Note: Descriptions are shown in the official language in which they were submitted.
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DOVVNHOLE WIRELESS SYSTEM FOR TUNNELING
ARRANGEMENTS
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The invention relates generally to the use of wireless communication
systems
to assist in creating downhole tunnels and passages.
2. Description of the Related Art
[0002] Efforts have been made to enhance production or create new
production
from existing wells by forming an opening through the-casing of the wellbore
and
forming a tunnel through the formation beyond the casing. Tunneling
arrangements
which incorporate articulated joints largely prevent sensors from being
effectively
incorporated at or near the distal tunneling tool itself.
SUMMARY OF THE INVENTION
[0003] The invention provides tools and methods useful for creating tunnels
within
a formation surroundings a wellbore using a tunneling tool with one or more
articulating
joints. An exemplary jointed tunneling arrangement is described having a
tunneling
tool through which acid or fluids containing solids (i.e., sand) can be
injected under
high pressure through a distal nozzle to form a lateral tunnel. In other
embodiments,
a milling or directional drilling tool incorporates such articulating joints.
[0004] Wireless data communication is employed which permits sensors to be
located proximate the nozzle of the tunneling tool and have sensor data
transmitted
across one or more articulating tool joints. In described embodiments, a
wireless
transmitter and wireless receiver are incorporated into the tunneling tool so
as to
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transmit sensor data across at least one articulating joint of the tool.
Sensors can
detect one or more wellbore parameters, including angular orientation of the
tunneling
tool, pressure, temperature, location of the tunneling tool, minerology
(gamma) and
acidity (pH) of the acid entering the formation. Data is transmitted to a
controller at
surface via a data communication conduit, such as tubevvire, or via other
means. The
wireless communication of the present invention allows for collection of
better
information since it permits sensors to be located at or near the distal end
of the tool
while data from the sensors is transmitted across an articulating joint. This
data is
useful for controlling and steering the tool.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] For a thorough understanding of the present invention, reference is
made to
the following detailed description of the preferred embodiments, *taken in
conjunction
with the accompanying drawings, wherein like reference numerals designate like
or
similar elements throughout the several figures of the drawings and wherein:
[0006] Figure 1 is a side, cross-sectional view of an exemplary wellbore
containing _
a tunneling tool in accordance with the present invention.
[0007] Figure 2 is a side, cross-sectional view of an exemplary
tunneling tool in
accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0008] Figure 1 illustrates an exemplary wellbore 10 which has been
drilled through
the earth 12 from the surface 14 to a hydrocarbon-bearing formation 16. The
wellbore
10 is lined with metallic casing 18. In the depicted embodiment, it is desired
to
increase hydrocarbon production from the wellbore 10 by forming one or more
tunnels
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within the formation 16 through which hydrocarbons can then enter the wellbore
10
through lateral window 20. In the arrangement shown in Figure 1, a window 20
has
previously been formed using a sidetracking mill, an abrasive perforator, or
other
means known in the art.
[0009] A tunneling arrangement, generally indicated at 22, is shown disposed
within
the wellbore 10 in Figure 1. The tunneling arrangement 22 includes a running
string
24, which is preferably formed of coiled tubing. A coiled tubing running
string 24 is
injected from surface by a coiled tubing injector (not shown) of a type known
in the art.
A flowbore 26 is defined along the length of the running string 24 to permit
acid or fluid
containing solids, such as sand, to be injected through the flowbore 26. A
data
communication conduit 28 is located within the flowbore 26 of the running
string 24.
Preferably, the data communications conduit 28 is tubewire. Telecoil is
coiled tubing
which incorporates tubewire that can transmit power and data. Tubewire is
available
commercially from manufacturers such as Canada Tech Corporation of Calgary,
Canada. In some embodiments, the tubewire incorporates an optical fiber for
data
transmission. Tubewire can transmit data along its length as well as
electrical power.
[0010] A tunneling tool 30 is affixed to the distal end of the running string
24. The
tunneling tool 30 is employed to form one or more tunnels within the formation
16
through window 20 in the casing 18. An exemplary tunneling tool 30 is depicted
in
greater detail in Figure 2. It is noted that the particular tunneling tool 30
which is shown
is an acid injection tunneling tool which uses acid, injected through the tool
at high
pressures, to create tunnels within the formation 16. It is noted that, in
other
embodiments, a tunneling tool may use sprays of fluid containing sand or other
solids
to form tunnels. In other embodiments, the tunneling tool 30 may comprise a
rotary
drilling or milling bit.
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[0011] Generally, the tunneling tool 30 includes a main body portion 32
which
secures to the running string 24. An intermediate body portion 34 is secured
to the
main body portion 32 by a first articulating joint 36. A lower body portion 38
is secured
to the intermediate body portion 34 by a second articulating joint 40. The
first and
second articulating joints 36, 40 allow the body potions which they join to
move
angularly with respect to one another. It is noted that the lower body portion
38 and
the main body portion 32 are separated from each other by at least one
articulating
joint which permits relative angular movement between the lower body portion
38 and
the main body portion 32. The lower body portion 38 may be thought of as a
first body
portion and the main body portion 32 may be thought of as a second body
portion
which is separated from the first body portion by at least one articulating
joint (i.e., 36,
and/or 40) which permits angular movement between the first and second body
portions. An axial fluid flowpath 42 is defined through the tunneling tool 30.
Nozzle
44 is positioned at the distal end of the lower body portion 38 and is useful
to direct
sprays of acid into the formation 16 to form tunnels. Acid is communicated
from the
flowbore 26 of the running string 24 to the nozzle 44 via flowpath 42. The
acid is
flowed from surface 14 under the impetus of a fluid pump (not shown) at
surface, of a
type known in the art. The pumping pressure of the fluid pump can be adjusted
(increased or decreased) as desired by an operator.
[0012] The first and second articulating joints 36, 40 allow the body portions
that are
affixed to them to bend and flex angularly relative to each other. In the
depicted
embodiment, there are two articulating joints 36, 40. It is noted, however,
that the
devices and methods of the present invention might also be applied to tools
which
incorporate only a single articulating joint or more than two articulating
joints. It is
noted that the use of multiple articulating joints is preferred since it
allows three
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dimensional freedom of movement of the hozzle 44 with respect to the main body
portion 32 during operation. Each of the articulating joints 36, 40 is
preferably a
pressure-operated knuckle joint.
[0013] As Figure 1 shows, a controller 46 is located at surface 14 and
is
interconnected with the data communication conduit 28 so as to receive data
therefrom. The data communication conduit 28 is also operably associated with
a
telemetry sub 48 within the main body portion 32 of the tunneling tool 30. The
main
body portion 32 also preferably includes an indexing tool 50 which can rotate
the
tunneling tool 30 angularly with respect to the running string 24. The
controller 46 is
to preferably a programmable digital device, such as a computer, which can
remotely
control (i.e., from surface) the indexing tool 50 and thus the angular
orientation of the
tunneling tool 30.
[0014] Sensors 52 are incorporated into the lower body portion 38. Preferably,
at
least some of the sensors 52 are located at or near the distal end of the
lower body
portion 38 proximate the nozzle 44. The sensors 52 are configured to detect
one or
more of the wellbore parameters which include temperature, pressure,
acceleration of
the nozzle 44 and angular orientation of the nozzle 44, location of the
tunneling tool
30, and minerology (gamma). In addition, the wellbore parameters sensed by the
sensors 52 can include the acidity (pH) of the acid entering the formation 16
from the
nozzle 44. The sensors 52 can transmit to surface 14 real-time data regarding
tunnel
mapping. Tunnel mapping data can include information relating to the tunnel
orientation, length and formation properties (pressure, temperature and
minerology).
Based upon the tunnel orientation and length, the coiled tubing operator can
decide if
the tunnel forming should continue or if the tunneling tool 30 should be
steered in a
new direction by rotating the indexing tool 50. A wireless transmitter 54 is
also
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incorporated into the lower body portion 38 and is operably associated with
the
sensors 52 to receive data from the sensors 52 and generate a wireless signal
or
signals representative of the data. Sensors can detect angular orientation,
pressure,
temperature or other downhole parameters.
[0015] A wireless receiver 56 is housed within the telemetry sub 48 and is
operable
to receive wireless signals generated by the wireless transmitter 54. The
wireless data
link between the transmitter 54 and the receiver 56 can be any form or
protocol of
wireless data communication that is effective to convey data across rotating
or bending
joints in a tool string. Wireless communication media is preferably radio
wireless, but
io might also include optical, or sound-based wireless communications.
Wireless
telemetry is used to record and transmit, in real time, at least some of the
parameters
which include the location, speed, acceleration, and inclination of the lower
body
portion 38 or the volume and/or pH of the acid being injected into the
formation 16.
[0016] Data sensed by the sensors 52 is preferably transmitted from the
wireless
is receiver 56 to the controller 46 at surface via data communications
conduit 28.
Alternatively, the data might be transmitted to the controller 46 via fiber
optic or other
electrical wiring or even mud pulse telemetry.
[0017] Data received by the controller 46 from the sensors 52 is useful for
controlling
and/or steering the nozzle 44 of the tunneling tool 30. Data received by the
controller
20 46 will indicate to an operator how a tunnel is developing (direction,
length, angular
orientation). In accordance with preferred methods, data relating to tunneling
is used
to control at least one aspect of operation of the tunneling tool 30.
Controlling aspects
of operation of the tunneling tool 30 include at least one of: altering the
angle or
direction of the tunneling tool, adjusting acid flow rate to the tunneling
tool, and
25 adjusting weight on bit. The weight on bit is typically maintained above
a minimum
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value that guarantees that the coiled tubing doesn't buckle and can be changed
from
surface based on the real-time monitoring of such parameters as pumping rate,
formation minerology/heterogeneity and tunnel shape/size. Depending on the
real-
time tunnel mapping, a coiled tubing operator could control/steer the
tunneling tool 30
such that acid flowing out through the nozzle 44 will dissolve formation rock
from a
different angle, changing the orientation of the tunnel being formed. If the
inclination
of the tunnel/tunneling tool 30 is not as desired, the controller 46 could
command the
indexing tool 50 to rotate to correct the issue. The indexing tool 50, as well
as the
articulating joints 36, 40 are typically pressure-activated from surface and
can be
controlled by varying fluid pressure from surface 14. Alternatively, the
indexing tool
50 and articulating joints 36, 40 could be electrically actuate via electrical
power
supplied from the surface 14. Based upon real time data showing the length of
the
tunnel being created, the acid pumping rate can be adjusted to increase or
decrease
the rate of tunnel formation.
.. [0018] The invention provides a tunneling arrangement which includes at
least first
and second body portions that are affixed by one or more articulated joints. A
wireless
transmitter 54 is incorporated into a first body portion (i.e., lower body
portion 38), and
a wireless receiver is incorporated into a second body portion (i.e., main
body portion
32). There may be any number of intermediate portions, such as intermediate
body
portion 34, which are located between the first body portion and the second
body
portion.
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