U.S. patent application number 09/518122 was filed with the patent office on 2002-06-20 for pipe running tool.
Invention is credited to Boyadjieff, George, Eidem, Brian L, Juhasz, Daniel, Rijzingen, Hans Van.
Application Number | 20020074132 09/518122 |
Document ID | / |
Family ID | 22405604 |
Filed Date | 2002-06-20 |
United States Patent
Application |
20020074132 |
Kind Code |
A1 |
Juhasz, Daniel ; et
al. |
June 20, 2002 |
PIPE RUNNING TOOL
Abstract
A pipe running tool for use in an oil drilling system and the
like comprises a lower drive shaft adapted to engage a drive shaft
of a top drive assembly for rotation therewith. The pipe running
tool further includes a lower pipe engagement assembly which is
driven to rotate by the lower drive shaft, and is designed to
releasably engage a pipe segment in such a manner to substantially
prevent relative rotation between the two. Thus, when the lower
pipe engagement assembly is actuated to securely hold a pipe
segment, the top drive assembly may be actuated to rotate the top
drive output shaft, which causes the lower drive shaft and lower
pipe engagement assembly to rotate, which in turn rotates the pipe
segment.
Inventors: |
Juhasz, Daniel;
(Westminister, CA) ; Boyadjieff, George; (Villa
Park, CA) ; Eidem, Brian L; (Cerritos, CA) ;
Rijzingen, Hans Van; (Etten-leur, NL) |
Correspondence
Address: |
Christie Parker & Hale LLP
P O Box 7068
Pasadena
CA
91109-7068
US
|
Family ID: |
22405604 |
Appl. No.: |
09/518122 |
Filed: |
March 3, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60122915 |
Mar 5, 1999 |
|
|
|
Current U.S.
Class: |
166/380 ;
166/77.51 |
Current CPC
Class: |
E21B 19/086 20130101;
E21B 19/165 20130101; E21B 19/10 20130101; E21B 19/07 20130101;
E21B 19/164 20130101; E21B 19/00 20130101; E21B 19/14 20130101;
E21B 19/02 20130101; E21B 19/16 20130101 |
Class at
Publication: |
166/380 ;
166/77.51 |
International
Class: |
E21B 019/16 |
Claims
What is claimed is:
1. A pipe running tool mountable on a rig for use in handling pipe
segments and for engaging the pipe segments to a string of pipe,
the pipe running tool comprising: a top drive assembly adapted to
be connected to the rig for vertical displacement of the top drive
assembly relative to the rig, the top drive assembly including a
drive shaft, the top drive assembly being operative to rotate the
drive shaft; and a lower pipe engagement assembly including a
central passageway sized for receipt of the pipe segment, the lower
pipe engagement assembly including a powered pipe engaging
mechanism that is selectively driven into a pipe engagement
position to forcibly yet releasably engage the pipe segment and
substantially prevent relative rotation therebetween, the lower
pipe engagement assembly being in communication with the drive
shaft, whereby actuation of the top drive assembly causes the lower
pipe engagement assembly to rotate.
2. The pipe running tool of claim 1, further including a hoist
mechanism connected to the lower pipe engagement assembly and
operative to hoist a pipe segment into the central passageway of
the lower pipe engagement assembly.
3. The pipe running tool of claim 2, wherein the hoist mechanism
comprises an axle journaled to the lower pipe engagement member, a
pair of pulleys rotatably mounted to the axle, and a gear connected
to the axle, whereby the gear may be coupled to a drive system for
rotating the axle.
4. The pipe running tool of claim 1, wherein the lower pipe
engagement assembly comprises a spider.backslash.elevator.
5. The pipe running tool of claim 1, wherein the lower pipe
engagement assembly is powered by one of a hydraulic system and a
pneumatic system.
6. The pipe running tool of claim 5, wherein the lower pipe
engagement assembly comprises a generally cylindrical housing
defining a central passageway, and a plurality of slips disposed
within the bowl and displaceable radially inwardly to engage a
casing segment extending through the opening.
7. The pipe running tool of claim 1, further including a block
connected to the top drive assembly and adapted for engaging a
plurality of cables connected to the rig.
8. The pipe running tool of claim 7, wherein the drive members
comprise hydraulic lift cylinders.
9. A pipe running tool mountable on a rig and designed for use in
handling pipe segments and for engaging pipe segments to a pipe
string, the pipe running tool comprising: a top drive assembly
adapted to be connected to the rig, the top drive assembly
including a top drive output shaft, the top drive assembly being
operative to rotate the drive shaft; a lower drive shaft coupled to
the top drive output shaft and comprising an adjustable segment
that is selectively adjustable to adjust the length of the second
drive shaft; a lower pipe engagement assembly including a central
passageway sized for receipt of the pipe segment, the lower pipe
engagement assembly being operative to releasably grasp the pipe
segment, the lower pipe engagement assembly being connected to the
second drive shaft, whereby actuation of the top drive assembly
causes the lower pipe engagement assembly to rotate; and means for
applying a force to the second shaft to cause the length of the
adjustable segment to be shortened.
10. The pipe running tool of claim 9, wherein the means for
applying comprises a load compensator in the form of a pair of
hydraulic cylinders.
11. The pipe running tool of claim 9, wherein the lower pipe
engagement assembly is actuated by one of a hydraulic system and a
pneumatic system.
12. The pipe running tool of claim 9, wherein the lower pipe
engagement assembly comprises a generally cylindrical housing
defining a central passage, and a plurality of slips disposed
within the housing and displaceable radially inwardly to engage a
casing segment extending through the passage.
13. The pipe running tool of claim 9, further including a block
connected to the top drive assembly and adapted for engaging a
plurality of cables connected to the rig to selectively raise and
lower the top drive assembly.
14. A pipe running tool mountable on a rig and designed for use in
connection with a top drive assembly adapted to be connected to the
rig for vertical displacement of the top drive assembly relative to
the rig, the top drive assembly including a drive shaft, the top
drive assembly being operative to rotate the drive shaft, the pipe
running tool comprising: a lower pipe engagement assembly
comprising: a housing defining a central passageway sized for
receipt of a pipe segment, the housing being coupled to the top
drive assembly for rotation therewith; a plurality of slips
disposed within the housing and displaceable between disengaged and
engaged positions; and a powered system connected to the respective
slips and operative to selectively drive the slips between the
disengaged and engaged positions.
15. The pipe running tool of claim 14, further including a hoist
mechanism connected to the lower pipe engagement assembly and
operative to hoist a pipe segment into the central passageway of
the lower pipe engagement assembly.
16. The pipe running tool of claim 15, wherein the hoist mechanism
comprises an axle journaled to the lower pipe engagement member, a
pair of pulleys rotatably mounted to the axle, and a gear connected
to the axle, whereby the gear may be coupled to a drive system for
rotating the axle.
17. The pipe running tool of claim 14, wherein the powered system
comprises one of a hydraulic and pneumatic system.
18. The pipe running tool of claim 14, further including a block
connected to the top drive assembly and adapted for engaging a
plurality of cables connected to the rig.
19. In a system for assembling a pipe string comprising a top drive
assembly, a lower pipe engagement assembly coupled to the top drive
assembly for rotation therewith and operative to releasably engage
a pipe segment, and a load compensator operative to raise the lower
pipe engagement assembly relative to the top drive assembly, a
method for threadedly engaging a pipe segment with a pipe string,
comprising the steps of: actuating the lower pipe engagement
assembly to releasably engage a pipe segment; lowering the top
drive assembly to bring the pipe segment into contact with the pipe
string; monitoring the load on the pipe string; actuating the load
compensator to raise the pipe segment a selected distance relative
to the pipe string, if the load on the pipe string exceeds a
predetermined threshold value; and actuating the top drive assembly
to rotate the pipe segment to threadedly engage the pipe segment
and pipe string.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application is based on provisional patent application
serial No. 60/122,915 filed Mar. 5, 1999.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to well drilling operations and, more
particularly, to a device for assisting in the assembly of pipe
strings, such as casing strings, drill strings and the like.
[0004] 2. Description of the Related Art
[0005] The drilling of oil wells involves assembling drill strings
and casing strings, each of which comprises a plurality of
elongated, heavy pipe segments extending downwardly from an oil
drilling rig into a hole. The drill string consists of a number of
sections of pipe which are threadedly engaged together, with the
lowest segment (i.e., the one extending the furthest into the hole)
carrying a drill bit at its lower end. Typically, the casing string
is provided around the drill string to line the well bore after
drilling the hole and ensure the integrity of the hole. The casing
string also consists of a plurality of pipe segments which are
threadedly coupled together and formed with through passages sized
to receive the drill string and/or other pipe strings.
[0006] The conventional manner in which plural casing segments are
coupled together to form a casing string is a labor-intensive
method involving the use of a "stabber" and casing tongs. The
stabber is manually controlled to insert a segment of casing into
the upper end of the existing casing string, and the tongs are
designed to engage and rotate the segment to threadedly connect it
to the casing string. While such a method is effective, it is
cumbersome and relatively inefficient because the procedure is done
manually. In addition, the casing tongs require a casing crew to
properly engage the segment of casing and to couple the segment to
the casing string. Thus, such a method is relatively
labor-intensive and therefore costly. Furthermore, using casing
tongs requires the setting up of scaffolding or other like
structures, and is therefore inefficient.
[0007] Others have proposed a casing running tool for assembling
casing strings which utilizes a conventional top drive assembly.
The tool includes a pivotable manipulator which is designed to
engage a pipe segment and raise the pipe segment up into a power
assist spider, which relies on gravity to hold the pipe segment.
The spider is coupled to the top drive and may be rotated by it.
Thus, the pipe segment may be brought into contact with a casing
string and the top drive activated to rotate the casing segment and
threadedly engage it with the casing string.
[0008] While such a system provides benefits over the more
conventional systems used to assemble casing strings, such a system
suffers from shortcomings. One such shortcoming is that the casing
segment may not be sufficiently engaged by the power assist spider
to properly connect the casing segment with the casing string. In
addition, the system fails to provide any means for effectively
controlling the load applied to the threads at the bottom of the
casing segment. Without the ability to control the load on the
threads, cross-threading may occur, resulting in stripped threads
and a useless casing segment.
[0009] Accordingly, it will be apparent to those skilled in the art
that there continues to be a need for a device for use in a
drilling system which utilizes an existing top drive assembly to
efficiently assemble casing and/or drill strings, and which
positively engages a pipe segment to ensure proper coupling of the
pipe segment to a pipe string. The present invention addresses
these needs and others.
SUMMARY OF THE INVENTION
[0010] Briefly, and in general terms, the present invention is
directed to a pipe running tool for use in drilling systems and the
like to assemble casing and/or drill strings. The pipe running tool
is coupled to an existing top drive assembly which is used to
rotate a drill string, and includes a powered elevator that is
powered into an engaged position to securely engage a pipe segment,
for example, a casing segment. Because the elevator is powered into
the engaged position, the pipe segment may be properly coupled to
an existing pipe string using the top drive assembly.
[0011] The system of the present invention in one illustrative
embodiment is directed to a pipe running tool mountable on a rig
and including: a top drive assembly adapted to be connected to the
rig for vertical displacement of the top drive assembly relative to
the rig, the top drive assembly including a drive shaft, the top
drive assembly being operative to rotate the drive shaft; and a
lower pipe engagement assembly including a central passageway sized
for receipt of the pipe segment, the lower pipe engagement assembly
including a powered engagement device that is powered to an engaged
position to securely and releasably grasp the pipe segment, the
lower pipe engagement assembly being in communication with the
drive shaft, whereby actuation of the top drive assembly causes the
lower pipe engagement assembly to rotate.
[0012] In another illustrative embodiment, the present invention is
directed to a method of assembling a pipe string, including the
steps of: actuating a lower pipe engagement assembly to releasably
engage a pipe segment; lowering a top drive assembly to bring the
pipe segment into contact with a pipe string; monitoring the load
on the pipe string; actuating a load compensator to raise the pipe
segment a selected distance relative to the pipe string, if the
load on the pipe string exceeds a predetermined threshold value;
and actuating the top drive assembly to rotate the pipe segment to
threadedly engage the pipe segment and pipe string.
[0013] Other features and advantages of the present invention will
become apparent from the following detailed description, taken in
conjunction with the accompanying drawings which illustrate, by way
of example, the features of the present invention.
DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is an elevated side view of a drilling rig
incorporating a pipe running tool according to one illustrative
embodiment of the present invention;
[0015] FIG. 2 is a side view, in enlarged scale, of the pipe
running tool of FIG. 1;
[0016] FIG. 3 is a cross-sectional view taken along the line 3-3 of
FIG. 2;
[0017] FIG. 4 is a cross-sectional view taken along the line 4-4 of
FIG. 2;
[0018] FIG. 5A is a cross-sectional view taken along the line 5-5
of FIG. 4 and showing a spider.backslash.elevator in a disengaged
position;
[0019] FIG. 5B is a cross-sectional view similar to FIG. 5A and
showing the spider.backslash.elevator in an engaged position;
[0020] FIG. 6 is a block diagram of components included in one
illustrative embodiment of the invention; and
[0021] FIG. 7 is a side view of another illustrative embodiment of
the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] In the following detailed description, like reference
numerals will be used to refer to like or corresponding elements in
the different figures of the drawings. Referring now to FIGS. 1 and
2, there is shown a pipe running tool 10 depicting one illustrative
embodiment of the present invention, which is designed for use in
assembling pipe strings, such as drill strings, casing strings, and
the like. The pipe running tool 10 comprises, generally, a frame
assembly 12, a rotatable shaft 14, and a lower pipe engagement
assembly 16 that is coupled to the rotatable shaft for rotation
therewith. The pipe engagement assembly is designed for selective
engagement of a pipe segment 11 (FIGS. 1,2, and 5A) to
substantially prevent relative rotation between the pipe segment
and the pipe engagement assembly. The rotatable shaft 14 is
designed for coupling with a top drive output shaft from an
existing top drive, such that the top drive, which is normally used
to rotate a drill string to drill a well hole, may be used to
assemble a pipe string, for example, a casing string or a drill
string, as is described in greater detail below.
[0023] The pipe running tool 10 is designed for use, for example,
in a well drilling rig 18. A suitable example of such a rig is
disclosed in U.S. Pat. No. 4,765,401 to Boyadjieff, which is
expressly incorporated herein by reference as if fully set forth
herein. As shown in FIG. 1, the rig includes a frame 20 and a pair
of guide rails 22 along which a top drive assembly, generally
designated 24, may ride for vertical movement relative to the rig.
The top drive assembly is preferably a conventional top drive used
to rotate a drill string to drill a well hole, as is described in
U.S. Pat. No. 4,605,077 to Boyadjieff, which is expressly
incorporated herein by reference. The top drive assembly includes a
drive motor 26 and a top drive output shaft 28 extending downwardly
from the drive motor, with the drive motor being operative to
rotate the drive shaft, as is conventional in the art. The rig
defines a drill floor 30 having a central opening 32 through which
a drill string and/or casing string 34 is extended downwardly into
a well hole.
[0024] The rig 18 also includes a flush-mounted spider 36 that is
configured to releasably engage the drill string and/or casing
string 34 and support the weight thereof as it extends downwardly
from the spider into the well hole. As is well known in the art,
the spider includes a generally cylindrical housing which defines a
central passageway through which the pipe string may pass. The
spider includes a plurality of slips which are located within the
housing and are selectively displaceable between disengaged and
engaged positions, with the slips being driven radially inwardly to
the respective engaged positions to tightly engage the pipe segment
and thereby prevent relative movement or rotation of the pipe
segment and the spider housing. The slips are preferably driven
between the disengaged and engaged positions by means of a
hydraulic or pneumatic system, but may be driven by any other
suitable means.
[0025] Referring primarily to FIG. 2, the pipe running tool 10
includes the frame assembly 12, which comprises a pair of links 40
extending downwardly from a link adapter 42. The link adapter
defines a central opening 44 through which the top drive output
shaft 28 may pass. Mounted to the link adapter on diametrically
opposed sides of the central opening are respective upwardly
extending, tubular members 46 (FIG. 1), which are spaced a
predetermined distance apart to allow the top drive output shaft 28
to pass therebetween. The respective tubular members connect at
their upper ends to a rotating head 48, which is connected to the
top drive assembly 24 for movement therewith. The rotating head
defines a central opening (not shown) through which the top drive
output shaft may pass, and also includes a bearing (not shown)
which engages the upper ends of the tubular members and permits the
tubular members to rotate relative to the rotating head body, as is
described in greater detail below.
[0026] The top drive output shaft 28 terminates at its lower end in
an internally splined coupler 52 which is engaged to an upper end
of the lower drive shaft 14 (not shown) which is formed to
complement the splined coupler for rotation therewith. Thus, when
the top drive output shaft 28 is rotated by the top drive motor 26,
the lower drive shaft 14 is also rotated. It will be understood
that any suitable interface may be used to securely engage the top
and lower drive shafts together.
[0027] In one illustrative embodiment, the lower drive shaft 14 is
connected to a conventional pipe handler, generally designated 56,
which may be engaged by a suitable torque wrench (not shown) to
rotate the lower drive shaft and thereby make and break connections
that require very high torque, as is well known in the art.
[0028] The lower drive shaft 14 is also formed with a splined
segment 58, which is slidably received in an elongated, splined
bushing 60 which serves as an extension of the lower drive shaft.
The drive shaft and bushing are splined to provide for vertical
movement of the shaft relative to the bushing, as is described in
greater detail below. It will be understood that the splined
interface causes the bushing to rotate when the lower drive shaft
rotates.
[0029] The pipe running tool 10 further includes the lower pipe
engagement assembly 16, which in one embodiment comprises a torque
transfer sleeve 62 which is securely connected to the lower end of
the bushing 60 for rotation therewith. The torque transfer sleeve
is generally annular and includes a pair of upwardly projecting
arms 64 on diametrically opposed sides of the sleeve. The arms are
formed with respective horizontal through passageways (not shown)
into which are mounted respective bearings (not shown) which serve
to journal a rotatable axle 70 therein, as described in greater
detail below. The transfer sleeve connects at its lower end to a
downwardly extending torque frame 72 in the form of a pair of
tubular members 73, which in turn is coupled to a
spider.backslash.elevator 74 which rotates with the torque frame.
It will be apparent that the torque frame may take many, such as a
plurality of tubular members, a solid body, or any other suitable
structure.
[0030] The spider.backslash.elevator 74 is preferably powered by a
hydraulic or pneumatic system, or alternatively by an electric
drive motor or any other suitable powered system. In the embodiment
disclosed, the spider.backslash.elevator includes a housing 75
which defines a central passageway 76 through which the pipe
segment 11 may pass. The spider.backslash.elevator also includes a
pair of hydraulic or pneumatic cylinders 77 with displaceable
piston rods 78 (FIGS. 5A and 5B) which are connected through
suitable pivotable linkages 79 to respective slips 80. The linkages
are pivotally connected to both the top ends of the piston rods and
to the top ends of the slips. The slips include generally planar
front gripping surfaces 82, and specially contoured rear surfaces
84 which are designed with such a contour to cause the slips to
travel between respective radially outwardly disposed, disengaged
positions, and radially inwardly disposed, engaged positions. The
rear surfaces of the slips travel along respective downwardly and
radially inwardly projecting guiding members 86 which are
complementarily contoured and securely connected to the spider
body. The guiding members cooperate with the cylinders and linkages
to cam the slips radially inwardly and force the slips into the
respective engaged positions. Thus, the cylinders (or other
actuating means) may be empowered to drive the piston rods
downwardly, causing the corresponding linkages to be driven
downwardly and therefore force the slips downwardly. The surfaces
of the guiding members are angled to force the slips radially
inwardly as they are driven downwardly to sandwich the pipe segment
11 between them, with the guiding members maintaining the slips in
tight engagement with the pipe segment. To release the pipe segment
11, the cylinders 76 are operated in reverse to drive the piston
rods upwardly, which draws the linkages upwardly and retracts the
respective slips back to their disengaged positions to release the
pipe segment. The guiding members are preferably formed with
respective notches 81 which receive respective projecting portions
83 of the slips to lock the slips in the disengaged position (FIG.
5A).
[0031] The spider.backslash.elevator 74 further includes a pair of
diametrically opposed, outwardly projecting ears 88 formed with
downwardly facing recesses 90 sized to receive correspondingly
formed, cylindrical members 92 at the bottom ends of the respective
links 40, and thereby securely connect the lower ends of the links
to the spider.backslash.elevator. The ears may be connected to an
annular sleeve 93 which is received over the housing 75, or may be
formed integral with the housing.
[0032] In one illustrative embodiment, the pipe running tool 10
includes a load compensator, generally designated 94. The load
compensator preferably is in the form of a pair of hydraulic,
double rodded cylinders 96, each of which includes a pair of piston
rods 98 that are selectively extendable from, and retractable into,
the cylinder. The upper rods connect to a compensator clamp 100,
which in turn is connected to the lower drive shaft 14, while the
lower rods extend downwardly and connect at the respective lower
ends to a pair of ears 102 which are securely mounted to the
bushing 60. The hydraulic cylinders may be actuated to draw the
bushing upwardly relative to the lower drive shaft 14 by applying a
pressure to the cylinders which causes the upper piston rods to
retract into the respective cylinder bodies, with the splined
interface between the bushing and lower drive shaft allowing the
bushing to be displaced vertically relative to the shaft. In that
manner, the pipe segment 11 carried by the
spider.backslash.elevator 74 may be raised vertically to relieve a
portion or all of the load applied to the pipe segment 11, as is
described in greater detail below. As is shown in FIG. 2, the lower
rods are at least partially retracted, resulting in the majority of
the load from the pipe running tool 10 is assumed by the top drive
output shaft 28. In addition, when a load above a preselected
maximum is applied to the pipe segment 11, the cylinders 96 will
automatically react the load to prevent the entire load from being
applied to the threads of the pipe segment.
[0033] The pipe running tool 10 still further includes a hoist
mechanism, generally designated 104, for hoisting a pipe segment
upwardly into the spider.backslash.elevator 74. The hoist mechanism
is disposed off-axis and includes a pair of pulleys 106 carried by
the axle 70, the axle being journaled into the bearings in
respective through passageways formed in the arms 64. The hoist
mechanism also includes a gear drive, generally designated 108,
that may be selectively driven by a hydraulic motor 111 or other
suitable drive system to rotate the axle and thus the pulleys. The
hoist may also include a brake 115 to prevent rotation of the axle
and therefore of the pulleys and lock them in place, as well as a
torque hub 116. Therefore, a pair of chains, cables, or other
suitable, flexible means may be run over the respective pulleys,
extended through a chain well 113, and engaged to the pipe segment
11, and the axle is then rotated by a suitable drive system to
hoist the pipe segment vertically and up into position with the
upper end of the pipe segment 11 extending into the
spider.backslash.elevator 74.
[0034] The pipe running tool 10 preferably further includes an
annular collar 109 which is received over the links 40 and which
maintains the links locked to the ears 88 and prevents the links
from twisting and/or winding.
[0035] In use, a work crew may manipulate the pipe running tool 10
until the upper end of the tool is aligned with the lower end of
the top drive output shaft 28. The pipe running tool 10 is then
raised vertically until the splined coupler 52 at the lower end of
the top drive output shaft is engaged to the upper end of the lower
drive shaft 14 and the links 40 are engaged with the ears 93. The
work crew may then run a pair of chains or cables over the
respective pulleys 106 of the hoist mechanism 104, connect the
chains or cables to a pipe segment 11, engage a suitable drive
system to the gear 108, and actuate the drive system to rotate the
pulleys and thereby hoist the pipe segment upwardly until the upper
end of the pipe segment extends through the lower end of the
spider.backslash.elevator 74. The spider.backslash.elevator is then
actuated, with the hydraulic cylinders 77 and guiding members 86
cooperating to forcibly drive the respective slips 84 into the
engaged positions (FIG. 5B) to positively engage the pipe segment.
The slips are preferably advanced to a sufficient extent to prevent
relative rotation between the pipe segment and the
spider.backslash.elevator, such that rotation of the
spider.backslash.elevator translates into rotation of the pipe
segment.
[0036] The top drive assembly 24 is then lowered relative to the
frame 20 by means of the top hoist 25 to drive the threaded lower
end of the pipe segment 11 into contact with the threaded upper end
of the pipe string 34 (FIG. 1). As shown in FIG. 1, the pipe string
is securely held in place by means of the flush-mounted spider 36
or any other suitable structure for securing the string in place,
as is well known to those skilled in the art. Once the threads are
properly mated, the top drive motor 26 is then actuated to rotate
the top drive output shaft, which in turn rotates the lower drive
shaft of the pipe running tool 10 and the spider.backslash.elevator
74, which causes the coupled pipe segment to rotate and thereby be
threadedly engaged to the pipe string.
[0037] In one embodiment, the pipe segment 11 is intentionally
lowered until the lower end of the pipe segment rests on the top of
the pipe string 34. The load compensator 94 is then actuated to
drive the bushing 60 upwardly relative to the lower drive shaft 14
via the splined interface between the two. The upward movement of
the bushing causes the spider.backslash.elevator 74 and therefore
the coupled pipe segment 11 to be raised, thereby reducing the
weight on the threads of the pipe segment. In this manner, the load
on the threads can be controlled by actuating the load
compensator.
[0038] Once the pipe segment 11 is threadedly coupled to the pipe
string, the top drive assembly 24 is raised vertically to lift the
entire pipe string 34, which causes the flush-mounted spider 36 to
disengage the string. The top drive assembly 24 is then lowered to
advance the string downwardly into the well hole until the upper
end of the top pipe segment 11 is close to the drill floor 30, with
the entire load of the pipe string being carried by the links 40
while the torque was supplied through shafts. The flush-mounted
spider 36 is then actuated to engage the pipe string and suspend it
therefrom. The spider.backslash.elevator 74 is then controlled in
reverse to retract the slips 84 back to the respective disengaged
positions (FIG. 5A) to release the pipe string. The top drive
assembly 24 is then raised to lift the pipe running tool 10 up to a
starting position (such as that shown in FIG. 1) and the process
may be repeated with an additional pipe segment 11.
[0039] Referring to FIG. 6, there is shown a block diagram of
components included in one illustrative embodiment of the pipe
running tool 10. In this embodiment, the tool includes a
conventional load cell 110 or other suitable load-measuring device
mounted on the pipe running tool 10 in such a manner that it is in
communication with the lower drive shaft 14 to determine the load
applied to the lower end of the pipe segment 11. The load cell is
operative to generate a signal representing the load sensed, which
in one illustrative embodiment is transmitted to a processor 112.
The processor is programmed with a predetermined threshold load
value, and compares the signal from the load cell with that value.
If the load exceeds the value, the processor then controls the load
compensator 94 to draw upwardly a selected amount to relieve at
least a portion of the load on the threads of the pipe segment.
Once the load is at or below the threshold value, the processor
controls the top drive assembly 24 to rotate the pipe segment 11
and thereby threadedly engage the pipe segment to the pipe string
34. While the top drive assembly is actuated, the processor
continues to monitor the signals from the load cell to ensure that
the load on the pipe segment does not exceed the threshold
value.
[0040] Alternatively, the load on the pipe segment 11 may be
controlled manually, with the load cell 110 indicating the load on
the pipe segment via a suitable gauge or other display, with a work
person controlling the load compensator 94 and top drive assembly
24 accordingly.
[0041] Referring to FIG. 7, there is shown another preferred
embodiment of the pipe running tool 200 of the present invention.
The pipe running tool includes a hoisting mechanism 202 which is
substantially the same as the hoisting mechanism 104 described
above. A lower drive shaft 204 is provided and connects at its
lower end to a conventional mud-filling device 206 which, as is
known in the art, is used to fill a pipe segment, for example, a
casing segment, with mud during the assembly process. In one
illustrative embodiment, the mud-filling device is a device
manufactured by Davies-Lynch Inc. of Texas.
[0042] The hoisting mechanism 202 supports a pair of chains 208
which engage a slip-type single joint elevator 210 at the lower end
of the pipe running tool 200. As is known in the art, the single
joint elevator is operative to releasably engage a pipe segment 11,
with the hoisting mechanism 202 being operative to raise the single
joint elevator and pipe segment upwardly and into the
spider.backslash.elevator 74.
[0043] The tool 200 includes the links 40 which define the
cylindrical lower ends 92 which are received in generally J-shaped
cut-outs 212 formed in diametrically opposite sides of the
spider.backslash.elevator 74.
[0044] From the foregoing, it will be apparent that the pipe
running tool 10 efficiently utilizes an existing top drive assembly
to assemble a pipe string, for example, a casing or drill string,
and does not rely on cumbersome casing tongs and other conventional
devices. The pipe running tool incorporates the
spider.backslash.elevator 74, which not only carries pipe segments,
but also imparts rotation to them to threadedly engage the pipe
segments to an existing pipe string. Thus, the pipe running tool
provides a device which grips and torques the pipe segment 11, and
which also is capable of supporting the entire load of the pipe
string as it is lowered down into the well hole.
[0045] While several forms of the present invention have been
illustrated and described, it will be apparent to those of ordinary
skill in the art that various modifications and improvements can be
made without departing from the spirit and scope of the invention.
Accordingly, it is not intended that the invention be limited,
except as by the appended claims.
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