up takes
longer and the wireline survey tends to be more expensive than a
slickline survey. However, slickline operation requires multiple
trips.
[0006] Consequently, it would be desirable to provide a
self-orienting whipstock assembly and method that is designed to
orient itself in a known rotational orientation within the borehole
and, where adjustment from the known rotational orientation is
necessary, permits rotation of the whipstock from the known
rotational orientation to the desired rotational position without
the use of additional tools that require additional trips into the
wellbore. Those skilled in the art will appreciate the present
invention that addresses the above and other needs and
problems.
SUMMARY OF THE INVENTION
[0007] Accordingly, it is an object of the present invention to
provide an improved whipstock assembly and method.
[0008] It is yet another object of the present invention to provide
a more efficient assembly and method for orienting the whipstock
assembly downhole in a desired direction.
[0009] These and other objects, features, and advantages of the
present invention will become apparent from the drawings, the
descriptions given herein, and the appended claims.
[0010] In accordance with the present invention, a method is
provided for orientating a whipstock in a desired direction which
may comprise method steps such as the step of utilizing a wellbore
string for positioning a whipstock assembly containing the
whipstock at a desired depth within a borehole section that is
angled in a known direction. An additional step of the method may
comprise providing that the whipstock is initially free to rotate
within the borehole such that a weighted portion of the whipstock
assembly is automatically oriented by gravitational forces in a
first rotational position.
[0011] The method may further comprise affixing an orientation
section of the whipstock assembly with respect to the borehole in
the first rotational position and rotating the whipstock with
respect to the orientation section to a second rotational position.
Additional steps may comprise affixing the whipstock with respect
to the borehole in the second rotational position.
[0012] In one presently preferred embodiment, the step of affixing
the whipstock may comprise setting a packer. The method may also
comprise affixing an orientation section of the whipstock assembly
by setting an inflatable packer. More generally, the method
comprises engaging a radially moveable member which may be
characterized by an expandable and/or inflatable element and/or may
include one or more packers, slips, slips and packers, or any other
suitable gripping means with respect to the borehole to thereby
affix an orientation section of the whipstock assembly in the first
rotational position. In one preferred embodiment, the method
includes utilizing compressed gas for the step of affixing such as
setting the packer or other affixing means such as slips and the
like.
[0013] In one preferred embodiment of the invention, the method
includes a step of providing that the whipstock assembly is
rotatable independently from the wellbore string. Additional
branches from the wellbore can be produced by the steps of
releasing the whipstock assembly from the wellbore string,
initiating drilling of a first new borehole section using the
whipstock assembly, reattaching the wellbore string to whipstock
assembly, and repositioning the whipstock assembly at a second
desired depth for drilling a second new borehole section.
[0014] In another description, the method may comprise steps such
as positioning a whipstock assembly containing the whipstock at a
desired depth within a borehole, affixing an orientation section of
the whipstock assembly with respect to the borehole in a first
rotational position, and rotating the whipstock with respect to the
orientation section to a second rotational position. In one
preferred embodiment, the step of affixing the whipstock with
respect to the borehole in the second rotational position is
responsive to receiving a signal, such a signal generated at the
surface by mudpumps, with at least one transducer, such as a
pressure transducer, in the whipstock assembly. The step of
rotating may further comprise reciprocally moving a wellbore
tubular string a selected number of reciprocal strokes. Preferably,
each reciprocal stroke is translated into a specific amount of
rotation of the whipstock. A preferred feature of the present
invention includes the step of providing that the whipstock
assembly is initially freely rotatable within the borehole section
such that gravitational forces move the whipstock assembly to the
first rotational position.
[0015] The invention also comprises a whipstock assembly for use in
a wellbore that may comprise a whipstock with a guide surface, an
orientation section, a rotational connection between the whipstock
and the orientation section; and one or more radially moveable
members secured to the orientation section. The one or more
radially moveable members may be radially moveable from a
nonengaged position with respect to the wellbore to an engaged
position with respect to the wellbore for affixing the orientation
section in the first rotational position.
[0016] As well, one or more second radially moveable members may be
secured to the whipstock. Likewise the one or more second radially
moveable members secured to the whipstock may be radially moveable
from a nonengaged position with respect to the wellbore to an
engaged position with respect to the wellbore for affixing the
whipstock in the second selectable rotational position.
[0017] A mechanical motion translator may be provided for
translating reciprocal movement of the wellbore string into
rotational movement between whipstock and the orientation section.
A transducer such as a pressure transducer may be attached to the
whipstock assembly for receiving a signal and a container may be
provided for compressed gas.
[0018] In a preferred embodiment, one or more bearings are
preferably mounted with respect to the whipstock assembly such that
the whipstock assembly is rotatable with respect to the wellbore.
One side of the whipstock assembly comprises a heavy side. Due the
bearings, the heavy side may be automatically positioned by gravity
in the first rotational position.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] A more complete understanding of the invention and many of
the attendant advantages thereto will be readily appreciated as the
same becomes better understood by reference to the following
detailed description when considered in conjunction with the
accompanying drawings wherein corresponding reference characters
indicate corresponding parts throughout the drawing and
wherein:
[0020] FIG. 1 is an elevational view, partially in section, of an
embodiment of a self orienting whipstock assembly in accord with
the present invention;
[0021] FIG. 2 is a cross-sectional view, partially in section,
along lines 2-2 of FIG. 1 showing how the whipstock is
automatically oriented in an angled borehole;
[0022] FIG. 3 is an elevational view, partially in section, of the
self orienting whipstock assembly of FIG. 1 with the lower packer
or slips expanded to anchor the assembly in a first rotational
position;
[0023] FIG. 4 is an elevational view, partially in section, with a
spring of a mechanical translation mechanism compressed to thereby
change reciprocal movement of the wellbore string into rotational
movement of the whipstock;
[0024] FIG. 5 is an elevational view, partially in section, with
the upper packer or slips expanded to anchor the whipstock in the
desired rotational position;
[0025] FIG. 6 is an elevational view, partially in section, of the
running tool being removed such as by shearing retaining pins;
[0026] FIG. 7 is an elevational view, partially in section, with
the whipstock directing a bit or mill in the desired direction to
form a new borehole;
[0027] FIG. 8 is an elevational view, partially in section, showing
the whipstock assembly adjacent a newly drilled wellbore after the
drilling or milling wellbore string has been removed;
[0028] FIG. 9 is an elevational view, partially in section, showing
the whipstock assembly being retrieved for removal or for
repositioning to drill another borehole; and
[0029] FIG. 10 is an elevational view, showing a slotted sleeve
used for mechanical translation of reciprocal movement of the
wellbore string into rotational movement of the whipstock.
BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0030] Referring now to the drawings and, more particularly, to
FIG. 1 there is shown a self orienting whipstock assembly 10 in
accord with the present invention. Whipstock assembly 10 is mounted
to be free for rotation within wellbore 12. Wellbore 12 may be a
cased hole or also an open hole, i.e., casing may have been set at
the depth of interest or not. To provide free rotation, whipstock
assembly 10 may, for instance, be mounted on bearings such as upper
bearing 14, middle bearings 16 and 18, and lower bearing 20. The
bearing design variations may include a different number of
bearings, different locations, types of bearing, and the like as
may be changed as desired to effect free rotation of whipstock
assembly 10 within wellbore 12.
[0031] Because whipstock assembly 10 is free to rotate within
borehole 12, and because very few boreholes are perfectly vertical,
assembly 10 will automatically rotate due to gravitational forces
as shown in FIG. 2. In the present design, whipstock 22 provides a
shape that has considerable extra weight on one side so that
whipstock 22 will cause the whipstock assembly 10 to rotate so that
whipstock 22 is at bottom most or low side 24 of borehole 12. Thus,
whipstock 22 will move away from high side 26 of borehole 12.
Whipstock face 28 is seen to be shaped to form a concave guide
surface for guiding the mill or bit. Other face configurations
could also be used as desired for guiding the desired type of
drilling/milling device.
[0032] While the present invention is ideal for use where it is
desirable to conveniently determine the initial rotational position
of the whipstock assembly without the need for orientation surveys
such as in a deep, deviated wellbores, in some cases knowing the
initial position of the whipstock may be unnecessary. Even in a
purely vertical borehole 12, it may be desirable to be able to
rotate the whipstock from an unknown position by a known amount. To
give one example, multiple branches may be made for forming an
"umbrella" configuration of boreholes where the initial orientation
is not necessary but it is highly desirable to have the multiple
boreholes oriented by a known spaced rotational amount. The present
invention is also ideal for providing this service without the need
for additional orientation surveys by means discussed in detail
subsequently. Thus, although the present invention is highly suited
to use in deviated wellbores to thereby save time and cost, the
present invention is not intended to be limited to use only in
deviated wellbores. Moreover, it will be understood that such terms
as "up," "down," "vertical," and the like, are made with reference
to the drawings and/or the earth and that the devices may not be
arranged in such positions at all times depending on variations in
operation, transportation, and the like. It will also be understood
that the drawings are intended to describe the concepts of the
invention so that the presently preferred embodiments of the
invention will be plainly disclosed to one of skill in the art but
are not intended to be manufacturing level drawings or renditions
of final products and may include simplified conceptual views as
desired for easier and quicker understanding or explanation of the
invention. As well, the relative size of the components may be
greatly different from that shown. Moreover, while an angled
borehole 12, with respect to the vertical, is shown in FIG. 1 for
purposes of explanation, it will be understood that the remainder
of views which are shown to be vertically oriented may or may not
involve angled boreholes, i.e., deviated boreholes.
[0033] Referring back to FIG. 1, whipstock assembly 10 comprises an
upper section referred to herein as whipstock 22 and a lower
section referred to as orientation section 30. In this embodiment
of the invention, whipstock 22 is connected to orientation section
30 by mandrel 32. Mandrel 32 is interconnected as discussed
subsequently, so that at least initially, whipstock 22 and
orientation section 30 are locked so as to rotate together.
[0034] Therefore, referring now to FIG. 3, whipstock assembly 10 is
positioned at the desired depth and the tool has automatically
rotated so that whipstock 22 is in a first rotational position on
the bottom side of the wellbore as shown in FIG. 2. The orientation
of the wellbore is normally tracked during drilling so that the
angle and azimuth of the borehole at any depth are known thereby
permitting the operator to determine the orientation that whipstock
22 will automatically assume at the depth where the kickoff of the
new borehole is to be. Thus after positioning whipstock assembly 10
at this depth, lower clamping member 34 is activated as shown so as
to expand radially outwardly to grip or engage borehole 12. Lower
clamping member 34 may be a packer, slips, or a combination of
slips and packer. Clamping member 34 may be one or more elements
that expand or move radially outwardly to grippingly engage
borehole 12 and affix orientation section 30 in a known first
rotational position. In a presently preferred embodiment, clamping
member 34 is an inflatable packer.
[0035] It may happen that in the first rotational position,
whipstock 22 is already at the desired rotational position which
will guide the bit or mill in the desired direction intended for
the new borehole. However, normally this may not be the case. It
will therefore typically be necessary to rotate whipstock 22 with
respect to orientation section 30 by an amount which the operator
will know because he already knows the desired direction of the new
borehole and he knows the first rotational position at which
whipstock 22 will be automatically oriented in wellbore 12 prior to
and just after activating clamping member 34.
[0036] FIG. 4 illustrates how whipstock 22 is rotated with respect
to orientation section 30. In a presently preferred embodiment,
this action is accomplished by using a mechanical motion translator
to translate reciprocal movement of wellbore string 55 (see FIG. 1
and FIG. 3) as indicated by arrow 36 in a downward direction. This
action compresses spring 39 as indicated in FIG. 4. Referring back
to FIG. 3, it is seen that spring 39 is uncompressed. This
reciprocal compressing--uncompressin- g action moves mandrel 32
downwardly as indicated in FIG. 4 from the position of mandrel 32
as shown in FIG. 3. Attached to mandrel 32 is key 38. Key 38 moves
through slotted sleeve 40. A projection of slotted cylindrical
sleeve 40 is shown in FIG. 10 as a plane surface 42 with grooves 44
and cam surfaces 46. Key 38 then moves as indicated by arrows and
numbers in FIG. 10. Reciprocal movement of wellstring 55 as
indicated by arrow 36 causes key 38 to follow grooves 44 and cam
surfaces 46 thereby cause key 38 and, therefore, mandrel 32 to
rotate. Mandrel 32 is attached to whipstock 22 so that whipstock 22
therefore rotates with respect to orientation section 30. Depending
on the spacing of the grooves, the amount and direction of rotation
for each reciprocal stroke is known. For instance, if it desired to
rotate ninety degrees in the direction of rotation, and each
reciprocal stroke produces thirty degrees of rotation of whipstock
22, then the operator strokes the whipstock assembly three times.
Generally, if the whipstock is within about thirty degrees of the
desired orientation for the new wellbore section, then that is
sufficiently accurate for most applications. However, greater
accuracy could be obtained with grooves having smaller spacings
therebetween. As well, a specific slotted sleeve 40 could be tailor
made for a specific application if even more accuracy was
desired.
[0037] It will be seen that mandrel 32 also rotationally locks
whipstock 22 and orientation section 30 together due to the
position of mandrel key 38 in grooves 44 which are biased to remain
in position within grooves 44 by spring 39. After lower clamping
member 34 is activated, spring 39 can be compressed due to the
affixed position of orientation section 30 to thereby select the
desired orientation of whipstock 22. Thus, with orientation section
30 affixed wellbore 12, relative reciprocal or longitudinal
movement between whipstock 22 and orientation section 30 is
possible by reciprocal movement of wellbore string 55 to thereby
also rotate whipstock 22 with respect to orientation section
30.
[0038] In FIG. 5, whipstock 22 has been oriented to the desired
position such as by one or more reciprocal strokes as discussed
above. At this time, upper clamping member 48 is activated to
thereby lock whipstock 22 into a second desired rotational
orientation. Upper clamping member 48 may be a packer, slips, or a
combination of slips and packer. Upper clamping member 48 may be
one or more elements that expand or move radially outwardly to
grippingly engage wellbore 12 and affix orientation section
whipstock 22 in the second rotational position, which is the
desired position. Due to engagement of upper clamping member 48,
pressure applied to whipstock 22 will no longer move whipstock 22
downwardly so that further rotation of whipstock 22 is prevented.
In a presently preferred embodiment, upper clamping member 48 is an
inflatable packer.
[0039] In FIG. 6, running tool 50 is removed by pulling upwardly on
the wellbore string 55 to shear pins, bolts or disks 52. Other
connections and means for releasing the whipstock may be used such
as connections which are used to release other types of downhole
tools in the wellbore. Thus, shear pins, disks, or bolts are
provided as an example only of one method of releasing the wellbore
string and whipstock assembly 12. Running tool 50 may preferably
include bearings or rotatable connection 53 so as to permit
whipstock assembly 10 to rotate freely with respect to wellbore
string 55. Shear pins, bolts, or disks 52 could also be connect to
a rotational connection to effect this purpose. In any case,
whipstock assembly 10 is preferably freely rotatable with respect
to wellbore string 55 and may be released therefrom when
desired.
[0040] In FIG. 7, a new wellbore string 54 is run into wellbore 12
with bit or mill 56 to open a window in the casing or initiate
drilling as the situation may call for. Whipstock 22 guides bit or
mill 56 in the desired direction for the new borehole or casing
window.
[0041] In FIG. 8, new lateral borehole 58 has been drilled and
wellbore string 54 is removed. Upper connector 60, which may be of
numerous types, is available for connection to remove or relocate
whipstock assembly 10 once upper and lower clamping members 48 and
34, respectively, have been released. In FIG. 9, pulling tool 62
engages upper connector 60 for retrieving whipstock assembly 10. As
will be noted upper and lower clamping member 48 and 34 have been
released prior to retrieval. If pulling tool 62 is used for
relocating whipstock assembly 10 elsewhere to produce another new
wellbore, then pulling tool 62 will be designed to release from
whipstock assembly 10 as discussed above and may use shear pins,
bolts, or other means such as tension responsive bolts and sleeves,
actuators that respond to a pressure switch as do the valves
discussed hereinafter, or other suitable means for connecting to
and/or releasing whipstock assembly 10.
[0042] Various means may be used for engaging and releasing upper
and lower clamping members 48 and 34. In one embodiment, a liquid
nitrogen reservoir 64 may be used with associated valves 66 and 68
for applying pressure from liquid nitrogen reservoir 64 to the
respective upper and lower clamping members 48 and 34. One or more
pressure transducers and controls, such as transducers 70 and 72
may be used for controlling the valves. For instance each
transducer 70 may include a logic circuit that responds to a
particular signal to open or close the respective valve in response
to a particular code of pressure pulses that may be produced, for
example only, by cycling the surface mud pumps. High temperature
lithium batteries may be encapsulated for powering the logic
circuit, such as a microprocessor and for controlling the valves.
For example, once the pressure signal for activating the lower
clamping member is received and recognized by transducers such as
70 and 72, which transducer packages may also include a
microprocessor and batteries, then valve 66 may be opened for a
given period of time so that enough nitrogen is taken from
reservoir 64 into lower clamping member 34 which may be an
inflatable/expandable packer. A different signal could be used for
upper clamping member 48. Various methods could be provided for
deflation as well. For instance, a different signal could be used
and valves 66 and 68 could be three way valves to bleed off
pressure into wellbore 12 and/or annulus 74. Mechanical means such
as internal sliding sleeves could be used to shear pins. The
sliding sleeves would shear the pins when a selected tension is
applied to the whipstock assembly 10 by means of pulling tool 62,
to allow the nitrogen to bleed off through sleeve ports into
wellbore 12 and/or annulus 74. The above discussion related to
activating upper and lower clamping members 34 and 48 is given as
an example only because numerous different methods are available
for activating clamping members such as packers, plugs, and slips
including mechanical, explosive, electrical means.
[0043] In summary, whipstock assembly 10 is run into wellbore 12 to
the desired depth at which the new wellbore is to be kicked off
from wellbore 12. Whipstock 10 automatically orients itself to the
low side 24 of wellbore 12 as shown in FIG. 2 which position is
known beforehand to the operator as discussed above. Lower clamping
member 34 affixes orientation section 30 with respect to wellbore
12 in the first rotational position. The wellbore string including
running tool 50 is reciprocated to thereby rotate whipstock 22 to
the desired second rotational postion. Upper clamping member 48 is
then activated to affix whipstock 22 in position. Running tool 50
is removed and the milling or drilling assembly is then used to
kickoff new wellbore 58. Once completed, whipstock assembly 10 can
be retrieved by releasing upper and lower clamping members 48 and
34 after reconnecting with whipstock assembly 10 using retrieving
tool 62. Retrieving tool 62 may be used to remove whipstock
assembly 10 from wellbore 12 or relocate whipstock assembly 10
elsewhere in borehole 12 or new wellbore 58 to kick off another
wellbore.
[0044] While the discussion above relates to using a wellbore
string for running whipstock assembly 10 into wellbore 12 such as a
pipe, drilling, or tubing string, other types of wellbore strings
such as sucker rods, wireline, or slickline could also be used.
Different adaptations could then be made as appropriate. For
instance with wireline, electrical power is generally available and
could be used, for instance to activate the clamping members,
rotate the whipstock such as with an electric motor, and the like.
Alternatively wireline or slickline jars or weight sections could
be used to produce a reciprocal movement for rotating whipstock 22
as discussed above. As stated above, other types of connectors for
running tool and pulling tool 62 could be used.
[0045] Thus, numerous variations of the above method are possible,
some of which have already been described. Therefore, it will be
understood that many additional changes in the details, materials,
steps and arrangement of parts, may be made by those skilled in the
art within the principle and scope of the invention as expressed in
the appended claims.
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