U.S. patent application number 10/299450 was filed with the patent office on 2003-04-17 for shallow depth, coiled tubing horizontal drilling system.
This patent application is currently assigned to S & S Trust. Invention is credited to Camp, David, Merecka, Jeff.
Application Number | 20030070841 10/299450 |
Document ID | / |
Family ID | 46281565 |
Filed Date | 2003-04-17 |
United States Patent
Application |
20030070841 |
Kind Code |
A1 |
Merecka, Jeff ; et
al. |
April 17, 2003 |
Shallow depth, coiled tubing horizontal drilling system
Abstract
The invention relates to a system for coiled tubing drilling of
substantially horizontal shallow depth boreholes for installation
of transmission or conveyance lines. A mobile platform mounts a
coiled tubing reel and an adjustably mounted injector head. On the
leading end of the coiled tubing is a drilling assembly, including
a drill, a drill motor, a tracking device, and an orienter. Once
the borehole has been drilled by pushing the drilling assembly
through the borehole and exiting the earth's surface, a back reamer
may be attached for enlarging the borehole as the coiled tubing is
pulled back through the borehole. Once the borehole has been
properly sized, the transmission or conveyance line may be attached
to the leading end of the coiled tubing and the transmission or
conveyance pipe pulled back through the borehole.
Inventors: |
Merecka, Jeff; (Cypress,
TX) ; Camp, David; (Cypress, TX) |
Correspondence
Address: |
Alan R. Thiele
JENKENS & GILCHRIST
3200 Fountain Place
1445 Ross Avenue
Dallas
TX
75202-2799
US
|
Assignee: |
S & S Trust
|
Family ID: |
46281565 |
Appl. No.: |
10/299450 |
Filed: |
November 19, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10299450 |
Nov 19, 2002 |
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09896025 |
Jun 29, 2001 |
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60215534 |
Jun 30, 2000 |
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60233358 |
Sep 18, 2000 |
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60258119 |
Dec 22, 2000 |
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Current U.S.
Class: |
175/19 ;
175/61 |
Current CPC
Class: |
E21B 7/04 20130101; E21B
7/068 20130101; E21B 19/22 20130101 |
Class at
Publication: |
175/19 ;
175/61 |
International
Class: |
E21B 007/26 |
Claims
What is claimed is:
1. A coiled tubing drilling and reaming apparatus for creating
substantially horizontal, shallow depth boreholes beneath the
earth's surface and for the installation of transmission or
conveyance lines, said apparatus comprising: a mobile platform; a
staging reel mounted on a first end of said mobile platform, said
staging reel constructed and arranged for storage, spooling and
unspooling of the coiled tubing; a coiled tubing injector head for
exerting both push and pull forces on the coiled tubing and for
causing the coiled tubing to penetrate the earth's surface and
moving the coiled tubing through the shallow depth borehole; means
for guiding the coiled tubing from said staging reel to the coiled
tubing injector head; means for adjustably mounting said coiled
tubing injector head at an acute angle with respect to the earth's
surface; a drilling assembly for drilling a borehole through the
earth, said drilling assembly being mounted on the end of the
coiled tubing entering the borehole; means for orienting said
drilling assembly, said means for orienting said drilling assembly
being co-located with said drilling assembly; and means for back
reaming the borehole to a diameter which allows for the pulling of
the transmission or conveyance line therethrough when pull forces
are being exerted on the coiled tubing.
2. The coiled tubing drilling and reaming apparatus as defined in
claim 1 wherein said coiled tubing injector head is mounted on a
second end of said mobile platform.
3. The coiled tubing drilling and reaming apparatus as defined in
claim 1 wherein said mobile platform is wheeled.
4. The coiled tubing drilling and reaming apparatus as defined in
claim 1 wherein said mobile platform is a self-propelled tracked
vehicle.
5. The coiled tubing drilling and reaming apparatus as defined in
claim 1 wherein said staging reel swivels on a horizontal axis.
6. The coiled tubing drilling and reaming apparatus as defined in
claim 1 wherein said staging reel traverses from one side to
another on a travel path substantially perpendicular to the long
axis of the coiled tubing.
7. The coiled tubing drilling and reaming apparatus as defined in
claim 1 wherein said staging reel is mounted to be vertically
adjustable.
8. The coiled tubing drilling and reaming apparatus as defined in
claim 1 wherein said drilling assembly includes a drill bit and a
drill motor.
9. The coiled tubing drilling and reaming apparatus as defined in
claim 8 wherein said drilling motor is a fluid motor and wherein
fluid is supplied to said fluid motor through the coiled
tubing.
10. The coiled tubing drilling and reaming apparatus as defined in
claim 8 wherein said drilling motor is an electric motor.
11. The coiled tubing drilling and reaming apparatus as defined in
claim 1 wherein the coiled tubing includes a wire line for
controlling the operation of said drilling assembly.
12. The coiled tubing drilling and reaming apparatus as defined in
claim 9 further including a gearbox.
13. The coiled tubing drilling and reaming apparatus as defined in
claim 1 wherein said means for orienting said drilling assembly
includes means for remotely changing the angular orientation of
said drilling assembly with respect to the long axis of said
borehole.
14. The coiled tubing drilling and reaming apparatus as defined in
claim 1 further including means for tracking the location of said
drilling assembly.
15. The coiled tubing drilling and reaming apparatus as defined in
claim 14 wherein said means for tracking is selected from a group
including GPS, radio signal, and sonic.
16. The coiled tubing drilling and reaming apparatus as defined in
claim 1 wherein control of the dispensing and retraction of the
coiled tubing from this staging reel is assisted by a tubing level
winder.
17. The coiled tubing drilling and reaming apparatus as defined in
claim 13 wherein said means for orienting is remotely controlled
from above the earth's surface.
18. The coiled tubing drilling and reaming apparatus as defined in
claim 17 wherein said remote control is provided by radio
signals.
19. The coiled tubing drilling and reaming apparatus as defined in
claim 17 wherein said remote control is provided by a wire
line.
20. A method for using coiled tubing to drill and backream a
substantially horizontal shallow depth borehole through the earth
for the placement of transmission or conveyance lines therein, said
method comprising the steps of: storing a length of coiled tubing
on a storage reel; unwinding the coiled tubing from said storage
reel; guiding one end of said length of coiled tubing from said
storage reel to a coiled tubing injector head; guiding the free end
of said coiled tubing through said coiled tubing injector head;
attaching an orienting tool to the free end of said coiled tubing;
attaching a tracking device to said orienting tool; attaching a
drill bit and drill motor to said orienting tool; inserting said
drill bit, drill motor, orienting tool and tracking device through
the earth's surface from above at an acute angle; causing said
drill bit, drill motor, orienting tool, tracking device, and the
coiled tubing to be pushed through the earth in a first direction
by said coiled tubing injector head and rotating said drill motor
to create a substantially horizontal shallow depth borehole;
causing said drill bit, drill motor, orienting tool, and tracking
device to pass back through the earth's surface from below; causing
an attached back reamer, said drill and drill motor, said guide
tool, and the coiled tubing to be pulled through the earth in a
second direction, opposite to said first direction, by said coiled
tubing injector head to enlarge the substantially horizontal
shallow depth borehole.
21. The method as defined in claim 20 wherein the unwinding of the
coiled tubing from said storage reel is assisted by a level
winder.
22. The method as defined in claim 20 wherein the unwinding of the
coiled tubing from said storage reel is assisted by laterally
traversing said storage reel.
23. The method as defined in claim 20 wherein said acute angle of
insertion is controlled by the angular position of said coiled
tubing injector head.
24. The method as defined in claim 20 wherein said orienting tool
is remotely controlled from a position above the earth's
surface.
25. The method as defined in claim 20 wherein said storage reel and
said coiled tubing insertion tool are mounted on separate
platforms.
26. The method as defined in claim 20 wherein said borehole is
backreamed with an enlarged bit following the pushing of the coiled
tubing in a first direction and while the coiled tubing is being
pulled in a second direction.
27. The method as defined in claim 20 wherein a transmission or
conveyance line is pulled in said second direction through the
borehole.
28. The method as defined in claim 20 wherein the coiled tubing is
left in the borehole to become a transmission or conveyance
line.
29. A system for creating a substantially horizontal shallow depth
borehole lined by a transmission or conveyance line through the
earth, said system comprising: a coiled tubing drill string having
a leading end; a reel assembly for winding, storing, and unwinding
said coiled tubing drill string; a drilling assembly mounted to the
leading end of said coiled tubing drill string, said drilling
assembly including a tracking device, a drill motor, and a drill
bit; an injector head for guiding said coiled tubing drill string
into the borehole at an acute angle to the earth's surface, for
pushing said coiled tubing through the earth and to exit the
earth's surface, for pulling said coiled tubing from the borehole,
and for lining the borehole with a transmission or conveyance line;
a connector for connecting said transmission or conveyance pipe to
the leading end of the coiled tubing drill string to enable the
transmission or conveyance pipe to be drawn into the borehole as
said coiled tubing is pulled from the borehole.
30. The system as defined in claim 29 wherein said reel and said
injector head are mounted on a mobile platform.
31. The system as defined in claim 29 wherein said mobile platform
is a wheeled trailer.
32. The system as defined in claim 29 wherein said mobile platform
is a tracked vehicle.
33. The system as defined in claim 29 wherein said drill bit is
replaced with an enlarging back reamer when said transmission or
conveyance line is pulled back through the borehole.
Description
[0001] This application claims the benefit of U.S. provisional
patent application 60/215,534, filed Jun. 30, 2000, U.S.
provisional patent application 60/233,358 filed Sep. 18, 2000; and
U.S. provisional patent application No. 60/258,119 filed Dec. 22,
2000 and is a continuation-in-part of U.S. patent application Ser.
No. 09/986,025 filed Jun. 29, 2001.
FIELD
[0002] The present invention involves horizontal directional
drilling systems; more particularly, the present invention involves
shallow depth, coiled tubing, horizontal directional drilling
systems for the installation of transmission and conveyance
lines--to include pipes, tubing, and cable.
BACKGROUND
[0003] Over the past fifteen years, methods for installing
underground transmission and conveyance lines have advanced from
digging trenches, laying lines in the trenches, and then refilling
the trenches, to using horizontal directional drilling techniques
to form subsurface boreholes and pulling pipes or tubing
therethrough. The use of horizontal directional drilling techniques
involves drilling horizontal boreholes beneath the earth's surface
using techniques similar to those perfected in the oil and gas
exploration industry for drilling deep directional or horizontal
wells in high pressure environments.
[0004] Shallow depth horizontal drilling is a method for the
trenchless installation of underground pipelines. The purpose for
the use of horizontal drilling techniques is to install shallow
depth transmission and conveyance systems in a minimal pressure or
non-pressure environment. Typically, such transmission and
conveyance lines are used with various utilities such as electrical
power, communications, natural gas, irrigation, petroleum, potable
water, storm drains, and sewer service. Shallow depth horizontal
directional drilling is accomplished by first causing the drill to
penetrate the earth's surface from above at a shallow angle, then
drilling a pilot hole beneath the earth's surface in a relatively
horizontal plane with a cutting tool or drill bit, causing the
cutting tool or drill bit to come back up through the earth's
surface, and then pulling the transmission or conveyance line; such
as pipe or tubing, back through the pilot hole once the hole has
been properly sized. Sizing is accomplished usually by the use of a
backreaming tool such as disclosed in co-pending application Ser.
No. 10/176,188, filed Jun. 20, 2002, to the same assignee.
[0005] The drilling equipment used in shallow depth horizontal
direction drilling adapts oil field technology for the purpose of
drilling horizontal boreholes through earthen materials versus
traditional substantially vertical boreholes used in deep wells.
However, unlike vertical well drilling, shallow depth horizontal
drilling is not performed under the high pressure conditions
typically found in deep wells.
[0006] The equipment generally in commercial use for shallow depth
horizontal drilling is based on the use of a rotating segmented
pipe string for drilling the borehole. Specifically, the drilling
equipment includes either a piston/chain or rack and pinion drive
mechanism which pushes or pulls a motor along a length of track.
The length of track is slightly longer than the individual segment
of drill pipe being used. During the borehole drilling process, an
individual segment of pipe is loaded onto the track. The individual
segment of pipe is then attached to the drill motor and to the
previous pipe segment by rotating the drill motor and threading
each coupling, or tool joint, together to form a long string. Once
the individual segments have been threaded and locked together, the
drill motor assembly is then thrust forward while rotating the
string of all of the pipe segments, at a slight declining angle.
The slight declining angle pushes the drill string, or series of
threadably connected individual pipe segments, forward into the
ground. Once the drill motor has reached the end of the track, the
drill string is clamped and the drill motor is counter-rotated to
enable disengagement of the drill motor from the drill string. The
drill motor is then retracted (pulled back) and another segment of
pipe is loaded on the track. This process is continued--pipe
segment by pipe segment--throughout the entire length of the
horizontal borehole that is to be produced.
[0007] During the boring or drilling process, the drill motor
continually rotates. Accordingly, the entire drill string,
including all of the connected individual pipe segments, is
rotated. The drill motor is stopped only during times when it is
necessary to change the direction of the drillstring through the
ground, and add or remove individual drill pipe segments.
[0008] The actual downhole bend or turn of all of the individual
drill pipe segments in the drill string, is typically accomplished
using a bent housing assembly. The bent housing assembly enables
the operator to push the drill string to follow the angle of the
bent housing assembly. Once the turn of the drill string is
completed, the operator engages the drill motor and the drill
string is pushed forward while the drill motor continues to spin
the entire drill string.
[0009] Once the initial borehole, or "pilot hole," has been
completed, the borehole is typically back reamed. In back reaming,
the drilling process is effectively reversed by attaching a larger
bit to the drill string, spinning the entire drill string, and
reaming a larger hole while pulling the drill string back towards
the drilling equipment, one individual pipe segment at a time.
[0010] Once the borehole has been back reamed, the drill string is
reinserted into the borehole, individual pipe segment by individual
pipe segment, and run out to the far end of the borehole. The
pipeline to be installed is attached at the exit hole and then
pulled back into the borehole by the drilling equipment. As with
pushing the drill string into the hole, when pulling the drill
string back through the borehole, each individual segment of pipe
in the drill string is pulled back--one-by-one--through the
borehole, and then detached from the next segment by the drill
motor, and subsequently put aside for future use. The drill motor
then locks onto the next segment of pipe and pulls that portion of
the drill string remaining in the borehole back through the
borehole. This segment-by-segment process continues until the new
pipe is fully placed into the ground. All of this work is done
without trenching.
[0011] The shallow depth horizontal directional drilling practices
described above are parallel to the drilling methods performed in
the oil and gas industry. However, today many drilling contractors
in the oil and gas industry are utilizing coiled tubing as a more
efficient and diversified means of drilling vertical boreholes for
the production of hydrocarbons from deep wells.
[0012] The technology of coiled tubing well drilling has been used
for approximately 30 years. During the past 7-10 years there has
been a dramatic increase in the use and applications of coiled
tubing in the oil and gas industry for use in deep wells. In coiled
tubing well drilling, a continuous line of flexible pipe is used.
The coiled tubing tube is stored on a reel. The primary advantage
of using coiled tubing for deep well drilling is the efficiency
that is gained from the absence of individual segmented pipe joints
that must be threadably connected, disconnected, and re-connected
one from another. In such applications, the leading end of the
coiled tubing never exits the earth's surface.
[0013] Historically, individual segments of drill pipe were used
for drilling and conducting operations inside an oil or gas well,
usually several hundreds or thousands of feet under the earth's
surface. Each individual segment of pipe was required to be first
positioned and then attached to the previous pipe segment and then
lowered or drilled into the ground. This drilling process, although
still frequently utilized, is at times laborious and time
consuming. With the advent of coiled tubing drilling techniques,
drilling contractors were able to supply more efficient and
reliable methods of performing many downhole operations in deep
wells. With the use of injector heads designed specifically for
guiding coiled tubing into a substantially vertical borehole, and
various other technologies, operators gained the capacity to
continuously feed equipment and fluids into both existing wells and
newly drilled wells. When working in deep wells under the pressures
encountered in deep wells, the coiled tubing must be able to not
only withstand tensile and flexural stresses associated with the
drilling process; but also must be able to withstand the internal
and external pressures experienced downhole in deep wells.
[0014] Many of the same drilling techniques that are utilized when
drilling with individual pipe segments are also carried out with
coiled tubing, but there are clear differences. In a typical coiled
tubing well drilling application, the injector head is mounted or
suspended in a vertical position above the existing well to be
worked over or drilled. The coiled tubing is then guided off a
storage reel and over a gooseneck. This gooseneck is utilized to
position the coiled tubing for direct insertion into the injector
head. The injector head controls the insertion and removal of the
coiled tubing from the well. One example of a tubing injector head
is described in U.S. Pat. No. 5,188,174 to the same assignee. A
gooseneck is necessary to provide a means for maximizing the
bending radius that the tubing must endure when making the
transition from being substantially parallel to the ground, as it
leaves the reel, to becoming perpendicular to the ground as it is
"stabbed" into the injector head and injected substantially
vertically down into the well. The coiled tubing drill string is
injected or pushed some specific depth into an oil or gas well and
the work-over or well drilling operation is performed. Once the
drilling of the well is complete, the coiled tubing is retracted,
pulled out of the well, and accumulated back onto the storage
reel.
[0015] Experience in drilling oil and gas wells has shown that
steel or metallic coiled tubing typically has a shorter life cycle
than straight segmented pipe. This shorter life cycle is due to the
bending that steel or metallic coiled tubing must endure as it is
reeled on and off the reel and run over the gooseneck. The more
bends the coiled tubing is put through, the more fatigued and
brittle the steel or metallic coiled tubing becomes, and in turn
the number of production cycles available to the user is reduced.
If a non-metallic coiled tubing is used, such as tubing made from a
high strength polymer, fiberglass, or composite materials, the
problems associated with fatigue and brittleness from multiple
bending are substantially reduced.
[0016] Coiled tubing had been predominantly utilized to clean out
existing oil and gas wells. However, with advancements in new
drilling technologies, the use of coiled tubing has been expanded
to well operations such as re-entry and horizontal deviations
(kick-offs). Recently, coiled tubing utilization has been expanded
into shallow vertical gas well drilling operations by the use of
downhole drilling motors. Modem coiled tubing drilling operations
are used to drill substantially vertical slim hole wells (wells of
smaller than normal diameter), deploy reeled completions, log high
angle boreholes, and deploy treatment fluids downhole. The use of
coiled tubing in deep directional wells or even in deep horizontal
wells (i.e., wells that begin as vertical and then deviate to
horizontal) continues to increase at a rapid rate.
[0017] The need remains, however, to adapt the coiled tubing
drilling techniques used in the drilling of deep oil and gas wells
to shallow depth horizontal drilling for the installation of
transmission and conveyance lines.
SUMMARY
[0018] The present invention includes a system, a method, and an
apparatus for utilizing coiled tubing drilling techniques to bore
shallow depth, substantially horizontal, boreholes for the
installation of transmission and conveyance lines.
[0019] The disclosed system, method, and apparatus includes a
staging reel from which the coiled tubing is wound and unwound.
After exiting the staging reel, the coiled tubing enters a tubing
guide system which guides the tubing between the storage reel and
the injector head and minimizes the bend radius of unsupported
tubing. Controlling the insertion of the coiled tubing in the
ground is a coiled tubing injector head. The coiled tubing injector
head is adjustably mounted to guide the coiled tubing through the
earth's surface from above at an acute angle and push the tubing
through the hole. The result is a shallow depth borehole
substantially parallel to the earth's surface.
[0020] Attached to the leading end of the coiled tubing is a
drilling assembly. Conventional techniques are used to locate and
guide the coiled tubing and the drilling assembly as they pass
substantially horizontally through the earth at shallow depths
beneath the earth's surface. When the initially drilled borehole,
sometimes called the pilot hole, reaches the desired length, the
leading end of the drilling assembly passes back up through the
earth's surface. The completed pilot hole may then be back reamed
to enlarge its diameter. Transmission and conveyance lines may be
attached to the back reamer to follow the back reamer through the
pilot hole. Alternatively, the transmission and conveyance lines
may be installed in the borehole after the back reaming operation
has been completed. Alternatively, the coiled tubing used in the
drilling operation may be left in the earth to act as a
transmission or conveyance line.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0021] A better understanding of the system, method, and apparatus
of the present invention may be had by reference to the drawing
figures, wherein:
[0022] FIG. 1 is a side elevational view of the horizontal
directional drilling system of the present invention mounted on a
towed wheeled trailer;
[0023] FIG. 2 is a side elevational view of the horizontal
directional drilling system mounted on a self propelled tracked
platform;
[0024] FIG. 3 is a schematic diagram of the components of a
drilling assembly with a rotating bit used for forming a pilot
hole;
[0025] FIG. 4 is a schematic diagram of the components of a
drilling assembly used for back reaming or enlarging a pilot
hole;
[0026] FIG. 5 is a schematic diagram of the components of a
drilling assembly including a deflection bit;
[0027] FIG. 6 is a schematic drawing of the components of a
drilling assembly including an impact hammer; and
[0028] FIG. 7 is a schematic diagram of the components of a
drilling assembly including a jetting tool.
DESCRIPTION OF THE EMBODIMENTS
[0029] As shown in FIG. 1 and FIG. 2 in the preferred embodiment
10, the leading end 102 of the coiled tubing 100, or the end which
enters the borehole is fitted with the necessary connectors to
enable the attachment of a variety of different tools and fittings,
generically referred to as downhole tools. Such connectors and
downhole tools are well known to those of ordinary skill in the
art.
[0030] The downhole tools used with the coiled tubing include, but
are not limited to, tracking sensors (sometimes called steering
tools, tracking devices, or tracking tools), orienters (for
mechanically changing the direction of the tool), drilling motors,
and drill bits. The combination of these downhole tools with a
drill bit at the leading end 102 of the coiled tubing 100 becomes
the drilling assembly 18 which bores through the earthen
environment encountered at the leading end 102 of the coiled tubing
100.
[0031] In the preferred embodiment 10, the drilling assembly 18
shown in FIG. 3 includes a drill motor 20. If the drill motor is an
electric motor, power to the electric motor 20 is transmitted by
wires placed within the internal diameter of the coiled tubing 100.
The electric motor 20 is selected to have sufficient power to
supply the necessary torque for drilling, or the drilling assembly
may include a gearbox, speed reducer, or torque converter 22 for
the purpose of amplifying the torque supplied by the motor 20 when
hard soils or rocky conditions are encountered Those of ordinary
skill in the art will understand that the drill motor 20 and
gearbox 22 may be combined. Alternatively, fluid motors driven by
pressurized gas or liquid may be used to provide the necessary
rotational torque for drilling. Such fluid motors shall include
those driven by compressed air or mud motors which are caused to
turn by the flow of drilling mud.
[0032] An alternate embodiment of a drilling assembly 118 is shown
in FIG. 5. At the distal end of the assembly is a push steer tool
128. Such push steer tools 128 are well known to those of ordinary
skill in the art. Following the push steer tool is a tracking
device. Mechanically connected between the tracking device and the
push steer tool 128 is the motor 120 which provides rotational
torque to the push steer tool 128 when forming a relatively
straight borehole.
[0033] When drilling mud is used, for example, with the drilling
assembly shown in FIG. 3, the drilling mud is either pumped through
the drill motor or around the drill motor 20, depending on the type
of drill motor used. The drilling mud is then projected through the
drill bit 28 for the purpose of cooling the drill bit 28 and
washing away cutting debris from the cutting faces on the drill
bit.
[0034] As the coiled tubing 100 is caused to penetrate the earth's
surface E from above and progresses forward along the desired
horizontal path, the drilling assembly cuts a borehole through the
earthen environment surrounding the drilling assembly. At some
point during the drilling operation, it will become necessary to
orient the drilling assembly to address the need to assure that the
path of the borehole follows along a desired route substantially
parallel to the earth's surface. Following a desired route is
particularly critical when the transmission or conveyance lines are
installed for utilities, as utility easements are sometimes quite
narrow and tightly defined.
[0035] As shown in FIG. 3, adjustment of the path traveled by the
drilling assembly 18 may be accomplished by the use of an orienter
30 located at the leading end 102 of the coiled tubing 100. When
the orienter 30 is used with a drilling motor with a bent housing,
the orienter is used to determine the clock position of the bend in
the drilling motor housing or its position with respect to a
360.degree. circle. When it is desired to change hole direction,
the orienter rotates the bent housing of the drilling motor. For
example, if it is desired to change the direction of the hole to
move back toward the earth's surface, the orienter 30 turns the
bent drilling motor housing to the 12 o'clock position..
[0036] An alternate type of navigational tool or orienter 30 may
provide orientation in all three spatial directions. Specifically,
the orienter 30 may provide horizontal inclination or pitch (i.e.,
up and down based on a horizontal plane), horizontal deviation or
yaw, (i.e., left and right), and clock face orientation or roll. In
this matter the orienter 30 acts like a wrist. Such orienters 30
are typically used with drilling motors having a straight
housing.
[0037] In yet another implementation of the present invention, the
orienter and tracking sensor may be combined into a single unit
attached to the drill motor.
[0038] Orientation of the drilling assembly 118 shown in FIG. 5 is
accomplished by stopping the rotation of the push tool 128 at a
desired angular orientation, then using the injector head 16 to
push the drilling assembly 118 forward. This pushing force on the
tubing will cause the tip of the push tool 128 to dig into the
earthen environment and thereby change the direction of the travel
path of the drilling assembly 118. Once the direction of the
drilling assembly has been changed, the motor 120 is caused to
rotate again and formation of the borehole will begin along a
relatively straight path.
[0039] The tracking of the underground position of the drilling
assembly 18, 118 is accomplished using well known techniques,
including either beacon communication signals, such as GPS, RF, or
sonic signals. These signals are sent from a tracking sensor 24 to
a receiver at the surface, or the signals may be transmitted via a
wire line placed within the coiled tubing 100. In the preferred
embodiment, the use of a wire line through the coiled tubing 100 is
preferred because of the better location accuracy provided.
[0040] During the entire drilling process, there is never the need
to stop the drilling operation to add multiple sections of tubing.
Once the continuous length of coiled tubing 100 is inserted into
the earth, a continuously operational drilling process occurs. This
continuously operational drilling process follows a predetermined
underground shallow depth path until the bored hole is complete.
Near the predetermined end of the bored hole, the orientation of
the drilling assembly 18, 118 is caused to project upwardly toward
the earth's surface, which causes the end of the drilling assembly
18, 118 to penetrate the earth's surface from below to complete the
pilot hole. Upon the exiting of the drilling assembly 18, 118
through the earth's surface, the drilled pilot hole becomes
complete. The drilled pilot hole may then be enlarged as described
below, lined with a conveyance or transmission line, or both.
[0041] Alternatively, the drilling operation may be done from an
entry pit to an exit pit. In this alternate method of drilling a
pilot hole, a portion of the drilling system 10, such as the
injector head 16 which has been removed from the vehicles shown in
either FIG. 1 or FIG. 2, is placed in a pre-dug entry pit. The
tubing injector head 16 then directs the coiled tubing 100 into the
soil wall on the side of the entry pit. At the distal end of the
desired underground travel path for the coiled tubing 100, a
pre-dug exit pit may be used. When the hole is complete, the
drilling assembly at the leading end of the coiled tubing 100
breaks through the wall at the side of the exit pit.
[0042] Once the drilling of the pilot hole is complete and the
leading end 102 of the coiled tubing 100, with downhole tools
attached, has come back up through the earth's surface E, the
process of back reaming the pilot hole may begin if the need exists
to enlarge the diameter of the pilot hole.
[0043] At the beginning of the back reaming operation, the operator
may remove the orienter 30 and the tracking device 24. As shown in
FIG. 4, an oversized bit, typically called a back reamer 32, is
then attached to the drill motor 20, 120. Back reamers 32 are
oversized drill bits with a cutting face directed toward the
drilling unit so that the back reamer may enlarge the pilot hole
while being pulled back through the borehole by the coiled tubing
100 already in the pilot hole. If desired, the back reamer 32 may
include an internal mechanism such as a gearbox to amplify the
output torque of the drill motor.
[0044] Once a back reamer is attached to the end of the coiled
tubing drill string, the coiled tubing drill string 100 is then
pulled back through the hole using the injector head 16. The
injector head 16 still remains located at the point of entry of the
coiled tubing drill string 100 into the ground. Providing power to
the drill motor at the leading end of the coiled tubing 100 enables
the back reamer 32 to begin rotation. As the back reamer 32 creates
a larger hole as it passes through the pilot hole, drilling mud may
still be pumped through the pilot hole. Drilling mud is supplied
through the coiled tubing 100 to clean out the enlarged
borehole.
[0045] If necessary, the pilot hole may be enlarged in steps.
Enlarging the pilot hole in steps is accomplished by pulling the
back reamer 32 into the entry pit and then pushing the tubing 100
back through the borehole to the exit pit where the next size
larger reamer is attached to the end 102 of the tubing 100. A
further advancement of the disclosed mechanized back reamer is that
one back reamer may be capable of expanding the size of the pilot
hole to multiple hole diameters. The back reamer 32 unit is either
adjustable or modular, depending on its type and design. Once the
final diameter back reamer is attached, a further coupling 34 may
be attached. This last coupling 34 is utilized to attach the
transmission or conveyance line that is to be installed. The
transmission or conveyance line is pulled behind the back reamer 32
with the pulling energy being supplied by the injector head 16
itself at the entrance to the borehole. The transmission or
conveyance line can be made from various types of material,
including but not limited to PVC, HDPE, steel, and fiberglass.
[0046] When the borehole is complete, the coiled tubing 100 and
drilling assembly 18 are removed from the borehole. The coiled
tubing 100 is wound back on the reel storage assembly 12. Once the
drilling motor 20, 120 and back reamer 32 reach the entry pit or
the entry point into the earth's surface, the transmission or
conveyance line is disconnected from the coupling 34 and the back
reamer assembly 32. The transmission or conveyance line may be left
in the ground for the purpose designated by the customer;
typically, a transmission or conveyance pipe used for a utility
service.
[0047] The drilling assembly 18 and any other downhole tools
mounted on the leading end of the coiled tubing 100 are then
removed and prepared for use at the next borehole. Typically, the
coiled tubing 100 will stay inserted in the injector head 16 as an
effective means of transport of all the equipment and relocation of
the present invention to the next jobsite.
[0048] In some applications, drilling operators may prefer to use
conventional mud motor technology, which is typically found in the
oil and gas industry and common horizontal drilling operations.
When mud motors are used, the manner in which orientation may be
accomplished, for example, as described by U.S. Pat. No. 5,485,889,
is well known to those of ordinary skill in the art. The back
reaming process can be carried out using the mud motor or by
attaching an electric motor 20 if desired to be used in conjunction
with a mechanized back reamer 32.
[0049] Another possible variation of the present invention is the
use of percussion hammers 228 as shown in FIG. 6. Such percussion
hammers 228 are driven by a fluid power motor 220 which uses either
drilling mud or compressed air. The percussion hammer 228 may be
removed if desired to facilitate back reaming.
[0050] Still another possible variation of the present invention is
the use of a jetting tool 328 of the leading end 102 of the coiled
tubing 100. Jetting tools 328, which utilize high pressure water
streams 330 to cut through earthen materials, are often more
effective in softer soils than conventional drill bits. Jetting
tools may be used for either boring the pilot hole or back
reaming.
[0051] As shown in FIG. 1, the unit may be mounted on a towed
wheeled trailer system 40; or as shown in FIG. 2, the unit may be
mounted on a self-propelled tracked platform 50. While the
embodiments shown in FIG. 1 and FIG. 2 include an operator cab 26,
those of ordinary skill in the art will understand that an
umbilical cord attached to operator controls may be used where
there is a need to distance the operator from the drilling system
10. The key features, as disclosed in both FIG. 1 and in FIG. 2,
are described below:
[0052] 1. A staging reel assembly 12 which is used for spooling and
unspooling the coiled tubing 100. The staging reel assembly 12 may
be mounted to swivel on a horizontal axis or may be adjustably
mounted 19 to be vertically raised and lowered as needed.
Alternatively, on larger units the staging reel assembly 12
traverses laterally substantially perpendicular to the long axis of
the coiled tubing to minimize tubing bends. On smaller units, a
tubing level winder 36 may be used with the staging reel
assembly.
[0053] 2. A drive mechanism which is used to project the tubing 100
forward and eventually pulls it backward. The drive mechanism is
commonly referred to as a tubing injector head 16.
[0054] 3. A tubing level winder 36 which is used for the purpose of
assisting the operation during which the coiled tubing 100 is wound
or unwound from the staging reel 12. The tubing level winder 36 may
be either part of the staging reel assembly 12 or mounted
separately on the transport vehicle 40, 50.
[0055] 4. An injector head 16 which may be supported by an
adjustable mounting to allow positioning of the injector head 16 at
an acute angle with respect to the earth's surface and moved closer
to the entry point of the leading end of the coiled tubing 100 into
the earth's surface.
[0056] 5. A guide 14 which conveys the tubing 100 from the staging
reel assembly 12 and inserts the leading end of the coiled tubing
centrally into the injector head 16.
[0057] 6. A triplex pump which is utilized for pumping drilling
muds through the tubing.
[0058] 7. An engine which provides the necessary power to operate
the complete unit.
[0059] 8. An operator station or driller's console or cab 26 which
allows the operator to perform all necessary functions required to
accomplish the drilling operation.
[0060] 9. Support devices which stabilize the equipment and, if
necessary, are used to make angle adjustments. This equipment is
also referred to as an outrigger 42.
[0061] In operation, the system of the present invention 100 is
transported to the jobsite or the entry point for the shallow depth
horizontal borehole. The trailer 40 shown in FIG. 1 is towed to the
jobsite and positioned near the entry point for the borehole. The
tracked vehicle 50 shown in FIG. 2 may be transported on a flat bed
trailer to the jobsite, then moved into position near the entry
point for the borehole. If the unit shown in FIG. 1 is used, then
the unit may either be operated from the wheeled trailer 40 or
individual components may be skid mounted to assist in removal and
placement.
[0062] Once the system of the present invention is off-loaded, it
is positioned to target a desired drilling path. The outriggers 42
on the system may be positioned and extended to stabilize the
system. The injector head 16, which is mounted on an adjustable
support at an acute angle, is then placed into position at the
desired drilling angle and as close to the ground as possible. The
drilling angle is typically not less than 10.degree. or no greater
than 45.degree. from horizontal. The operator's console 26 on
either the wheeled platform 40 or the self-propelled tracked
platform 50 may be adjusted to provide the operator with the
greatest amount of visibility to perform all necessary drilling
operations.
[0063] Typically, the coiled tubing 100 is guided into and inserted
into the injector head 16 before arrival at the jobsite. But if the
coiled tubing 100 is not inserted into the injector head 16, a
stabbing operation is required. Once the coiled tubing 100 is
inside the injector head 16 and has begun to exit at the opposite
end of the injector head 16, the necessary downhole tools are
attached to the leading end of the coiled tubing 100. As previously
indicated, a variety of tools may be attached to the leading end of
the coiled tubing 100.
[0064] Once all downhole tools required for the specific drilling
operation are attached to the leading end 102 of the coiled tubing
drill string 100, the drilling operation is started. The operator
begins the drilling operation by activating the downhole motor. The
activation of the downhole motor in turn rotates the drill bit at
the end of the drilling assembly. The coiled tubing 100 itself does
not rotate. Once the downhole motor has been engaged, the injector
head 16 begins driving the leading end 102 of the coiled tubing 100
forward. The angle at which the coiled tubing 100 enters the ground
is chosen so that the drilling assembly and the coiled tubing 100
are allowed to move along a shallow depth, horizontal path as soon
as practicable. In the preferred embodiment, it has been shown that
the horizontal path ranges from, but is not limited to, 6 feet to
50 feet depending on the jobsite. As the coiled tubing drill string
100 is pushed into the ground by the injector head 16, the drilling
assembly continuously causes a pilot hole to be to cut into the
earth. The cuttings formed as a result of the drilling operation
may be returned to the proximal end of the pilot hole by use of the
drilling fluid. During the drilling operation, the borehole is
continuously monitored by communication signals received from the
tracking sensor 24. These communication signals are transmitted and
received either by a wire line signal or some form of radio or
beacon signal. The operator then makes the necessary corrections in
drilling direction. This drilling operation continues along the
shallow depth, horizontal path until the desired exit point from
the borehole is reached. At this point the operator then positions
the drilling assembly in such a manner so that the end of the
drilling assembly and the other downhole tools move upward toward
the earth's surface and actually penetrate the earth's surface from
below. This completes the drilling of the pilot hole.
[0065] Once the pilot hole has been completely drilled, the
downhole tools are removed. Typically, all that is left on the
leading end of the coiled tubing 100 is the drilling motor. The
orienter 30 is not generally needed, and the tracking device 24 is
also generally not needed unless it is necessary to track the back
reaming operation. At this point, a back reaming bit 32 is then
attached to the downhole motor. This back reamer bit 32 is
typically oversized and designed to enlarge the hole during the
pullback operation to expand the hole to a diameter which will
allow the installation of whatever size or type of transmission or
conveyance line is desired. In some cases it may be necessary to
enlarge the borehole in multiple stages. In this scenario, one back
reaming operation occurs and then the back reamer 32 is conveyed
back through the enlarged hole and the next size back reamer is
placed on the end of the coiled tubing drill string. Once the final
size back reamer has been applied to the leading edge of the tubing
for enlarging the hole, the tubing product is typically attached
behind the back reamer through the use of a coupling 34. The
operator then engages the injector head 16 to pull the coiled
tubing 100 back through the pilot hole and activates the downhole
motor so as rotate the back reamer 32. The back reamer 32 begins to
cut the hole to the desired diameter, and the pipe to be installed
is pulled behind the back reamer 32. The combination of the coiled
tubing 100 with the equipment attached to the end 102 of the coiled
tubing (downhole motor, reamer, coupling, transmission or
conveyance line) is then pulled back through the borehole. If
desired, the coiled tubing 100 used to push the drilling assembly
through the borehole may become the transmission or conveyance line
by removing the drilling assembly from the leading end of the
coiled tubing 100 and leaving the coiled tubing 100 in the
borehole.
[0066] When the drilling is complete, all downhole tools are
removed from the coiled tubing 100 and set aside. The coiled tubing
100 itself is then checked for integrity and prepared for final
connections. This completes the description of the drilling of the
bore hole and the installation of the transmission or conveyance
line.
[0067] In an alternative application, the apparatus, method, and
system of the present invention may be used for enlarging existing
underground transmission or conveyance lines where it is possible
to place an enlarger or pipe bursting tool on the leading end of
the coiled tubing once the coiled tubing has passed through the
existing transmission or conveyance line. Specifically, the coiled
tubing is pushed through an existing transmission or conveyance
line by the tubing injector head. Once the leading end of the
coiled tubing exits the existing transmission or conveyance line
and becomes accessible, a pipe bursting tool, a reaming tool, or
other similar tools known by those of ordinary skill in the art may
be attached to the leading end of the coiled tubing and pulled back
through the existing transmission or conveyance line. If desired, a
new transmission or conveyance line may be pulled behind the pipe
bursting or back reaming tool. Or, the existing transmission or
conveyance line may be removed before a new transmission or
conveyance line is installed.
[0068] In yet still another alternative application, the system,
method and apparatus of the present invention may be used to
temporarily place cables at a shallow depth, under an object to be
lifted from the earth's surface. In such applications, a pilot hole
is first drilled under the object to be lifted and the lifting
cable is then drawn back through the pilot hole.
[0069] While the system, apparatus, and method have been described
according to the preferred and alternate embodiments, those of
ordinary skill in the art will understand that numerous other
embodiments of the disclosed invention may be made. Such other
embodiments shall be included within the scope and meaning of the
appended claims.
* * * * *