U.S. patent application number 15/297609 was filed with the patent office on 2017-04-20 for system to improve the control of downhole tool-strings used in radial drilling.
The applicant listed for this patent is Robert L. Morse, James M. Savage. Invention is credited to Robert L. Morse, James M. Savage.
Application Number | 20170107771 15/297609 |
Document ID | / |
Family ID | 58523632 |
Filed Date | 2017-04-20 |
United States Patent
Application |
20170107771 |
Kind Code |
A1 |
Morse; Robert L. ; et
al. |
April 20, 2017 |
System to Improve the Control of Downhole Tool-Strings Used in
Radial Drilling
Abstract
An apparatus, method and system for dampening the force exerted
on a tool-string when a lower portion of said tool-string is in a
subterranean lateral borehole radiating outward at least 5 feet at
an angle between 45 to about 90 degrees from a primary
wellbore.
Inventors: |
Morse; Robert L.; (Lake
Charles, LA) ; Savage; James M.; (Ragley,
LA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Morse; Robert L.
Savage; James M. |
Lake Charles
Ragley |
LA
LA |
US
US |
|
|
Family ID: |
58523632 |
Appl. No.: |
15/297609 |
Filed: |
October 19, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62285095 |
Oct 19, 2015 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 17/07 20130101;
E21B 44/02 20130101; E21B 17/20 20130101; E21B 7/061 20130101 |
International
Class: |
E21B 17/07 20060101
E21B017/07; E21B 7/06 20060101 E21B007/06; E21B 21/08 20060101
E21B021/08; E21B 3/00 20060101 E21B003/00; E21B 47/00 20060101
E21B047/00 |
Claims
1. An apparatus for dampening the force exerted on a tool-string
when a lower portion of said tool-string is in a subterranean
lateral borehole radiating outward at least 5 feet at an angle
between 45 to about 90 degrees from a primary wellbore, said
dampening apparatus comprising: a housing; a push-rod; and at least
one dampening member selected from the group consisting of: a
tension spring, a compression spring, a gas-filled chamber, an
elastomeric material, and a magnet.
2. The apparatus of claim 1, further comprising one or more of the
elements selected from the group consisting of: a spring that
extends when additional weight on bit is applied at a cutting head;
a spring that compresses when additional weight on bit is applied
at a cutting head; magnets oriented such that they repel each
other; and a sealed gas-charged chamber.
3. The apparatus of claim 1, further comprising an internal hose
running the length of the apparatus, one or more inner passageways
running the length of the apparatus, and a conduit running the
length of the apparatus external to the housing.
4. The apparatus of claim 1, further comprising one or more
anti-torque projections extending from the housing.
5. The apparatus of claim 4, wherein the anti-torque projections
provide continuous, low-drag movement when in contact with an
external member.
6. The apparatus of claim 5, wherein the anti-torque projections in
contact with an external member resists applied torque.
7. The apparatus of claim 1, further comprising a weight-on-bit
measurement device.
8. The apparatus of claim 7, further comprising a weight-on-bit
measurement transmission device.
9. The apparatus of claim 8, wherein the weight-on-bit measurement
transmission device is selected from the group consisting of:
changes in the pressure of a drilling-fluid stream, changes in the
flow of a drilling-fluid stream, an electrical transmission
line.
10. A method of dampening the force applied on a tool-string when a
lower portion of that tool-string is in a subterranean lateral
borehole radiating outward at least 5 feet at an angle between 45
to about 90 degrees from a primary wellbore, the method comprising:
providing a dampening apparatus comprising a housing, a push-rod,
and at least one dampening member; engaging the dampening member;
wherein the engaged dampening member results in at least one of the
group consisting of: the extension of a tension spring positioned
in the dampening apparatus; the compression of a spring positioned
in the dampening apparatus; the compression of a gas-filled chamber
positioned in the dampening apparatus; the compression of an
elastomeric material positioned in the dampening apparatus;
overcoming the repulsion of two like-poled magnets positioned in
the dampening apparatus; and combinations thereof.
11. An apparatus for measuring the force exerted on a tool-string
when a lower portion of said tool-string is in a subterranean
lateral borehole radiating outward at least 5 feet at an angle
between 45 to about 90 degrees from a primary wellbore, said
measuring apparatus comprising: one or more ports that are
successively opened or closed based on changes in the applied force
and thereby causing a change in the pressure of a fluid within the
tool-string that can be measured.
12. An apparatus for measuring the force exerted on a tool-string
when a lower portion of said tool-string is in a subterranean
lateral borehole radiating outward at least 5 feet at an angle
between 45 to about 90 degrees from a primary wellbore, said
measuring apparatus comprising: a pressure transducer in the
tool-string that reports either the pressure in a gas or
fluid-filled chamber or the pressure applied by a spring in the
apparatus.
13. A method for measuring the force exerted on a tool-string when
a lower portion of said tool-string is in a subterranean lateral
borehole radiating outward at least 5 feet at an angle between 45
to about 90 degrees from a primary wellbore, said method
comprising: making a first pressure measurement made by a pressure
measurement device selected from the group consisting of: changes
in drilling fluid pressure due to opening and closing of ports that
vent said fluid, a pressure transducer that measures pressure in a
gas or fluid-filled chamber, and a pressure transducer that
measures the force applied by a downhole spring; and transmitting
the first pressure measurement.
14. The method of claim 13, further comprising transmitting the
first pressure measurement through changes in pressure of a fluid
within the tool-string.
15. The method of claim 13, further comprising transmitting the
first pressure measurement through an e-line.
16. An apparatus for the transmission of torque in a drill-string
used to form an extended subterranean lateral borehole radiating
outward at least 5 feet at an angle between 45 to about 90 degrees
from a primary wellbore, said apparatus remaining in the primary
wellbore and comprising an inner spline member and an outer spline
member, the inner spline member in contact with the outer spline
member and having a low coefficient of drag between them.
17. A method for the transmission of torque in a drill-string used
to form an extended subterranean lateral borehole radiating outward
at least 5 feet at an angle between 45 to about 90 degrees from a
primary wellbore, said method comprising: providing a torque
transmission apparatus comprising an inner spline member and an
outer spline member, the inner spline member in contact with the
outer spline member and having a low coefficient of drag between
them; placing the torque transmission apparatus within the
drill-string in the primary wellbore; and connecting the torque
transmission apparatus to a tool string that extends into the
lateral borehole.
18. A system to improve the efficiency of a tool-string used to
form an extended subterranean lateral borehole radiating outward at
least 5 feet at an angle between 45 to about 90 degrees from a
primary wellbore, said system comprising: at least one projection
extending from the tool-string; and at least one slot on an
external device into which the at least one projection can engage;
wherein when the at least one projection engages with the at least
one slot that resist a counter torque exerted on the
tool-string.
19. An system to improve the efficiency of a tool-string used to
form an extended subterranean lateral borehole radiating outward at
least 5 feet at an angle between 45 to about 90 degrees from a
primary wellbore, said system comprising: a weight indicator; and a
load dampener.
20. The system of claim 19, further comprising a load-balanced
piston and a spring for additional dampening.
21. The system of claim 19, further comprising a spline mechanism
for the transmission of torque.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present filing claims priority to provisional patent
application 62/285,095 filed on Oct. 19, 2015.
FIELD
[0002] The present disclosure generally relates to drilling
wellbores into a subterranean formation and more particularly to
short radius lateral drilling procedures. This disclosure addresses
control efficiency of short radius lateral drilling procedures and
has application to oil, gas, water and geothermal wells.
BACKGROUND
[0003] Natural resources such as oil and gas located in a
subterranean formation can be recovered by drilling a wellbore down
to the subterranean formation, typically while circulating a
drilling fluid in the wellbore. The wellbore is drilled with the
use of a tool string consisting of drill pipe, various tools and
having a drill bit on the distal end. During the drilling of the
wellbore drilling fluid is typically circulated through the tool
string and the drill bit and returns up the annulus between the
tool string and the wellbore. After the wellbore is drilled
typically the tool string is pulled out of the wellbore and a
string of pipe, e.g., casing, can be run in the wellbore. The
drilling fluid is then usually circulated downwardly through the
interior of the pipe and upwardly through the annulus between the
exterior of the pipe and the walls of the wellbore, although other
methodologies are known in the art.
[0004] Slurries such as hydraulic cement compositions are commonly
employed in the drilling, completion and repair of oil and gas
wells. For example, hydraulic cement compositions are utilized in
primary cementing operations whereby strings of pipe such as casing
are cemented into wellbores. In performing primary cementing, a
hydraulic cement composition is pumped into the annular space
between the walls of a wellbore and the exterior surfaces of the
casing. The cement composition is allowed to set in the annular
space, thus forming an annular sheath of hardened substantially
impermeable cement. This cement sheath physically supports and
positions the casing relative to the walls of the wellbore and
bonds the exterior surfaces of the casing string to the walls of
the wellbore. The cement sheath prevents the unwanted migration of
fluids between zones or formations penetrated by the wellbore.
[0005] The drilling of a horizontal well typically involves the
drilling of an initial vertical well and then a lateral extending
from the vertical well which arcs as it deviates away from vertical
until it reaches a horizontal or near horizontal orientation into
the subterranean formation.
[0006] In short radius drilling specialized tools are swept around
a tight radius of a whipstock and are then used to form lateral
boreholes radiating outward and into the subterranean formation.
Short radius lateral drilling is distinct from more-familiar
conventional horizontal and coil tubing drilling. In conventional
horizontal and coil tubing drilling procedures, the drilling tools
are swept around a radius or "heel" that is hundreds or even
thousands of feet in size. That is, in both of these procedures
virtually all of the change in direction takes place outside of the
wellbore proper. By contrast, in short radius drilling, the primary
change of direction occurs inside of the wellbore itself--that is,
it occurs literally in the matter of a few inches.
[0007] As wellbores suited to this procedure commonly have a
diameter of between about 41/2'' to 7'', this equates to radii of
between about 21/4'' to about 31/2'' inches. In many short radius
lateral drilling procedures a full 90 degree arc or "heel" is
completed within the wellbore--that is, within about 0.25 ft (3
inches). This contrasts markedly with coiled tubing drilling, which
often requires on the order of 250 feet and with conventional
horizontal drilling which can utilize on the order of 2,500 feet
for a full 90 degree heel. Conventional horizontal drilling
technologies operate at a scale 3 to 4 orders of magnitude larger
than those of short radius lateral drilling technologies.
[0008] The process of "radial drilling" entails forming extended
boreholes (e.g. at least 5 feet) in earthen formations that extend
outward from a primary wellbore. In radial drilling, the exit angle
from the primary wellbore ranges from 45 degrees to slightly over
90 degrees and form a "radial borehole". As one might imagine,
radial boreholes entail extraordinarily high "build-angles" for the
tools. That is, these build-angles are diametrically opposed to
those found in conventional rig-based or coiled tubing-based
horizontal drilling procedures. In these arts, the tool-string
exits the wellbore at extremely shallow exit angles, typically no
more than 3 to 5 degrees.
[0009] In radial drilling the "heel" of the lateral sweeps out its
arc in the matter of a few inches. In fact, typically the entire
change of direction takes place inside of the wellbore itself. As
typical wellbores range from about 41/2 to 9 inches in diameter,
the heel (or radius) in radial drilling procedures is literally
inches. In more common coiled tubing drilling or conventional
horizontal drilling, the heels are 100s or 1000s of feet in size.
Basically, radial drilling procedures operate at a scale that is 3
to 4 order of magnitude less than industry-standard methods.
[0010] Radial drilling procedures typically entail the placement of
a whipstock at a target depth inside the wellbore. Sometimes the
whipstock is run on the end of upset or production tubing. Radial
drilling related tools and procedures can be used on open-hole
completed or cased hole wells. If no opening is present in a cased
well, access to the formation is sometimes gained by milling out a
section of the metal well casing. More commonly, however, a
specialized tool-string is moved down the wellbore and are used to
form a small round hole in the casing. In known practices, the
tools used to form the hole in the casing are then retracted and a
separate formation-drilling tool is inserted downhole. The
formation-drilling tools are then directed by the whipstock toward
the earthen formation or target zone (through the existing hole in
the casing). Obviously, in open-hole completed wells, there is no
need to cut the casing. Regardless of whether the well is cased or
open hole completed, the tools are manipulated by some form of
control-line. The control-line might be a wireline unit, a coil
tubing unit (CTU) or jointed-tubing.
[0011] The present disclosure generally relates to a system to
improve the control efficiency of radial drilling procedures. This
disclosure has applicability to oil, gas, water and geothermal
wells. In applications this disclosure also allows for wireline
units and large diameter coiled tubing units (CTUs) to work
efficiently with the "small-scale" tools used in procedures
involved in forming or running tools within radial boreholes.
[0012] Radial drilling tools are most often deployed by a
specialized subcategory of CTUs known as "capillary units".
Presently, the preferred method to deploy radial drilling tools is
via purpose-built capillary units. These specialized CTUs are
equipped with small-diameter coil tubing--typically 1/2'' to 3/4''
in diameter--and, are paired with smaller, more-precise
injector-heads and reels. These "smaller" units contrast with
conventional or "full-sized" CTUs in important ways. For example,
conventional-scale CTUs utilize much larger and heavier tubing,
typically in the range of 11/4'' to over 3'' in diameter.
Accordingly, the size of the surface equipment is much larger in
order to handle the stiffer and appreciably heavier coiled tubing
sting.
[0013] Further difference in the injector-heads, the surface-based
device above the wellhead that is used to reposition the
control-line, also warrants mention. It is ultimately the
injector-head that controls the motion on the control-lien and
hence weight on bit (WOB) of the downhole tool-string. Again, the
"WOB" might be the measure of actual weight on drill bit or merely
the set-down force being applied on a tool-string that extends into
a radial borehole. Smaller CTUs such as those commonly used in
radial drilling applications have injector heads commonly rated for
about 5,000 to 10,000 lbs. By contrast, large-diameter CTUs
commonly have injector heads capable of pulling over 50,000 lbs.
and sometimes can lift well over 100,000 lbs. A further difference
between conventional coiled tubing drilling and radial drilling
pertains to the range of WOB. In radial drilling, typically the
target WOB ranges from about 100 to less than 1,000 pounds. By
contrast, in coiled tubing drilling (performed with larger coiled
tubing) target WOB commonly ranges from about 5,000 to over 10,000
pounds.
[0014] In radial drilling, the smaller purpose-built CTUs are often
designed in an effort to more precisely control the up-and-down
movement of the coiled tubing string. For example, manufacturers
try to control the tubing movement in increments as small as 1/8 of
an inch. By contrast, conventional CTUs with their large
injector-heads cannot reliably reposition coil-tubing in such fine
increments, instead they often operate more on the scale of a 1
inch or so. This is not surprising given that these injector-heads
are commonly designed to move 10,000 to over 100,000 pounds at
speeds sometimes exceeding 125 feet per minute. It is hard to
combine the "brute force" necessary to handle such large weights
with a "feather-touch" desirable for radial drilling applications.
For one wanting to use a large CTU/injector-head for radial
drilling this situation presents an enormous challenge as WOB may
need to be managed to below 100 pounds.
[0015] Regardless of the control-line and surface equipment used,
another need in radial drilling pertains to maintaining a
near-constant WOB. The equipment operator needs to feed the
control-line into the well at exactly the same rate that the
cutting head optimally drills the radial borehole. If the tubing is
put in too fast, WOB can be excessive, helical buckling of the
control-line can occur and tool-string strings can be damaged. If
WOB is too low, the rate of penetration (ROP) suffers, drilling
times (and costs) are increased and excessive wear-and-tear can
occur on the downhole tools. Basically, regardless of the
control-line type, e.g. whether a large CTU or small one, there is
a need for an apparatus that aids the equipment operator in
maintaining the correct WOB during radial drilling
applications.
[0016] Radial drilling systems require specialized tools to form
the radially-oriented boreholes. Typically these purpose-built
drill-strings include some form of flexible hose or short-segmented
elements, either of which can be moved around the extremely tight
radius inside the whipstock. Because of the scales involved, the
tools used in radial drilling procedures are a far smaller in size
than those used in conventional horizontal drilling, where there is
the luxury of sweeping out the majority of the bend (the heel)
after the tool has exited the wellbore.
[0017] In most radial drilling procedures the well casing is cut
mechanically, but the lateral borehole through the formation is
produced by a jetting nozzle run on the end of a hose. Since hoses
are flexible, the obvious appeal to this approach is the ease with
which the hose transitions around the tight radius of the
whipstock. The tools described in this disclosure are different
from and not intended for use with the jetting tools used to erode
boreholes in radial drilling applications. In jetting drilling
systems, the jet head typically has back-jets used to pull the hose
forward. By contrast, the tools of this disclosure pertain to
applying a desired WOB by pushing on a mechanical tool.
[0018] Certain newer and more reliable forms of radial drilling
entail mechanically cutting the earthen formation. In some
instances, these tools are composed of short individual-elements
which transition around the tight radius of the whipstock. Yet
other radial drilling embodiments entails some form of
counter-wound spring or flexible tubular member that is also pushed
against the formation face. Problems with these new systems
include: ambiguity of applied WOB; the need to "dampen" or soften
the applied WOB (such as when using large CTUs); the need to stop
the reverse-torque transferred back up the flexible drill-string if
the control-line cannot resist this torque; and the need to
transfer or deliver torque from the motor to the flexible
tool-string being run into or used to form the radial borehole.
[0019] In current radial drilling procedures, the equipment
operator attempts to estimate the WOB by looking at their string
weight or tare weight. Typically this is done by looking at the
reported value from a load-cell positioned on the injector head. In
other instances (where an injector head is not used) weight can be
indicated by a load-cell measuring the forces acting on a
"gooseneck" or rotating sheave. If a radial drilling procedure is
being performed at a depth of say 5,300 feet, this effectively
means that the equipment operator is trying to determine the WOB
using sensors positioned more than a mile away.
[0020] While such great distances invite accuracy errors, several
other problems arise in radial drilling applications. For example
as coiled tubing is spooled into the well, it retains a
residual-bend. This residual-bend loads onto whatever the coiled
tubing first contacts, typically production tubing that is attached
to the whipstock. This side-loading has the effect of "holding-up"
or stacking-off some of the weight of the tubing. This stacking-off
translates into ambiguity in the reported WOB via the tare weight.
A further problem that affects radial-drilling procedures performed
with small "flexible" control-lines (e.g. small diameter coiled
tubing) is helical buckling. Thus, as the operator lowers the
control-line and the attached tool-string encounters an
obstruction, the control-line begins to helically-buckle, adding
yet further ambiguity to reported WOB values.
[0021] A further problem that can affect radial-drilling
applications pertains to the reverse torque caused by tool-strings
that mechanically drill the radial borehole or otherwise rotate a
lower tool-string. This issue is not a problem with large diameter
coiled tubing because of the high torsional stiffness of the
tubing. However, it is a significant factor in control-lines that
involve small diameter coiled tubing or e-lines. Basically, these
later control-lines lack the torsional stiffness to resistance the
reverse-torque transmitted up the drill-string. Given this flaw,
yet another solution is needed for efficient radial drilling
applications. For systems that utilize a jetting nozzle to form the
hole in the earthen formation this is not an issue, as no
meaningful reverse torque is created, not even by a rotating
nozzle. Another requirement is that the tool used to resist the
torque does so without adding inaccuracies in the WOB values. More
specifically, the solution needs to avoid introducing sliding
members that producing high-friction/drag that once again creates
reported WOB inaccuracies. A final feature of the solution is that
it must allow drilling fluid to pass to the lower tool-string in
order to wash cuttings out of the radial borehole and/or to exit a
cutting head.
[0022] Thus, a need exists for a practical system in short radius
lateral drilling to maintain desired WOB.
SUMMARY
[0023] This disclosure provides a method and apparatus for
efficiently forming extended radial boreholes in earthen formation
while maintaining a desired WOB. This system can be deployed by a
variety of control-lines such as a wireline unit, jointed-tubing or
coiled tubing.
[0024] This system addresses several problems that currently
trouble known radial drilling systems including: 1) it allows the
equipment operator to more accurately determine WOB; 2) it enables
cutting fluid to wash cuttings debris out of the radial borehole;
3) it dampens the applied weight downhole as the control-line is
vertically manipulated; 4) it allows one to continuously form (or
drill) the radial borehole without the need to reset or stop the
tool during the process; 5) it allows for the efficient
transmission of torque to a lower tool-string in mechanical radial
drilling applications; and 6) it offers a low-drag solution to
simultaneously counteract the reverse-torque of a mechanical
tool-string as that string drills into earthen formation.
[0025] This disclosure allows radial drilling tools to be run on
jointed-tubing, wireline units or coiled tubing of any size.
Essentially any of these deployment means can be used in
conjunction with and benefit from the system and apparatus
described herein. To address the weight control problem, which is
especially pronounced when using "clumsy" full-sized CTUs, this
disclosure employs a "dampening" sub-assembly. Thus, regardless of
the type of control-line or surface control equipment, the
equipment operator is able to slowly and smoothly feed tools into
the radial borehole.
[0026] Certain embodiments of this disclosure entail a means of
reporting to the equipment operator the force (or weight) being
applied at the tool-string so that accurate determinations of WOB
can be ascertained. This combination of more accurately reporting
WOB and dampening the applied WOB (drive thrust) allows the
operator to stay within the desired WOB/ROP "sweet spot" throughout
the process of forming the radial borehole. It also has particular
applicability when deploying radial drilling procedures out of
horizontal wells, where the force acting on the tool must be
measured since the "weight" (vertical) becomes very inaccurate.
[0027] Particularly noteworthy is the fact that this solution has
been designed for a continuous dampening of WOB during the
formation drilling step. For example, one can drill 5, 10, 50 feet
or more using this approach and, the operator does not need to
reset or otherwise stop the tools to insure the tools operations.
Moreover, this dampening functionality is integral to the
tool-string itself and does not require some form of "landing out"
on an external member.
[0028] As this disclosure is ordered to improving the operation of
tools used in connection with forming radial boreholes in the
earthen formation, provisions are made to insure that fluid (or
gas) can reach the end of the tool-string. Further, as embodiments
of the apparatus are intended to be used tools used to mechanically
drill the radials, a means for transmission of torque through
certain apparatus is provided. Embodiments of this disclosure can
be placed in a tool-string below a motor and used to transmit
torque to a lower tool-string. In certain embodiments this
disclosure also provides a means to resist torque such as might be
required when using a wireline unit or small diameter coiled tubing
that lacks the torsional stiffness necessary to counteract reverse
torque created by mechanically drilling the radial borehole. The
different embodiments of this disclosure can be placed at varying
positions in the downhole tool-string and these positions are also
noted.
BRIEF DESCRIPTION OF DRAWINGS
[0029] The accompanying views of the drawing are incorporated into
and form a part of the specification to illustrate several aspects
and examples of the present disclosure, wherein like reference
numbers refer to like parts throughout the figures of the drawing.
These figures together with the description serve to explain the
general principles of the disclosure. The figures are only for the
purpose of illustrating preferred and alternative examples of how
the various aspects of the disclosure can be made and used and are
not to be construed as limiting the disclosure to only the
illustrated and described examples. The various advantages and
features of the various aspects of the present disclosure will be
apparent from a consideration of the figures.
[0030] FIG. 1 illustrates a zoomed out view during a radial
drilling procedure wherein a downhole toolstring has exited a
whipstock and is drilling a hole in earthen formation with the
benefit of a dampener subassembly and separate weight indicator
assembly.
[0031] FIGS. 2A & 2B illustrate a no weight on bit (WOB) and
WOB condition, respectively.
[0032] FIG. 3a illustrates a dampener sub-assembly having a spring
and piston in a "no-load" or no WOB condition.
[0033] FIG. 3b illustrates the apparatus of FIG. 3A but in a WOB on
bit situation, with the spring dampening the load.
[0034] FIG. 4 illustrates a dampener sub-assembly that utilizes a
gas charge as the dampener and has a pressure transducer located in
a piston so that the amount of force can be communicated up the
control-line.
[0035] FIG. 5A illustrates a dampener sub-assembly with a
fluid-based weight indicator mechanism. The dampener sub-assembly
is in a no-load (no WOB) condition.
[0036] FIG. 5B illustrates the dampener sub-assembly of FIG. 5A in
a WOB condition, evident by the compressed spring. Furthermore,
certain ports in the push-rod can no longer vent-off, causing a
change in the fluid pressure that can be read at the surface by the
operator.
[0037] FIG. 6A illustrates an integrated sub-assembly that can
transmit torque, dampen applied forces, indicate weight and allows
for the transmission of fluid.
[0038] FIG. 6B illustrates the FIG. 6A in cross-section at line B
and shows the spline-nut.
[0039] FIG. 6C illustrates the FIG. 6A in cross-section at line C
and shows the dampener sub housing, spline-nut, spline-rod or
push-rod, and a hole at the center of the push-rod to allow flow.
As evident, torque can be transferred through the spline-rod to the
spline-nut.
[0040] FIG. 6D illustrates the FIG. 6A in cross-section at line D
and shows how this portion of the push-rod also has splines in
order to carry torque when in contact with the spline-nut of FIG.
6A.
[0041] FIG. 6E illustrates the FIG. 6A in cross-section at line E
and shows an inside hole that runs through the push-rod.
[0042] FIG. 7A illustrates an anti-torque tool situated above the
output shaft of a downhole motor. Projections on the anti-torque
tool engage an extended track in a rigid external member to prevent
rotation. A flexible drill-string and a drill-head hang below the
motor.
[0043] FIG. 7B illustrates the apparatus of FIG. 7A drilling a
lateral borehole.
[0044] FIG. 7C illustrates the apparatus of FIG. 7A in
cross-section at line B.
[0045] The projections attached to the motor engage the rigid
external member, which in this case is an extended slot made into
the production tubing.
DETAILED DESCRIPTION
[0046] The disclosure described herein has several features most of
which can be selectively employed depending upon the tools being
run downhole and the control-line and surface equipment deploying
them. The various embodiments of this systems can be used with
wireline, jointed-tubing or coiled tubing (and CTUs) of any size.
As described more fully below, this disclosure helps the equipment
operator more easily keep the downhole tools within the WOB/ROP
"sweet-spot" when those tools are in the extended radial
borehole.
[0047] The apparatus of this disclosure can involve more than one
sub-assembly and these sub-assemblies can be positioned at varying
points along the downhole tool-string. For example, an anti-torque
apparatus disclosed herein can be positioned above a downhole
motor, while the dampening system disclosed herein could be
positioned below the motor. Notably, as the parts comprising the
apparatus are generally long and of a large diameter, they do not
traverse around the radius of the whipstock, i.e. they do not
extend into the lateral borehole itself.
[0048] In most embodiments, the apparatus of this disclosure
comprises a dampening sub-assembly to allow the equipment operator
to better control WOB. In each such case, this dampening
sub-assembly is a mechanically compliant element used to slow and
soften the transference of weight as the control-line is fed into
the well and the head of the tool-string encounters resistance from
the formation face. This dampener apparatus reduces any "jerky"
motion in the control-line from being transferred to the downhole
tools. For example, if a large CTU injector-head "surges" forward
in a 1 inch increment, the dampener sub-assembly softens the force
seen at the head of the tool-string. This feature helps prevent the
tool-sting from becoming overloaded or damaged by the excessive
force. Of course, once the lower tool-string has extended a little
further into the formation, the now-compressed dampener would
extend slightly and thereby help to maintain a favorable WOB. In
instances where the downhole tool-string is being used to cutting
the radial borehole, this can allow for an optimal ROP.
[0049] The dampening sub-assembly would consist of an exterior
housing, a piston (or push-rod) and a dampening means. The upper
end of the dampener-sub would affix to the tool-string by means of
the housing on its one end and the lower end of the dampener-sub
would affix to the lower tool-string by means of the piston; these
connections can be accomplished by means of threading. In
embodiments, the dampening means within the dampener sub would be a
compression-spring or Bellville washer(s); in other embodiments the
dampening mechanism could be a tension-spring or gas-filled
chamber. In yet other embodiments, dampening could be achieved by
elastomeric material or the use of magnets that are positioned
proximally and in identical polarity so as to repel one
another.
[0050] The dampening means would be used in conjunction with and in
order to act upon the aforementioned piston or push-rod and
housing. The dampening means (e.g. a compression-spring) and the
piston could be positioned inside the aforementioned housing, with
one side of the piston extending beyond the housing. In this
fashion one can protect the dampening system from wellbore
contaminants. In embodiments involving compression-springs, the
spring would generally be positioned away from the lower tool-sting
to as sit in a space between the piston and housing so as to be
compressed when WOB was applied. One end of the spring would act
upon the piston while the other end of the spring would "push"
against the housing. In embodiments, the spring could circumscribe
the piston and yet act upon the piston by means of a nut or other
rest affixed to the piston. Like the compression-spring,
embodiments using a gas-filled chamber, elastomeric material or
opposing magnets would be generally situated toward the top of the
dampener-sub-assembly so as to compress in when WOB was applied. In
embodiments entailing a tension-spring, the location of the spring
would be reversed from that of the compression spring, namely this
spring would be nearer the lower tool-string. Moreover, usage of a
tension spring would require that it be firmly affixed to both the
housing and the piston.
[0051] As is more evident in the figures, the dampener sub-assembly
could easily be flipped end-wise. That is, the piston could extend
out of the top of dampener-sub-assembly (and then connect to the
upper tool-string), while the main housing of the dampener sub is
positioned below and connects to the lower tool-string. Similarly,
when a gas-filled chamber (or shock) was employed, the piston on
which it acts could extend upward or downward.
[0052] The dampener assembly is always position above the flexible
portion of the tool-string that moves through the whipstock. In
operation, as the control-line is moved downward and the end of the
flexible tool-string contracts the formation, the housing and
piston would act against one another via the dampening means. This
dampening means would thus moderate any spike in force applied by a
jerky lowering of the tool-string. As the lower tool-string formed
a slightly longer lateral, the dampener assembly would then
re-extend slightly to assure the continued application of WOB.
Notably, this is a continuous drilling system. That is, the
operator does not simply "land out" a portion of the tool-string
against some form of external stop in the wellbore or on the
whipstock and then let the weight "drill off". Instead the operator
continuously feeds the tool-string down the wellbore as the lower
tool-string penetrates further into the zone. The combined
functionality of dampened WOB and continuous feeding allows for
high ROPs, reduced stalling, and an increased life-span of the
sensitive tools used in radial drilling of the borehole.
[0053] Embodiments of the tool involve using a control-line that is
incapable of sufficiently counter-acting torque, such as when
deployed by wireline or small-diameter coiled tubing. To address
this problem one or more anti-torque projections or "projections"
would be incorporated into the downhole tool-string. These
projections would be integral or rigidly affixed to the tool-string
and would be positioned above the rotating, lower portion of the
tool-string. The outside of the projections would engage with a
stationary and stiff/unyielding external member such as a slot,
rail, or similar "extended slide" mechanism. With this combination
of projections and extended slides, the reverse torque could be
resisted over the full length of the lateral being drilled. In
embodiments, this stiff extended slide would be made of specially
modified upset tubing such as that to which the whipstock may be
attached.
[0054] These projections might not slide freely against the
extended slide--such as when resisting high reverse-torque loads.
Besides impacting ROP this tends to negating accurate WOB
reporting. To negate this problem, this disclosure incorporates
means for low-drag travel between the projections and extended
slot. This could be accomplished using low-friction materials or
some form of bearings or rolling member. For example, the
low-friction materials might be brass, Teflon, oil impregnated
bronze, or other known materials having a low friction
co-efficient. If drag were still too high for smooth lateral
movement of the tool-string while under torque, the anti-torque
projections could comprise a rolling means, such as cam-followers.
Moreover, the slides could be polished or ground to attain an
extremely smooth.
[0055] Certain embodiments of this disclosure provide the equipment
operator an accurate indication of the downhole WOB. This can be
done by specially modifications to the dampener-sub-assembly. In
embodiments, this is done by placing a load-cell between the end of
the springs and the housing in order to measure the applied load.
In embodiments where a gas-filled chamber is compressed a pressure
transducer can be used.
[0056] The WOB value can be sent to the surface by means of the
control-line. In the instance of wireline deployments, this can be
done directly thru a conductor cable in the wireline, while in the
instance of coiled tubing or jointed-tubing it can be done by mud
pulse telemetry. In one variant discussed below, no special
electrical componentry is required to convey this information thru
the drilling fluid to the surface.
[0057] In these embodiments, WOB is ascertained at the surface by
directly measuring pressure or flow change that occur in the
drilling fluid when a specially-modified dampening apparatus
experiences changing loads. In these embodiments when the drilling
fluid flowing through the special dampener apparatus, the fluid
passes a number of ports that would be either opened or closed
depending upon the degree of compression (or extension) of the
dampening tool. If the special dampener assembly was highly
compressed, such as when experiencing a high WOB, several of these
ports could be open. The opening of successive ports would vent
pressure/flow causing a corresponding drop in the fluid pressure
and slight increase in the drilling fluid flow rate. The pressure
loss evident through each of these pre-defined ports would be known
and would correspond to known changes in the applied weight on this
special dampener-sub (based upon the known spring). That is, with a
known spring rate and with known travel distances between the
ports, one could accurately infer WOB based on the changes in the
drilling fluid pressure. Again, these values could be measuring the
drilling fluid pressure or flow rate at the surface. With this
tool, the operator could know the WOB and thereby easily keep the
downhole tool in its ROP "sweet spot". The damping apparatus could
have sealing mechanisms (e.g. o-rings) between the piston and the
cylinder walls to negate any unwanted leakage out of the tool. This
could prevent any unwanted leakage out of the
dampener-sub-assembly. Furthermore, in embodiments one or more
other o-ring could be employed to isolate an upper and lower
chamber between the piston and dampener housing, such as would be
useful when wanting to shut off certain vent ports. In certain
embodiments, the dampener-sub incorporates a balanced-piston
mechanism. That is, one could create a situation where the
hydraulic forces acting on the piston (from above and the from
below) were acting over equal areas so as to negate any resultant
hydraulic forces imbalance that would bias the piston or rod in a
lateral direction. In this fashion only the overall compression of
the dampening-sub via WOB would move the piston.
[0058] The vent ports would be of known sizes. Under any minimal or
zero WOB scenario, all of the ports could be blocked or "closed"
because of an o-ring on the piston/push rod. In operation, the
operator would know that they either had zero or below-threshold
WOB as no ports were opened (no pressure drop was seen). However,
once the threshold WOB was attained--hence moving the spring and
piston--a first vent port would open and some pressure would bleed
off. This would tell the operator they had exceeded the
corresponding first (known) WOB value. Knowing the size of the
various holes and the resultant change in pressure/flow readings
(from prior testing), the operator could determine approximately
how much WOB was being applied at the dampener-sub.
[0059] A practical example, here, may be helpful. For example, if
every port bled off 50 psi in the drilling fluid, if the operator
saw a 200 psi drop in pressure from baseline, they could quickly
ascertain the WOB by knowing the spring rate. Let's say each port
was spaced 1 inch apart, then this 200 psi pressure drop would
equated to 4 ports being vented (at 50 psi/port) or 4 inches of
travel. If the spring rate (known) was 100 lbs/inch, then the WOB
would be 400 lbs. In this fashion, an operator could now monitor
the downhole WOB in real-time. Moreover, using such an apparatus
along with the continuous drilling methods discussed above, one can
reliable drill at the optimal ROP.
[0060] In embodiments where the dampener-sub is positioned below a
motor, it is necessary for the dampener-sub to transmit torque.
This can be accomplished by a spline. Optionally, the spline may be
incorporated into a special a dampener-sub that indicates weight or
one that does not indicate weight. In most embodiments, the spline
is integral to the dampener-sub and comprises a series of grooves
extending lengthwise along an extended portion of the push rod or
cylinder. Said in other words, the design entails the push rod of
the dampener-sub also serving as an extended spline shaft. A spline
nut rides on the spline shaft and is integral or firmly attached to
the dampener-sub housing. In this fashion, the spline shaft and
mating nut transmit torque. This arrangement allows for the
transmission of toque under compression/extension--an ideal
feature, especially in instance where the spline is integral to a
dampening-sub.
[0061] To assure fluid (or gas) through the tool-string, each of
the apparatus of this disclosure would allow flow through their
inside or around their outside. For example, this could be
accomplished by a hose running through the interior of the
respective sub-assembly or an external by-pass tube. As the
dampener assembly requires compression and extension, one could use
a coiled hose either within or along the outside of the main
dampener housing. In other embodiments, flow could be thru a hole
running the length of the piston in the dampener assembly.
Furthermore, one or more o-rings could provide a seal between the
piston or push-rod and the inside housing of the dampener
assembly.
[0062] In embodiments an extension of the spline shaft also
incorporate the ported vents used to indicate weight, as discussed
above. In these embodiments, this apparatus has accomplished the
very desirable objectives of: smoothing the application of WOB (via
the dampener), reporting the WOB to the equipment operator (via the
ports and pressure changes); and, transmitting torque (via the
spline).
[0063] Similar to the issue discussed above for assuring a
low-friction surface between the projections and extended slots,
the splines subs of this disclosure also provide for a low-drag
means experiencing high torque loads. In embodiments the "male" and
"female" members of the spline could be made of or coated with a
material whose coefficient of friction is low, could incorporate
hardened or ground and polished surfaces or could transmit the
torque through a series of recirculated balls positioned between
the spline shaft and the spline nut.
[0064] In another embodiment, the spline apparatus consists of a
series of long axial rods positioned toward the outside of the tool
and forming a sort of "cage". The rods could be held into position
by a housing. An extended, mating "star" would be positioned inside
the cage created by the axial rods. Torque could thus be
transferred through this "spline" by means of the extended axial
rods and mating star. A dampening mechanism, like those described
above could be positioned between the housing and the end of the
star so as to again moderate the applied WOB.
[0065] The present disclosure also has applicability to forming
radial boreholes out of conventional horizontal or slant wells. As
the radial drilling string sweeps out the horizontal or slant, the
reported weight of the coiled tubing and tool-string becomes
inaccurate. This occurs because the weight of the coiled tubing and
the tool-string is being supported by the horizontal or slant leg
and hence the load-cell at the surface becomes highly unreliable.
Moreover, as one pushes the control-line out the horizontal or
slant leg, the inferred WOB can become increasing inaccurate due to
helical buckling. Used on horizontal wells, the disclosure
discussed above can be used to provide operating personnel more
accurate WOB values (via the weight indicator means) and to control
WOB (via the dampener).
[0066] In the sections above we've discussed the different aspects
of this disclosure and how they address various current
short-coming in the art of radial drilling. In essence this
disclosure addresses the following four shortcomings: 1) Weight
Indication: the means of this disclosure to indicate WOB to the
operator; 2) Dampening: the means of this disclosure to smooth the
application of WOB; 3) Torque-Transmission: the means to convey
torque through a tool-string with this disclosure; 4) Stopping
Reverse-Torque: the projections and external member of this
disclosure used to counteract torque.
[0067] Common to most, but not all, of these embodiments is the
need to allow fluid flow-thru during the extension of the tool into
the radial borehole. For example, when actually drilling the radial
borehole itself drilling-fluid needs to reach the cutting head. On
the other hand, this disclosure can also be used to with
tool-strings that do not require fluid to reach the lower
tool-string. For example, a tool that is set into position within a
pre-created radial borehole by the application of a specific
weight, which the operator wants to assure has been attained by a
downhole weight indication means.
[0068] Having discussed the individual aspects of this disclosure,
let us turn now to a summary discussion of how the combinations of
these might be incorporated into a downhole tool-string system that
is used with radial boreholes--i.e. with boreholes that exit a
primary wellbore at between 45 to about 90 degrees.
[0069] In embodiments, this disclosure entails a fluid flow-thru
means and a means for dampening the forces/weight exerted on a
downhole tool-string used while in a radial boreholes.
[0070] In embodiments, this disclosure entails a fluid flow-thru
means and a torque-resisting system used in conjunction with a
downhole tool-string used while in a radial borehole.
[0071] In embodiments, this disclosure entails a weight indicator
means and a means to dampen the forces/weight applied on a downhole
tool-string used while in a radial borehole.
[0072] In embodiments, this disclosure entails a weight indicator
means and a spline for the transmission of torque through a
downhole tool-string used while in a radial borehole.
[0073] In embodiments, this disclosure entails a weight indicator
means and the means to resist torque generated from a rotating
downhole tool-string used while in a radial borehole.
[0074] In embodiments, this disclosure entails a spline to transfer
torque through a downhole tool-string and a means to dampen the
forces/weight exerted on a downhole tool-string used while in a
radial borehole.
[0075] In embodiments, this disclosure entails a means to resist
torque generated from a rotating downhole tool-string and to dampen
the forces/weight exerted on that tool-string used while in a
radial borehole.
[0076] In embodiments, this disclosure entails a fluid flow-thru
means, weight indicator means and a means to dampen the
forces/weight exerted on that tool-string used while in a radial
borehole.
[0077] In embodiments, this disclosure entails a fluid flow-thru
means, weight indicator means and a spline to transmit torque
through a downhole tool-string used while in a radial borehole.
[0078] In embodiments, this disclosure entails a fluid flow-thru
means, weight indicator means and the means to resist torque
generated from a rotating downhole tool-string used while in a
radial borehole.
[0079] In embodiments, this disclosure entails a fluid flow-thru
means, a spline to transfer torque through a downhole tool-string
and a means to dampen the forces/weight exerted on that tool-string
used while in a radial borehole.
[0080] In embodiments, this disclosure entails a fluid flow-thru
means, a means to resist torque generated from a rotating downhole
tool-string and a means to dampen the forces/weight exerted on that
tool-string used while in a radial borehole.
[0081] In embodiments, this disclosure entails a weight indicator
means, a means to resist torque generated from a rotating downhole
tool-string and a means to dampen the forces/weight exerted on that
tool-string used while in a radial borehole.
[0082] In embodiments, this disclosure entails a spline to transfer
torque to a downhole tool, a means to resist torque generated from
a rotating downhole tool-string and a means to dampen the
forces/weight exerted on that tool-string used while in a radial
borehole.
[0083] In embodiments, this disclosure entails a fluid flow-thru
means, a weight indicator means, a spline to transfer torque
through a downhole tool-string and a means to dampen the
forces/weight exerted on that tool-string used while in a radial
borehole.
[0084] In embodiments, this disclosure entails a fluid flow-thru
means, a weight indicator means, a means to resist torque generated
from a rotating downhole tool-string and a means to dampen the
forces/weight exerted on that tool-string used while in a radial
borehole.
[0085] In embodiments, this disclosure entails a fluid flow-thru
means, a spline to transfer torque through a downhole tool-string,
a means to resist torque generated from a rotating downhole
tool-string and a means to dampen the forces/weight exerted on that
tool-string used while in a radial borehole.
[0086] In embodiments, this disclosure entails a fluid flow-thru
means, a weight indicator means, a spline to transfer torque
through a downhole tool-string, a means to resist torque generated
from a rotating downhole tool-string and a means to dampen the
forces/weight exerted on that tool-string used while in a radial
borehole.
[0087] The embodiments above where the tool is placed below a motor
would require the spline be positioned below the motor. Similarly,
in the embodiments above where a torque-stopping means were
employed, this tool would be placed above the output shaft of the
motor.
[0088] FIG. 1 is a zoomed-out view illustrating the downhole tool
assembly (15) used in conjunction with a flexible drilling-string
(10) with attached drill-head (11). The system is deployed by a
control-line (2), in this case large-diameter coiled-tubing (2)
controlled by a coiled tubing unit (1a). The coiled tubing unit
(1a) can measure the pressure (1c) in the control-line (2) as well
as flow by virtue of an in-line flow meter (1b). Evident in the
figure is a wellbore (5), a wellhead (5b), production tubing (3), a
whipstock (9), an anchor (13) and the earthen formation (14) into
which a lateral borehole (12) is being drilled. In this case, the
downhole-tool assembly (15) consists of a weight indicator
sub-assembly sub (4) positioned above a downhole motor (6) and a
dampener sub-assembly (7) positioned below the downhole motor (6).
The dampener sub-assembly (7) is connected to the flexible
drill-string (10).
[0089] FIG. 2A a flexible drill-string (10), with attached
drill-head (11), is positioned in a lateral borehole (12). As the
drill-head (11) is not in contact with the earthen formation (14)
being drilled, there is no weight-on-bit (WOB).
[0090] FIG. 2B illustrate the flexible drill-string (10),
drill-head (11), earthen formation (14) and borehole (12) of FIG.
2A, but the drill-head (11) is in contact with and is drilling the
earthen formation (14) causing WOB.
[0091] FIG. 2C shows a cross-section of the apparatus of FIG. 2A
and how a flow path (16) and exit passageways (17) in the
drill-head (11) allow for fluid flow (as shown by arrows).
[0092] FIG. 3A illustrates a dampener sub assembly (7) comprising
of a tension spring (18) contained in a main housing (19). The main
housing (19) is connected to an upper housing (20) through which a
push-rod (21) can travel. The push-rod (21) is in turn connected to
an upper tool-string (22), while the main housing (19) is connected
to a lower tool-string (23). One end of the tension spring (18)
rests against the main housing (19) while the other end of the
spring (18) rests against a piston (24) that is connected to the
push-rod (21). A passage-way (25) through the push-rod (21), a
chamber (26) in the main housing (19) and an opening (27) in the
main housing (19) assure fluid flow (as shown by arrows) through
the dampener sub-assembly (7). There is no WOB on the lower tool
assembly (not shown but as exemplified in FIG. 2A) and hence the
tension spring (18) is fully-extended in the main housing (19).
[0093] FIG. 3B illustrates the same dampener sub assembly (7) as in
FIG. 3A. In this case, however, WOB has been applied to the end of
the lower tool-assembly (not shown but as exemplified in FIG. 2B).
This has caused the lower tool-string (23) and attached main
housing (19) to move upward (as shown by the arrow) relative to the
push-rod (21) and piston (24). In the process, the spring (18) has
been compressed between the piston (24) and main housing (19). The
spring (18) has thus acted to dampen the applied load (not shown)
on the lower tool-string (23).
[0094] FIG. 4 is an illustration in which the dampener subassembly
(7) comprises a gas-filled chamber (28) and transducer (29) to
report the load reading (not shown) to the equipment operator (not
shown, but at surface). This dampener assembly (7) has an upper
housing (20) that is connected to a main housing (19) in which is
are an upper chamber (30) and a lower chamber (31) that are
separated by a movable piston (24) attached to a push-rod (21). The
piston (24) has an o-ring seal (37) that seals against the inside
wall (33) of the main housing (19). The push-rod (21) also has an
o-ring (34) that seals against the top housing (20). A pressure
transducer (29) measures the pressure in the gas-filled chamber
(28) and reports this value (not shown) via a wire (35) running
inside of the control-line (2), which in this case is coiled
tubing. Fluid (shown by arrows) travels through the coiled tubing
(2), the push-rod (21), the lower chamber (31) and enters the lower
tool string (23). As WOB is applied (as indicated by the direction
of the arrow at left) to the downhole tool (not depicted here but
shown in FIG. 2B) the downhole tool moves the main housing (19)
upwards relative to the piston (24), compressing the gas (36) in
the upper chamber (30). The gas (36) in the upper chamber (30)
serves to dampen the load.
[0095] FIG. 5A illustrates a dampener sub-assembly (7) with
integrated weight indicator (38) shown inside of upset tubing (3)
in a no WOB condition of a downhole tool-string (not shown but
exemplified in FIGS. 2A and 2C). The dampener sub-assembly (7)
comprises a spring (18) that sits against a top rest (39). The top
rest (39) is attached to the control-line (2) and also to a
push-rod (21) that extends thru a main housing (19). An o-ring (34)
seals between the push-rod (21) and main housing (19). The spring
(18) pushes against the top (40) of the main housing (19). The
lower end (41) of the push-rod (21) extends through the main
housing (19) and through a barrier (42) that is securely affixed to
the main housing (19). An o-ring (43) seals between the barrier
(42) and the push-rod (21). A cylinder (44) is securely fixed to
the push-rod (21) and an o-ring (54) seals between the cylinder
(44) and the inside wall (33) of the main housing (19). This
arrangement defines an upper chamber (45), a middle chamber (46)
and a lower chamber (47). A lower housing (48) connects securely to
the main housing (19); the lower housing (48) is also securely
fixed to a lower tool-string (23). The middle chamber (46) has a
vent (49) in the main housing (19) so as to allow free travel of
the cylinder (44). Fluid or gas (shown by arrows) can flow from the
control line (2), through the push-rod (21) and cylinder (44) into
the lower chamber (47). A hole (50) in the lower housing (48)
allows flow (shown by arrow) from lower chamber (47) into the lower
tool-string (23). A lower port (51) crosses from the push-rod (21)
into the upper chamber (45), allows flow (shown by dotted-line
arrow) into the upper chamber (45) so as to balance the hydraulic
forces acting on the push-rod (21). A middle port (52) and upper
port (53) of known sizes and positions also traverse through the
push-rod (21). Without any WOB, the spring (18) is fully extended;
and as such, the middle port (52) and upper port (53) are venting
(as shown by dotted-line arrows) a known amount of fluid/pressure
out of the push-rod (21) and into the upset tubing (3), thereby
indicating to the equipment operator (not shown) a no WOB
condition.
[0096] FIG. 5B is illustrates of the dampener sub-assembly (7) of
FIG. 5A when a lower tool-string (23) is under a WOB condition (not
shown but exemplified in FIG. 2B). In this case, the main housing
(19) has moved upwards (as indicated by the vertical arrow at
left), compressing the spring (18). This has caused the middle port
(52) and upper port (53) to no longer vent into the upset tubing
(3) but instead they "vent" into the already-filled upper chamber
(45). This causes an increase in pressure and decrease in flow in
the control line (2) which can be measured at the surface by items
1b and 1c shown in FIG. 1, allowing the operator (not shown) to
know and control the WOB. That is, by using a spring (18) with a
known spring-rate and by knowing the placement and sizing of the
upper port (53) and middle port (52) the equipment operator (not
shown) can ascertain the WOB from changes to pressure and flow seen
by items 1b and 1c shown in FIG. 1.
[0097] FIG. 6A illustrates a dampener sub-assembly (7) similar to
that shown in FIGS. 5A and 5B. In this case, however, the dampener
sub-assembly (7) not only allows for dampening of applied forces,
indication of WOB (to the equipment operator at the surface) and
the transmission of fluid, but it also allows for the transmission
of torque. In this version, the dampener sub-assembly (7) consists
of a push-rod (55) the upper portion of the push rod (55a) has an
external spline (evident in FIG. 6D) so as to transmit torque to a
mating spline-nut (65), with internal splines (evident in FIG. 6B).
The upper portion of the push-rod (55a) runs through the mating
spline-nut (65) as shown in FIG. 6C. The spline-nut (65) is
securely affixed to the main housing (19) in order to transmit
torque to the main housing (19). The push-rod (55) defines a
passageway (56) for the passage of fluid or gas (shown by arrows)
to an attached lower tool-string (23). The push-rod (55) also
defines an upper port (53), middle port (52) and lower port (51)
that allow flow (as shown by dotted arrows). The top (57) of the
spline-rod (55) is connected to a top rest (39) and the top rest
(39) is connected to a downhole motor (6). As the downhole motor
(6) rotates the top rest (39), the attached spline-rod (55) is
rotated, rotating the spline-nut (65), attached main housing (19),
lower housing (48) and lower tool-string (23). Furthermore, in
operation, the spring (18) dampens the WOB while the spline-rod
(55) and mating spline-nut (65) assure the transmission of torque.
WOB is indicated by changes in pressure via upper port (53) and
middle port (52), as described in FIGS. 5A and 5B. The lower
portion (55b) of the push-rod (55) is without a spline (evident in
FIG. 6E).
[0098] FIG. 6B illustrates the FIG. 6A in cross-section at line B.
The spline nut (65) with internal spline teeth (66) can be
seen.
[0099] FIG. 6C illustrates the FIG. 6A in cross-section at line C.
Evident are the main housing (19), spline-nut (65), upper
spline-rod (55a), and the passageway (56) at the center. Torque is
transmitted via the mating spline teeth (66 and 67).
[0100] FIG. 6D illustrates a portion of the FIG. 6A in
cross-section at line D. Evident in this figure are the external
spline teeth (67) and inner passageway (56) of the upper push rod
(55a).
[0101] FIG. 6E illustrates a portion of the FIG. 6A in
cross-section at line E. Evident in this picture is the lower
portion of the spine-rod (55b) and inner passageway (56).
[0102] FIG. 7A illustrates an anti-torque tool (70) situated above
the output shaft (6f) of a downhole motor (6) for use with a
control-line (2) that poorly resists torque. The anti-torque tool
or projections (70) is wider (evident along line B) than the
downhole motor (6) and mates with an extended, rigid anti-torque
member (71) positioned below production tubing (3). The anti-torque
member (71) and anti-torque tool (70) when used in conjunction
provide continuous resistance to the reverse torque caused by the
drill-head (11) and flexible drill-string (10) when in operation.
The vertical length (shown by extended arrow at right) of the
anti-torque member (71) allows for the anti-torque tool (70) to
travel vertically along the anti-torque member (71) and thus this
system allows for continuous torque resistance as the downhole
motor (6) travels vertically. In this figure the drill-head (11) is
located above the whipstock (9) and a hole (5d) has previously been
cut in the casing (5c). The top of the downhole motor (6) is
connected to a weight indicator sub-assembly (4) which in turn is
connected to the control line (2), in this case coil tubing
(2).
[0103] FIG. 7B illustrates the same set up as FIG. 7A except in
this case a lateral borehole (12) is being drilled. The figure
shows that as the drill-head (11) cuts the lateral borehole (12)
the anti-torque tool (70) moves along the anti-torque member (71),
thereby providing continuous torque resistance so that the torque
does not twist the downhole motor (6) and thin control-line
(2).
[0104] FIG. 7C illustrates the apparatus of FIG. 7A in
cross-section at line B. As can be seen the anti-torque tool (70)
mates inside the rigid anti-torque member (71). The output shaft
(6f) and inner passageway (6e) of the downhole motor (6) are also
evident. The anti-torque tool (70) is securely affixed to the motor
(6) and rides along slots (72) in the anti-torque member (71).
[0105] In an embodiment of the present disclosure there is an
apparatus for dampening the force exerted on a tool-string when a
lower portion of said tool-string is in a subterranean lateral
borehole radiating outward at least 5 feet at an angle between 45
to about 90 degrees from a primary wellbore, the dampening
apparatus includes a housing, a push-rod and at least one dampening
member. The dampening member can be a tension spring, a compression
spring, a gas-filled chamber, an elastomeric material or a
magnet.
[0106] Optionally the apparatus can include one or more of the
following elements: a spring that extends when additional weight on
bit is applied at a cutting head, a spring that compresses when
additional weight on bit is applied at a cutting head, magnets
oriented such that they repel each other or a sealed gas-charged
chamber.
[0107] In an optional embodiment the apparatus includes an internal
hose running the length of the apparatus, one or more inner
passageways running the length of the apparatus, and a conduit
running the length of the apparatus external to the housing.
[0108] In an optional embodiment the apparatus includes one or more
anti-torque projections extending from the housing. The anti-torque
projections can provide continuous, low-drag movement when in
contact with an external member. The anti-torque projections in
contact with an external member resists applied torque.
[0109] In an optional embodiment the apparatus includes a
weight-on-bit measurement device. Optionally includes a
weight-on-bit measurement transmission device. The weight-on-bit
measurement transmission device can include changes in the pressure
of a drilling-fluid stream, changes in the flow of a drilling-fluid
stream and an electrical transmission line.
[0110] In an embodiment of the present disclosure there is a method
of dampening the force applied on a tool-string when a lower
portion of that tool-string is in a subterranean lateral borehole
radiating outward at least 5 feet at an angle between 45 to about
90 degrees from a primary wellbore, the method includes providing a
dampening apparatus comprising a housing, a push-rod, and at least
one dampening member. The method includes engaging the dampening
member. Engaging the dampening member can result in the extension
of a tension spring positioned in the dampening apparatus, the
compression of a spring positioned in the dampening apparatus, the
compression of a gas-filled chamber positioned in the dampening
apparatus, the compression of an elastomeric material positioned in
the dampening apparatus; overcoming the repulsion of two like-poled
magnets positioned in the dampening apparatus, or combinations
thereof.
[0111] In an alternate embodiment of the present disclosure there
is an apparatus for measuring the force exerted on a tool-string
when a lower portion of said tool-string is in a subterranean
lateral borehole radiating outward at least 5 feet at an angle
between 45 to about 90 degrees from a primary wellbore. The
measuring apparatus includes one or more ports that are
successively opened or closed based on changes in the applied force
and thereby causing a change in the pressure of a fluid within the
tool-string that can be measured.
[0112] In an alternate embodiment there is an apparatus for
measuring the force exerted on a tool-string when a lower portion
of said tool-string is in a subterranean lateral borehole radiating
outward at least 5 feet at an angle between 45 to about 90 degrees
from a primary wellbore. The measuring apparatus can include a
pressure transducer in the tool-string that reports either the
pressure in a gas or fluid-filled chamber or the pressure applied
by a spring in the apparatus.
[0113] In an alternate embodiment there is a method for measuring
the force exerted on a tool-string when a lower portion of said
tool-string is in a subterranean lateral borehole radiating outward
at least 5 feet at an angle between 45 to about 90 degrees from a
primary wellbore. The method includes making a first pressure
measurement made by a pressure measurement device. The pressure
measurement device can include changes in drilling fluid pressure
due to opening and closing of ports that vent said fluid, a
pressure transducer that measures pressure in a gas or fluid-filled
chamber, or a pressure transducer that measures the force applied
by a downhole spring and then transmitting the first pressure
measurement.
[0114] In an embodiment the transmission of the first pressure
measurement can be made through changes in pressure of a fluid
within the tool-string or through an e-line.
[0115] In an alternate embodiment there is an apparatus for the
transmission of torque in a drill-string used to form an extended
subterranean lateral borehole radiating outward at least 5 feet at
an angle between 45 to about 90 degrees from a primary wellbore.
The apparatus remains in the primary wellbore and includes an inner
spline member and an outer spline member. The inner spline member
is in contact with the outer spline member and there is a low
coefficient of drag between them.
[0116] In an alternate embodiment there is a method for the
transmission of torque in a drill-string used to form an extended
subterranean lateral borehole radiating outward at least 5 feet at
an angle between 45 to about 90 degrees from a primary wellbore.
The method includes providing a torque transmission apparatus
having an inner spline member and an outer spline member, the inner
spline member in contact with the outer spline member and having a
low coefficient of drag between them. Placing the torque
transmission apparatus within the drill-string in the primary
wellbore and connecting the torque transmission apparatus to a tool
string that extends into the lateral borehole.
[0117] In an alternate embodiment there is a system to improve the
efficiency of a tool-string used to form an extended subterranean
lateral borehole radiating outward at least 5 feet at an angle
between 45 to about 90 degrees from a primary wellbore. The system
includes at least one projection extending from the tool-string and
at least slot on an external device into which the at least one
projection can engage. When the projection engages with the slot
they resist a counter torque exerted on the tool-string.
[0118] In an alternate embodiment there is a system to improve the
efficiency of a tool-string used to form an extended subterranean
lateral borehole radiating outward at least 5 feet at an angle
between 45 to about 90 degrees from a primary wellbore. The system
includes a weight indicator and a load dampener. The system can
optionally include a load-balanced piston and a spring for
additional dampening. The system can optionally include a spline
mechanism for the transmission of torque.
[0119] The various embodiments of the present disclosure can be
joined in combination with other embodiments of the disclosure and
the listed embodiments herein are not meant to limit the
disclosure. All combinations of various embodiments of the
disclosure are enabled, even if not given in a particular example
herein.
[0120] While illustrative embodiments have been depicted and
described, modifications thereof can be made by one skilled in the
art without departing from the scope of the disclosure. All numbers
and ranges disclosed above may vary by some amount. Whenever a
numerical range with a lower limit and an upper limit is disclosed,
any number and any included range falling within the range is
specifically disclosed. In particular, every range of values (of
the form, "from about a to about b," or, equivalently, "from
approximately a to b," or, equivalently, "from approximately a-b")
disclosed herein is to be understood to set forth every number and
range encompassed within the broader range of values. Moreover, the
indefinite articles "a" or "an", as used in the claims, are defined
herein to mean one or more than one of the element that it
introduces. If there is any conflict in the usages of a word or
term in this specification and one or more patent or other
documents, the definitions that are consistent with this
specification should be adopted. While compositions and methods are
described in terms of "comprising," "containing," or "including"
various components or steps, the compositions and methods can also
"consist essentially of" or "consist of" the various components and
steps. Also, the terms in the claims have their plain, ordinary
meaning unless otherwise explicitly and clearly defined by the
patentee.
[0121] Depending on the context, all references herein to the
"disclosure" may in some cases refer to certain specific
embodiments only. In other cases it may refer to subject matter
recited in one or more, but not necessarily all, of the claims.
While the foregoing is directed to embodiments, versions and
examples of the present disclosure, which are included to enable a
person of ordinary skill in the art to make and use the disclosures
when the information in this patent is combined with available
information and technology, the disclosures are not limited to only
these particular embodiments, versions and examples.
[0122] Numerous other modifications, equivalents, and alternatives,
will become apparent to those skilled in the art once the above
disclosure is fully appreciated. While embodiments of the
disclosure have been shown and described, modifications thereof can
be made by one skilled in the art without departing from the
teachings of this disclosure. The embodiments described herein are
exemplary only, and are not intended to be limiting. Many
variations and modifications of the disclosure disclosed herein are
possible and are within the scope of the disclosure.
[0123] Use of the term "optionally" with respect to any element of
a claim is intended to mean that the subject element is required,
or alternatively, is not required. Both alternatives are intended
to be within the scope of the claim. It is intended that the
following claims be interpreted to embrace all such modifications,
equivalents, and alternatives where applicable. Other and further
embodiments, versions and examples of the disclosure may be devised
without departing from the basic scope thereof and the scope
thereof is determined by the claims that follow.
* * * * *