Note: Descriptions are shown in the official language in which they were submitted.
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APPARATUS AND METHOD FOR GENERATING DOWNHOLE
FLUID PRESSURE PULSES
BACKGROUND
[0001] The present invention relates to apparatus for use in generating a
fluid pressure
pulse downhole comprising a tubular housing defining an internal fluid flow
passage and a
device for selectively generating a fluid pressure pulse located in a wall of
the housing. The
present invention also relates to a downhole data acquisition and telemetry
system comprising
such an apparatus, and at least one sensor. The present invention also relates
to a method of
measuring at least one parameter downhole in a wellbore and of transmitting
data relating to
the at least one parameter to surface.
[0002] In the oil and gas exploration and production industry, a wellbore is
drilled
from surface utilizing a string of tubing carrying a drill bit. Drilling fluid
known as drilling
'mud' is circulated down through the drill string to the bit, and serves
various functions. These
include cooling the drill bit and returning drill cuttings to surface along an
annulus formed
between the drill string and the drilled rock formations.
[0003] It is well known that the efficiency of oil and gas well drilling
operations can
be significantly improved by monitoring various parameters pertinent to the
process. For
example, information about the location of the borehole is utilized in order
to reach desired
geographic targets. Additionally, parameters relating to the rock formation
can help
determine the location of the drilling equipment relative to the local
geology, and thus correct
positioning of subsequent wellbore-lining tubing. Drilling parameters such as
Weight on Bit
(WOB) and Torque on Bit (TUB) can also be used to optimize rates of
penetration.
[0004] For a number of years, measurement-whilst-drilling (MWD) has been
practiced using a variety of equipment that employs different methods to
generate pressure
pulses in the mud flowing through the drill string. These pressure pulses are
utilized to
transmit data relating to parameters that are measured downhole, using
suitable sensors, to
surface. Systems exist to generate 'negative' pulses and 'positive' pulses.
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[0005] Many previous methods have involved placing some, or all, of the
apparatus in a probe, and locating the probe down the center of the drill-
pipe. This
leads to inevitable wear and tear on the apparatus, primarily through the
processes
of erosion, and also often through excessive vibration experienced during the
drilling operation. The cost of operating MWD equipment is therefore often
determined by the required flow rates and types of mud employed during the
drilling process. Furthermore, as the pipe is obstructed by the MWD equipment,
it
is impossible to pass through other equipment such as is often required for a
variety of purposes.
Examples of this include logging tools for the method
commonly referred to as 'through bit logging'. Other examples such as
diverting
valves can be activated by dropping activation devices through the thru bore
MWD
equipment (these activation devices are commonly balls of a variety of
diameters).
[0006] Apparatus has been developed for generating a fluid pressure pulse
downhole in which a pulse generating device is located at least partly in a
space
provided in a wall of an elongate, generally tubular housing. Apparatus of
this type
is disclosed in the Applicant's International Patent Publication No. WO-
2011/004180. The apparatus disclosed in WO-2011/004180 offers significant
advantages over prior apparatus and methods, in that locating the pulse
generating
device in the space in the wall of the tubular housing reduces exposure of the
device to fluid flowing through the housing, and thereby erosion of components
of
the apparatus, particularly the pulse generating device. Additionally,
location of the
device in the space facilitates the passage of fluid or other downhole objects
(such
as downhole tools, or actuating devices such as balls or darts) along the
fluid flow
passage defined by the housing.
[0007] There is a desire to further improve upon the apparatus disclosed in
WO-2011/004180. In particular, the device disclosed in WO-2011/004180
typically
requires that the wall of the tubular housing be of greater thickness than
uphole/downhole portions of the housing, in order to provide a sufficiently
large
space to receive the device. In one instance this can be achieved by forming
an
'upset' or shoulder, which typically either extends outwardly from an external
surface of the housing, or inwardly into the internal tubing bore (or possibly
both).
In another instance this can be achieved my mounting the apparatus in a
constant
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external diameter tubular (or 'slick OD' tubular) of sufficient wall
thickness, such as
a drill collar.
[0008] It is preferable to form an upset on the external surface of the
housing, so as to avoid restricting the internal tubing bore. However, this
requires
that the downhole tubing (or wellbore) into which the apparatus is deployed be
of
sufficiently large diameter all the way down to the placement point for the
apparatus. This diameter might be larger than would otherwise be dictated by
the
overall well design, or features of other components deployed into the well.
Furthermore, in certain scenarios, such as where a restriction exists in the
wellbore
uphole of the desired placement point for the apparatus, it may not be
possible to
provide the required clearance.
[0009] As a result, an internal upset is employed, extending into the
internal tubing bore. Following completion of a downhole procedure involving
the
measuring of a downhole parameter or parameters, and the transmission of data
to
surface employing the pulse generating device, there is a desire to provide
full bore
access through the tubular member. The full bore might be required for the
passage of tools or equipment to a position downhole of the apparatus, and for
improving fluid flow.
[0010] One proposal is to mill away the components of the apparatus
protruding into the internal bore, and so: the upset; at least part of the
pulse
generating device; and associated control/power equipment. This is undesirable
for
various reasons, including: the milling operation can take time as the pulse
generating device comprises components made from relatively hard materials;
the
debris from the milling operation can cause problems downhole; and milling
batteries in the device (typically lithium based) may not be acceptable either
from
an environmental or safety perspective. Indeed, for safety reasons it is
advisable
that the batteries be mounted beyond the milling path.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The following figures are included to illustrate certain aspects of the
present disclosure, and should not be viewed as exclusive embodiments. The
subject matter disclosed is capable of considerable modifications,
alterations,
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combinations, and equivalents in form and function, without departing from the
scope of this disclosure.
[0012] Fig. 1 is a schematic longitudinal sectional view of a downhole
assembly, comprising apparatus for generating a fluid pressure pulse downhole,
in
accordance with an embodiment of the present invention, the apparatus shown in
use during the completion of a well in preparation for the production of well
fluids;
[0013] Fig. 2 is an enlarged, perspective view of the apparatus shown in
Fig. 1;
[0014] Fig. 3 is a longitudinal cross-sectional view of the apparatus of Fig.
2, taken in the direction B-B;
[0015] Fig. 4 is an enlarged, highly schematic view of parts of the
apparatus of Fig. 2, taken in the direction A-A;
[0016] Fig. 5 is a detailed longitudinal sectional view of the apparatus of
Fig. 2, showing a pulse generating device of the apparatus in more detail;
[0017] Fig. 6 is a further enlarged view of part of the device shown in Fig.
5;
[0018] Fig. 7 is a further enlarged view of part of the device shown in Fig.
5;
[0019] Fig. 8 is a further enlarged perspective view of part of the
apparatus shown in Fig. 5, with certain internal components shown in ghost
outline;
[0020] Fig. 9 is an enlarged view of part of a wellbore of the well shown in
Fig. 1, which has been underreamed, showing the apparatus located in the
underreamed section;
[0021] Fig. 10 is a sectional view through part of an apparatus for
generating a fluid pressure pulse downhole in accordance with another
embodiment
of the present invention, with a device of the apparatus shown in a retracted
position;
[0022] Fig. 11 is a further enlarged view of part of the apparatus shown in
Fig. 10; and
[0023] Fig. 12 is a view of the apparatus of Fig. 10, with the device shown
in a radially extended position.
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DETAILED DESCRIPTION
[0024] According to a first aspect of the present invention, there is
provided apparatus for use in generating a fluid pressure pulse downhole, the
apparatus comprising:
[0025] a tubular housing defining an internal fluid flow passage, the
housing having a housing wall; and
[0026] a device for selectively generating a fluid pressure pulse, the device
mounted in a space in the wall of the tubular housing for movement between:
[0027] a retracted position; and
[0028] a radially extended position.
[0029] Mounting the pulse generating device for movement between such
retracted and extended positions provides the advantage that a maximum width
dimension (e.g. diameter) described by the apparatus can be arranged to be
less
when the device is in the retracted position, facilitating deployment of the
apparatus along a wellbore to a desired placement point. Following location at
the
desired placement point, the device can be moved to the radially extended
position.
Advantageously therefore, the invention provides the ability to open up access
through the tubular housing (and so through the apparatus) when the device is
in
the extended position.
[0030] The retracted position may be an operating position of the device,
in which the device can be employed to generate fluid pressure pulses
representative of at least one parameter measured downhole in the well. The
device may be moved to the extended position following operation to generate
such
fluid pressure pulses. However, it will be understood that the device may be
equally (or alternatively) capable of generating fluid pressure pulses when in
the
extended position. In the extended position, an outer surface of the device
may be
disposed beyond the external surface of the housing.
[0031] In the radially extended position, at least part of the device may
extend beyond an external surface of the housing. The tubular housing may have
an internal surface and an external surface, and the space may be defined by
an
aperture in the wall of the housing extending between the internal surface and
the
external surface. The aperture may have an opening in the internal surface of
the
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tubular housing, and an opening in the external surface of the tubular housing
which communicates with the opening in the internal surface. The openings may
be
of similar or different dimensions, profile and/or shape.
The aperture may
communicate with the internal passage, and may open on to the passage.
[0032] In the retracted position, the pulse generating device may not
extend beyond the external surface of the tubular housing. The device may
therefore be retracted into the space, and may not protrude beyond the
external
surface out of the space. Advantageously therefore, the invention provides the
ability to navigate a wellbore without requiring that the wellbore be larger
than
might otherwise be the case, to accommodate the apparatus. In the retracted
position, the device may extend a first distance beyond the external surface
of the
tubular housing; and in the extended position, the device may extend a second
distance beyond the external surface of the tubular housing which is greater
than
said first distance.
[0033] In the retracted position, the pulse generating device may extend
beyond the internal surface of the tubular housing and into the internal fluid
flow
passage. In the extended position, the device may not extend beyond the
internal
surface of the tubular housing and so may not extend into the internal fluid
flow
passage. Advantageously therefore, the invention provides the ability to open
full
bore access through the tubular housing (and so through the apparatus) when
the
device is in the extended position. In the retracted position, the device may
extend
a first distance beyond the internal surface of the tubular housing and into
the
internal fluid flow passage; and in the extended position, the device may
extend a
second distance beyond the internal surface of the tubular housing and into
the
internal fluid flow passage, said second distance being smaller than said
first
distance.
[0034] The pulse generating device may be releasably mounted to the
tubular housing in the space.
[0035] The apparatus may comprise a mounting member (such as a
mounting block) which receives the device, the mounting member mounted for
movement between the retracted and extended positions. Mounting of the device
in the mounting member may thus facilitate movement of the device between its
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retracted and extended positions. The device may comprise or may take the form
of a cartridge which can be: a) releasably movably mounted in the space; or b)
releasably mounted in the mounting member. The mounting member may be a
floating mounting member (and may in particular be a floating block), mounted
for
floating movement in the space under applied fluid pressure. In the extended
position, part of the mounting member may extend beyond the external surface
of
the housing. In particular, an outer surface of the mounting member may be
disposed beyond the external surface of the housing.
[0036] The device may be initially restrained in the retracted position. The
device may be initially restrained by at least one latch element, which may be
a dog
or pin. Said latch element may be actuable to release the device for movement
to
the extended position. Said latch element may be movable between an engaging
position where it restrains the device and a release position where the device
is
released for movement to the extended position. Said latch element may be
shearable or breakable to release the device for movement to the extended
position. Where the apparatus comprises a mounting member for the device, said
latch element may cooperate with the mounting member for restraining the
device.
[0037] The apparatus may be arranged so that the device can be
restrained in the extended position. The apparatus may be arranged to
automatically restrain the device in the extended position following movement
to
said position. The device may be restrained by at least one latch element,
which
may be a dog or pin. Said latch element may be actuable to restrain the device
in
the extended position. Said latch element may be movable between: a release
position, in which movement of the device to the extended position is
permitted;
and an engaging position where it restrains the device in the extended
position.
Said latch element may be shearable or breakable to permit release of the
device
for movement from the extended position back to the retracted position. Where
the apparatus comprises a mounting member for the device, said latch element
may cooperate with the mounting member for restraining the device.
[0038] Said latch elements may be provided in the tubular housing, in the
device (such as in the mounting member), or optionally latch elements may be
provided in both the housing and the device. Actuation options for the latch
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elements described above may include mechanical, electrical,
electromechanical,
hydraulic and combinations thereof.
[0039] The device may be mounted in the space in such a way that
movement of the device within or relative to the tubular housing, in
particular the
space, is restricted. The space may be a recess or pocket defined in the wall
of the
housing. The apparatus may be configured so that the device is movable from
the
retracted position to the radially extended position by imparting an expansion
force
on the tubular housing, in particular on a part of the tubular housing
defining the
space. Movement to the extended position may therefore be achieved by
expansion of the tubular housing (or part thereof).
[0040] The device may form part of an external surface of the housing, or
may be located in a portion of the housing which defines part of the external
surface, and which surface part may be moved radially outwardly when the
device
is moved to the extended position. The tubular housing may be configured so
that
it is expandable to thereby permit movement of the device to the extended
position. The tubular housing may comprise at least one deformation zone which
is
configured to deform so that the device can move to the extended position. The
deformation zone may be provided between a part of the tubular housing which
defines the space, and a further part of the tubular housing, which may be a
main
part or majority of the housing. There may be a zone or zones of deformation
bordering the space around an entire perimeter of the space.
[0041] The deformation zone may be a region of the tubular housing which
is shaped so that it can deform to permit radially outward movement of the
device,
to its extended position. The tubular housing may be shaped to define at least
one
corrugation, fold (or the like) in the deformation zone, said corrugation
arranged so
that it can be at least partially opened out or extended on exertion of an
expansion
force, so that the device can move to the extended position. The space may be
elongate in a direction along a longitudinal axis of the housing, and there
may be at
least one of said corrugations bordering lateral sides of the space and
extending in
a direction along said longitudinal axis.
[0042] The at least one deformation zone may comprise a material having
at least one material property which differs from a corresponding property of
a
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remainder or majority of the housing, and in particular from the part of the
housing
defining the space. The material property may be yield strength, and the at
least
one deformation zone may comprise a material having a lower yield strength
than
the remainder/majority of the housing. This may encourage the tubular housing
to
deform in the deformation zone on application of an expansion force. The at
least
one deformation zone may comprise portions which are formed from different
materials.
[0043] The apparatus may comprise at least one sensor for measuring a
downhole parameter, data relating to the parameter measured by the sensor
being
transmitted to surface via fluid pressure pulses generated by the pulse
generating
device. Said sensor may be provided as part of the device, or separately and
coupled to the device. Where the apparatus comprises a mounting member for the
pulse generating device, the sensor may be provided on or in the mounting
member.
[0044] The device may be movable under applied fluid pressure, e.g. by
creating a pressure differential between fluid in the internal fluid flow
passage
relative to fluid externally of the tubular housing. The aperture may define a
cylinder which receives the device, and the device may form a piston which is
movable within the cylinder by the application of fluid pressure. Suitable
seals may
be provided between the piston and a wall or walls of the aperture. Where the
apparatus comprises a mounting member, the mounting member may define the
piston. The tubular housing may be deformable in the at least one deformation
zone by applied fluid pressure. The device may be movable from the retracted
position to the extended position by applied fluid pressure. The device may be
movable from the extended position to the retracted position by applied fluid
pressure.
[0045] The device may be movable from the retracted position to the
extended position via application of a mechanical force, such as by passing an
expansion tool or element through the internal fluid flow passage, the tool
imparting a force on: a) the device located in the aperture, to urge it to the
extended position; or b) the part of the tubular housing defining the space,
to
thereby deform the housing in the at least one deformation zone. The device
may
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be movable from the extended position back to the retracted position via
application of mechanical force, such as via contact between the device and a
feature in the wellbore. The feature may be a dedicated feature (such as an
upset
or profile) provided in the wellbore for imparting a force on the device.
[0046] The apparatus may comprise a plurality of devices for generating a
fluid pressure pulse. Each device may be located in a respective space. A
plurality
of devices may be located in one space. Where the apparatus comprises a
mounting member, the mounting member may receive a plurality of pulse
generating devices.
[0047] The tubular housing may define an external upset which forms at
least part of the external surface of the housing. The tubular housing may
define
an internal upset which forms at least part of the internal surface of the
housing.
[0048] The apparatus may further comprise an operating unit arranged to
operate the device. The operating unit may comprise a source or sources of
electrical power (such as a battery), a data acquisition system, sensor(s) and
a
connector element which serves for electrically coupling the power source(s)
to the
device and for communicating with the device. The operating unit may be
mounted
in the or a space. Where the apparatus comprises a mounting member, the
operating unit may be mounted on or in the mounting member.
[0049] The device may be for controlling the flow of fluid along a flow path
which communicates with the internal fluid flow passage, to generate a fluid
pressure pulse. The device may comprise a valve having a valve element and a
valve seat, the valve being actuable to control the flow of fluid along the
flow path.
This may be achieved by moving the valve element into or out of sealing
abutment
with the valve seat. The device may comprise an actuator element which is
operable to move the valve element to thereby control the flow of fluid
through the
flow path. The actuator element may be electrically operated (and may for
example be a solenoid or motor) and coupled to the source of electrical power
in
the operating unit. Positive or negative fluid pressure pulses may be
generated by
the device. Positive pulses may be generated by operating the device to close
the
respective flow path, and negative pulses by operating the devices to open the
flow
path. The device may be in the form of a cartridge or insert. The cartridge
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house the valve. The device may define at least part of the flow path. The
device
may define the outlet. The inlet of each flow path may open on to the internal
fluid
flow passage. The outlet may open on to an exterior of the housing. The outlet
may open on to the internal fluid flow passage at a position which is spaced
axially
along a length of the housing from the inlet.
[0050] The apparatus may comprise a carrier mounted in the space, and
one or more of: the fluid pressure pulse generating device; a source of
electrical
power (e.g. battery); electronics and sensors or sensor assemblies may be
mounted in the carrier.
[0051] According to a second aspect of the present invention, there is
provided a downhole data acquisition and telemetry system comprising:
[0052] apparatus for use in generating a fluid pressure pulse downhole
according to the first aspect of the invention; and
[0053] at least one sensor for measuring a downhole parameter, data
relating to the parameter measured by the sensor being transmitted to surface
via
fluid pressure pulses generated by the pulse generating device.
[0054] Further features of the apparatus and sensor forming part of the
system of the second aspect of the invention are defined above in relation to
the
first aspect of the invention.
[0055] It will be understood that a sensor or sensors may be provided
which are capable of measuring a wide range of different parameters in a
wellbore,
including but not restricted to: pressure (e.g. in the internal bore and/or
externally
of the tubular housing); temperature; geological features (e.g. rock
resistivity,
background radiation); density; force (e.g. an axially directed force such as
a
weight applied to a component in the wellbore, which might be weight on bit
(WOB), or a rotationally directed force or torque applied to a component in
the
wellbore, which might be torque on bit (TOB) or in wellbore tubing); strain;
stress;
acceleration; and wellbore geometry features (e.g. rotational orientation or
'azimuth', inclination, the depth of a particular component or feature).
[0056] According to a third aspect of the present invention, there is
provided a method of measuring at least one parameter downhole in a wellbore
and
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of transmitting data relating to the at least one parameter to surface, the
method
comprising the steps of:
[0057] mounting a device for generating a fluid pressure pulse within a
space in a wall of a tubular housing which defines an internal fluid flow
passage;
[0058] running the housing into the wellbore with the device in a retracted
position, and locating the device at a desired position in the wellbore;
[0059] following location of the device at the desired position, operating
the device to generate fluid pressure pulses to transmit data relating to at
least one
downhole parameter to surface; and
[0060] moving the pulse generating device from the retracted position to a
radially extended position.
[0061] The step of moving the pulse generating device to the extended
position may take place following transmission of said data to surface. The
step of
moving the pulse generating device to the extended position may take place
prior
to transmission of said data to surface.
[0062] The method may comprise the further step of subsequently moving
the device from the extended position back to the retracted position.
[0063] The space may take the form of an aperture extending between an
internal surface of the housing and an external surface of the housing, and
the
method may comprise movably mounting the device within the aperture, and
locating the device in a retracted position in the aperture (which is the
retracted
position defined above). In the radially extended position, at least part of
the
device may extend beyond an external surface of the housing.
[0064] The device may be moved to the extended position by expansion of
the tubular housing, or part thereof, in particular a part defining the space.
The
device may be moved to the extended position by deforming the tubular housing
in
a deformation zone or zones.
[0065] The step of moving the device to the extended position may
comprise applying fluid pressure to the device to urge it to the extended
position.
This may involve creating a pressure differential between fluid in the
internal fluid
flow passage relative to fluid externally of the tubular housing. The method
may
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comprise the further step of subsequently moving the device from the extended
position back to the retracted position by applying fluid pressure to the
device.
[0066] The step of moving the device to the extended position may
comprise applying a mechanical force to the device to urge it to the extended
position. This may involve passing an expansion tool or element through the
internal fluid flow passage (which may be actuable e.g. under fluid pressure),
the
tool imparting a force on the device to urge it to the extended position. The
device
may form part of an external surface of the housing, or may be located in a
portion
of the housing which defines part of the external surface, and which surface
part
may be moved radially outwardly when the device is moved to the extended
position. The method may comprise the further step of subsequently moving the
device from the extended position back to the retracted position, by applying
a
mechanical force to the device. This may involve bringing the device into
contact
with a feature in the wellbore.
[0067] The method may comprise initially restraining the device in the
retracted position. The device may be initially restrained by at least one
latch
element. Said latch element may be actuated to release the device for movement
to the extended position. Said latch element may be sheared or broken to
release
the device for movement to the extended position, such as via the application
of a
mechanical force.
[0068] The method may comprise restraining the device in the extended
position. The device may be restrained using at least one latch element. Said
latch
element may be selectively actuated to restrain the device in the extended
position.
Said latch element may be sheared or broken to permit release of the device
for
movement from the extended position back to the retracted position.
[0069] Further features of the method of the third aspect of the invention
may be derived from or with respect to the text set out above relating to the
apparatus and/or system of the first/second aspect of the invention.
[0070] Turning firstly to Fig. 1, there is shown a downhole assembly
indicated generally by reference numeral 10, the assembly comprising an
apparatus
for generating a fluid pressure pulse downhole in accordance with an
embodiment
of the present invention, and which is indicated generally by reference
numeral 12.
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As will be described in more detail below, the apparatus 12 has a particular
utility in
transmitting data relating to one or more parameters measured in a downhole
environment to surface.
[0071] In the illustrated embodiment, the assembly 10 takes the form of a
tubing string and is shown in use, during the completion of a wellbore or
borehole
14. In the drawing, a main portion 16 of the wellbore 14 has been drilled from
surface, and lined with wellbore-lining tubing known as casing 18, which
comprises
lengths or sections of tubing coupled together end-to-end. The casing 18 has
been
cemented in place at 20, in a known fashion. The wellbore 14 has then been
extended, as indicated by numeral 22, by drilling through a section of tubing
24 at
the bottom of the wellbore (known as a casing 'shoe') and through a cement
plug
26 which surrounds the casing shoe.
[0072] A smaller diameter wellbore-lining tubing known as a liner 28 has
then been installed in the extended portion 22 of the wellbore, suspended from
the
casing 18 by means of a liner hanger 30. The liner 28 is shown prior to
cementing
in place, cement used to seal the liner (not shown) passing up an annulus 32
defined between a wall 34 of the drilled wellbore and an external surface 36
of the
liner. The cement passes up along the annulus 32 and into the casing 24, at a
level
which is below (i.e. deeper in the well) the liner hanger 30. The liner hanger
would
then be set by conventional methods. A sealing device known as a packer 38 can
then be operated to seal the upper end 40 of the liner 28 (i.e. that which is
further
uphole towards the surface). The liner 28 is run into the extended portion 22
of the
well by means of the tubing string 10 which, in the illustrated embodiment, is
a
liner running string 10. The running string 10 also provides a pathway for the
passage of cement into the liner 28 to seal the annulus 32, and for actuating
the
liner hanger 30 and packer 38.
[0073] The apparatus 12 of the present invention is incorporated into the
string 10, and so run into the wellbore 14 with the liner 28. As will be
described
below, the apparatus 12 serves for sending data relating to one or more
downhole
parameter to surface real-time, to facilitate completion of the well (by
installing the
liner 28), and preparation of the well for production. In the illustrated
embodiment,
the data which is recovered to surface relates to the orientation of a window
41 in
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the liner 28, through which a lateral wellbore (not shown) is to be drilled,
extending
from the main wellbore 14. As will be understood by persons skilled in the
art, data
relating to the orientation of the wellbore 14, and indeed other parameters,
is vital
to ensuring correct drilling and completion of the well shown, for accessing a
subterranean formation containing well fluids (oil and/or gas).
[0074] To this end and as shown in the enlarged perspective view of Fig. 2
and the longitudinal cross-sectional view of Fig. 3, the apparatus 12 also
carries a
sensor acquisition system 42 which is provided in an operating unit 44 of the
apparatus. The apparatus may include orientation sensors associated with the
acquisition system 42, for measuring directional positioning information, and
may
include suitable strain sensors (not shown) of known types, for measuring the
compressive load on the casing 28 having the window 41. As will be described
below, the sensors are provided in the sensor acquisition system 42, but may
be
separate and mounted in an elongate, generally tubular housing 46 of the
apparatus 12. The operating unit 44 includes suitable electronics which stores
the
data, relays the data to the transmitting device 50, and provides power for
operation of the apparatus 12. In this way, the data measured by the sensors
in
the system 42 can be transmitted to surface via the apparatus 12. As will be
described below, separate sensors may be provided and coupled to the apparatus
12, for transmitting data relating to various downhole parameters to surface.
The
sensors may be provided in separate components in the string 10 and coupled to
the apparatus 12. The apparatus 12 including the sensor forms a downhole data
acquisition and telemetry system according to the invention.
[0075] Parts of the apparatus 12 are also shown in the highly schematic
view of Fig. 4. The apparatus 12 is also shown in more detail in the
longitudinal
sectional view of Fig. 5, and the enlarged views of Figs. 6 and 7. The
apparatus 12
comprises the tubular housing 46, which defines an internal fluid flow passage
or
bore 48. A pulse generating device 50 is mounted in the housing 46, and serves
for controlling the flow of fluid along a flow path 52 which communicates with
the
internal fluid flow passage 48, to generate a fluid pressure pulse.
[0076] In the embodiment of the invention shown in Figs. 2 and 3, the
tubular housing 46 has a housing wall 60, an internal surface 61 and an
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surface 63. A space 65 is provided in the wall 60 of the housing 46, and takes
the
form of an aperture which extends between the internal surface 61 and the
external
surface 63, and opens on to the internal passage 48. The aperture 65 has
internal
and external openings which communicate with one another, and which are of
similar dimensions. The pulse generating device 50 is mounted in the aperture
65
for movement between a retracted position and a radially extended position.
The
device 50 is shown in the retracted position in solid outline in Fig. 3, and
in the
extended position in broken outline. Fig. 5 also shows the device 50 in the
extended position. In the extended position, part of the device 50 extends
beyond
the external surface 63 of the housing. In particular, an external surface 51
of the
device 50 is located beyond the housing surface 63.
[0077] Mounting the pulse generating device 50 for movement between
such retracted and extended positions provides the advantage that a maximum
width dimension (in particular a diameter) described by the apparatus 12 can
be
arranged to be less when the device 50 is in the retracted position,
facilitating
deployment of the apparatus 12 along the wellbore 14 to a desired placement
point. This may in particular facilitate passage of the apparatus 12 through
or past
a restriction in the casing 18 (such as upsets or profiles in the casing 18).
This may
provide the advantage that it is not necessary to make the wellbore 14 larger
than
might otherwise be the case, to accommodate the apparatus 12. It is of note
that
it is not uncommon for a wellbore to be enlarged using an underreamer to allow
passage of larger tubulars. There may also be a restriction or a restricted
bore that
the tool needs to pass through such that it can be placed in a hole location
that has
been enlarged/underreamed, or left conventionally sized consistent with that
required to run the original casing into.
[0078] In the illustrated embodiment, the placement point for the device
50 is determined by the required position for the liner 28, as shown in Fig.
1, the
apparatus 12 carrying the device 50 being located downhole of the window 41 in
the liner. Following location at the desired placement point, the device 50
can be
moved to the radially extended position. Advantageously therefore, the
invention
provides the ability to open up access through the tubular housing 46 (and so
through the apparatus 12) when the device 50 is in the extended position. This
can
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be appreciated from Fig. 1, which shows the device 50 in the retracted
position,
where it impedes the internal passage 48 of the tubular housing 46.
Optionally, the
apparatus 12 may be located in a portion of a wellbore which has been
underreamed, to provide sufficient clearance for movement of the device 50 to
the
extended position. This is shown in Fig. 9, where the extended portion 22 of
the
wellbore has been underreamed, as shown at 23 in the drawing.
[0079] Typically, the retracted position will be an operating position of the
device 50, in which the device is employed to generate fluid pressure pulses
representative of at least one parameter measured downhole in the well. The
device 50 is moved to the extended position following operation to generate
fluid
pressure pulses to send data to surface. However, it will be understood that
the
device 50 may be equally be capable of generating fluid pressure pulses when
in
the extended position. Indeed, an operating position of the device 50 may be
the
extended position, rather than the retracted position.
[0080] In the retracted position, the pulse generating device 50 does not
extend beyond the external surface 63 of the tubular housing 46. The device 50
is
therefore retracted into the aperture 65, and does not protrude beyond the
external
surface out of the aperture. This facilitates passage of the apparatus 12
along the
wellbore 14, navigating past any restrictions in the wellbore. In the
retracted
position, the pulse generating device 50 extends beyond the internal surface
61 of
the tubular housing 46 and into the internal fluid flow passage 48. In the
extended
position, the device 50 does not extend beyond the internal surface 61, and so
does
not extend into the internal fluid flow passage 48. This may provide the
ability to
open full bore access through the tubular housing 46 when the device 50 is in
the
extended position. This may be particularly desirable in order to allow
subsequent
deployment of tools/equipment into the wellbore downhole of the apparatus 12,
and in terms of maximizing fluid flow through the apparatus.
[0081] The apparatus 12 also comprises a mounting member, which takes
the form of a mounting block 67, which receives the device 50. The mounting
block
67 is mounted for movement between the retracted and extended positions,
carrying the device 50, and so serves for moving the device between said
positions.
The pulse generating device 50 is mounted in the block 67 in such a way that,
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when the block is moved to an extended position, at least part of the device
50
protrudes beyond the external surface 63 of the housing 46.
[0082] Effectively, the mounting block 67 forms a floating mounting block
or piston which is mounted in the aperture 65, and which is sealed relative to
the
wall 60 via suitable seals 71. The aperture 65 thereby effectively defines a
cylinder
in which the mounting block 67 is mounted for movement between the retracted
and extended positions, under applied fluid pressure, which will be discussed
below.
A flange or stop 83 can be provided on the mounting block 67 for restricting
outward movement of the block. Following the teachings of WO-2011/004180, the
disclosure of which is incorporated herein by way of reference, the pulse
generating
device 50 takes the form of a cartridge which is releasably mounted in the
mounting block 67. The operation of the device 50 will be discussed in more
detail
below.
[0083] The device 50 is initially restrained in the retracted position, by at
least one latch element. In the illustrated embodiment, there are two such
latch
elements, one of which is shown (Fig. 3) and given the reference numeral 73.
The
latch element 73 takes the form of a dog or pin, and is actuable to release
the
device 50 for movement to the extended position. The dogs 73 are movable
between engaging positions, where they restrain the device 50, and a release
position, where the device 50 is released for movement to the extended
position.
The dogs 73 are arranged to engage the mounting block 67 to thereby restrain
the
device 50.
[0084] The apparatus 12 is also arranged so that the device 50 can be
restrained in the extended position, again by means of at least one latch
element.
In the illustrated embodiment, there are two such latch elements, one of which
is
shown and indicated by reference numeral 75. The latch element 75 takes the
form
of a dog or pin, and is actuable to engage the device 50. The dogs 75 are
movable
between a release position, so that movement of the device 50 to the extended
position is permitted, and an engaging position where they restrain the device
50 in
the extended position. The dogs 75 may be shearable or breakable to permit
release of the device 50, for movement from the extended position back to the
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retracted position. Again, the dogs 75 are arranged to engage the mounting
block
67 to thereby restrain the device 50.
[0085] Actuation options for the dogs 73 and 75 include mechanical,
electrical, electromechanical, hydraulic and combinations thereof.
[0086] As mentioned above, the device 50 is movable from its retracted
position to its extended position under applied fluid pressure. This is
achieved by
creating a pressure differential between fluid in the internal fluid flow
passage 48
relative to fluid externally of the tubular housing 46, in the annulus 32. For
example, the pressure of the fluid in the internal passage 48 may be raised
using a
pump at surface, so that the fluid pressure force acting on an internal piston
face
defined by the mounting block 67 is greater than that acting on an external
piston
face (that resulting from the pressure of fluid in the annulus 32). However,
the
device 50 may be movable from the retracted position to the extended position
via
application of a mechanical force, such as by passing an expansion tool or
element
(not shown) through the internal fluid flow passage 48, the tool imparting a
force
on the device to urge it to the extended position. The device 50 is similarly
movable from the extended position back to the retracted position by applied
fluid
pressure, in this case by raising the pressure in the annulus 32, or by
allowing the
pressure of the fluid in the passage 48 to fall.
[0087] The tubular housing 46 defines an external upset 77 which forms or
defines part of the external surface 63 of the housing 46. The tubular housing
46
may, however, be arranged to define an internal upset which forms at least
part of
the internal surface 61 of the housing 46, and so which may protrude into the
internal passage 48 to some extent.
[0088] Optionally, the apparatus 12 can comprise a plurality of pulse
generating devices, and Fig. 4 illustrates an option where the apparatus 12
comprises the device 50, plus a second similar such device 54. Both of the
devices
50 and 54 are mounted in the mounting block 67, and so movable between
retracted and extended positions in unison. The devices 50 and 54 can be
operated
in various different ways, and can, for example, be employed to issue separate
or
combined pressure pulse signals. In a further variation, the apparatus 12 may
comprise only a single pulse generating device 50, and associated
operating/power
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and sensor equipment may be arranged differently from that described above.
For
example and referring to Fig. 4, a battery or other power source for operating
the
pulser 50 may be provided in the location indicated by the numeral 54; the
sensor
assembly 42 may be provided in the location indicated by the numeral 54; or
the
operating unit 44 may be provided in the location indicated by the numeral 54.
[0089] Operation of the devices 50 and 54 is achieved in a similar fashion,
and will now be described.
[0090] The operating unit 44 is arranged to operate the device 50, or both
the first and second devices 50 and 54 where provided, simultaneously or
individually, as required. The operating unit 44 is shown in more detail in
Fig. 8,
which is a further enlarged perspective view of part of the apparatus shown in
Fig.
5, with certain internal components shown in ghost outline and showing the
operating unit during insertion into the mounting block 67. The operating unit
44
includes an electronics section 66 which comprises the sensor acquisition
system
42, first and second electrical power sources in the form of batteries 69a and
69b,
first and second electrical connector elements 68a, 68b and a suitable data
storage
device (not shown). The batteries 69a and 69b provide power for actuation of
the
devices 42, 50 and 54, respectively, although a single battery may be
utilized. The
connector elements 68a, 68b provide electrical connection with the devices 50
and
54 so that they can be operated to transmit data relating to parameters
measured
by the sensors in or associated with the sensor acquisition system 42 to
surface.
[0091] The first and second devices 50 and 54 each comprise a valve, one
of which is shown and given the reference numeral 74. The valves 74 comprise a
valve element 76 and a valve seat 78, the valves being actuable to control the
flow
of fluid along the respective flow paths 52. This is achieved by moving the
respective valve elements 76 into or out of sealing abutment with the valve
seats
78. The devices 50 and 54 also each include respective actuators 70 coupled to
the
valve elements 76, to thereby control the flow of fluid through the respective
flow
paths 52. The actuators 70 are electrically operated, and take the form of
solenoids or motors having shaft linkages 81. The actuator shaft linkages 81
are
coupled to the valve elements 76 to control their movement, and provide linear
or
CA 02914295 2016-11-30
rotary inputs for operation of the valve elements, the latter being via a
suitable rotary to linear
converter.
[0092] Power for operation of the actuators 70 is provided by the battery
packs 69a,
69b via the connector elements 68a, 68b. As shown in Figs. 6 and 8, the
connector elements
68 are located within seal bore assemblies 90 mounted within bores 92 of the
devices 50, 54.
Ends 98 of the connector elements 68a, 68b make electrical connection with
sockets 99,
which transmit power to the actuators 70. Operation of the actuators 70 causes
the actuator
shaft linkage 81 to translate the valve elements 76 out of sealing engagement
with the valve
seat 78. When it is desired to return the valves 74 to their closed positions,
the actuators 70
are deactivated and return springs (not shown) urge the valve elements 76 back
into sealing
abutment with their valve seats 78.
[0093] The structure and operation of both the valves 74 and actuators 66 are
in most
respects similar to that disclosed in WO-2011/004180. Accordingly, these
components will
not be described in further detail herein.
[0094] The first and second devices 50 and 54 are mounted in respective spaces
80
and 82 provided in the floating mounting block 67. The operating unit 44 is
similarly
mounted in a space 84 in the mounting block 67, which is separate from the
spaces 80, 82 in
which the first and second devices 50, 54 are mounted but which opens on to
them. As
shown, the devices 50, 54 and the operating unit 44 are mounted entirely
within the
respective spaces 80, 82 and 84.
[0095] The first and second devices 50, 54 and indeed the operating unit 44
are in the
form of cartridges or inserts which can be releasably mounted in the mounting
block 67, in
the spaces 80, 82 and 84. Whilst shown as pockets or recesses, the spaces 80,
82 and/or 84
could take the form of bored chambers in the mounting block 67.
[0096] The cartridges of the first and second devices 50, 54 and operating
unit 44 are
shaped so that they are entirely mounted within the respective spaces 80, 82
and 84. The
cartridges of the first and second devices 50, 54 house the respective valves
74. The first and
second devices 50 and 54 also define part of the respective flow paths 52, the
flow paths
extending from the inlets 58 in the
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housing wall 60, through the valves 74 to outlets 62. Operation of the valves
74
thereby controls the flow of fluid along the flow paths 52 from the inlets 58
to the
respective outlets 62 to generate pulses. Positive or negative fluid pressure
pulses
may be generated by the devices 50, 54. Positive pulses are generated by
operating the devices 50, 54 to close the respective flow paths 52, 56, and
negative
pulses by operating the devices to open the flow paths.
[0097] Turning now to Fig. 10, there is shown a sectional view through
part of an apparatus for generating a fluid pressure pulse downhole in
accordance
with another embodiment of the present invention, the apparatus indicated by
reference numeral 12'. Like components of the apparatus 12' with the apparatus
12 of Figs. 1 to 9 share the same reference numerals, with the addition of the
suffix
,.
[0098] The apparatus 12' is of similar construction to the apparatus 12,
and only the significant differences will be described herein. The apparatus
12' is
shown in Fig. 10 sectioned transverse to a main longitudinal axis of a housing
46' in
the region of a device 50' for generating a fluid pressure pulse. The device
50' is
shown in Fig. 10 in a retracted position. Fig. 11 is a further enlarged view
of part of
the apparatus 12', in particular of part of a wall 60' of the housing 46'.
Fig. 12 is a
view of the apparatus 12' with the device 50' in a radially extended position.
[0099] In this embodiment, the device 50' is mounted in a space 65' in the
wall 60' which takes the form of a recess or pocket. The device 50' is mounted
in
the space 65' in such a way that movement of the device within the space is
restricted. The apparatus 12' is, in this embodiment, configured so that the
device
50' is movable from the retracted position to the radially extended position
by
imparting an expansion force on the tubular housing 46', in particular on the
part
which defines the space 65'. The tubular housing 46' is therefore configured
so that
it is expandable to permit movement of the device 50' to the extended
position. In
this embodiment, the device 50' forms part of an external surface 63' of the
housing 46', or is located in a portion of the housing 46' which defines part
of the
external surface 63', and which surface part is moved radially outwardly when
the
device 50' is moved to the extended position.
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[00100] In the illustrated embodiment, the tubular housing 46' comprises a
plurality of deformation zones 102, which are configured to deform so that the
device 50' can move to the extended position. The deformation zones 102 are
provided between a part 104 of the tubular housing 46' which defines the space
65', and a main part 106 of the housing 46'. The space 65' is elongate in a
direction along a longitudinal axis of the housing 46', and the zones 102
border the
lateral sides of the space, extending in a direction along the longitudinal
axis.
Effectively however, there are zones of deformation bordering the space 65'
around
its entire perimeter, although only two are shown in the drawings. Any
suitable
number of deformation zones may be provided to permit the desired movement of
the device 50'.
[00101] The deformation zones 102 are regions of the tubular housing 46'
which are shaped so as to permit the required radially outward movement of the
device 50' to its extended position. In the illustrated embodiment, the
tubular
housing 46' is shaped to define at least one corrugation or fold 108 in the
deformation zones 102, the corrugations arranged so that they can be at least
partially opened out or extended on exertion of an expansion force, so that
the
device can move to the extended position. This is shown in Fig. 12.
[00102] The deformation zones 102 comprise a material having at least one
material property which differs from a corresponding property of a majority of
the
housing, and in particular from the part 104 of the housing defining the space
65'.
The material property is typically the yield strength, and the deformation
zones 102
comprise a portion 112 of a material having a lower yield strength than the
remainder of the housing 46'. This may encourage the tubular housing 46' to
deform in the deformation zones 102, on application of an expansion force. By
way
of example, a majority of the housing 46' (in particular the main part 106 and
the
part 104 defining the space 65') may be of a steel alloy having a higher yield
strength than that of the portion 112, so that deformation occurs in the
portion
102, which includes the corrugation 108. Deformation may be achieved by
applied
fluid pressure or mechanical expansion, such as using an expansion tool,
following
the techniques described above. For example and as shown in Fig. 10, hydraulic
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rams 110 may be actuated to impart a force on the portion 104 defining the
space
65'.
[00103] Whilst the apparatus of the present invention has been shown and
described in the transmission of data to surface relating to compressive load
applied to a wellbore-lining tubing, it will be understood that the apparatus
has a
wide range of uses including in the drilling and production phases, or indeed
in an
intervention operation (e.g. to perform remedial operations in the well
following
commencement of production). Accordingly, the apparatus may have a use in
transmitting data relating to other parameters pertinent to the drilling,
completion
or production phases and/or in an intervention. Such may include but are not
limited to pressure (e.g. in the internal bore and/or externally of the
tubular
housing); temperature; geological features (e.g. rock resistivity, background
radiation); density; force (e.g. an axially directed force such as a weight
applied to
a component in the wellbore, which might be weight on bit (WOB), or a
rotationally
directed force or torque applied to a component in the wellbore, which might
be
torque on bit (TOB) or in wellbore tubing); strain; stress; acceleration; and
wellbore geometry features (e.g. rotational orientation or 'azimuth',
inclination, the
depth of a particular component or feature).
Sensors appropriate for the
measurement of the required parameter(s) may be provided.
[00104] Various modifications may be made to the foregoing without
departing from the spirit or scope of the present invention.
[00105] In the retracted position, the device may extend a first distance
beyond the external surface of the tubular housing; and in the extended
position,
the device may extend a second distance beyond the external surface of the
tubular
housing which is greater than said first distance.
[00106] In the retracted position, the device may extend a first distance
beyond the internal surface of the tubular housing and into the internal fluid
flow
passage; and in the extended position, the device may extend a second distance
beyond the internal surface of the tubular housing and into the internal fluid
flow
passage, said second distance being smaller than said first distance.
[00107] The device may comprise or may take the form of a cartridge which
can be releasably movably mounted in the aperture.
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[00108] Said latch element may be shearable or breakable to release the
device for movement to the extended position.
[00109] The latch elements may be provided in the tubular housing, in the
device (such as in the mounting member), or optionally in both the housing and
the
device.
[00110] The device may be movable from the extended position to the
retracted position via application of mechanical force, such as via contact
between
the device and a feature in the wellbore. The feature may be a dedicated
feature,
such as an upset or profile, provided in the wellbore for imparting a force on
the
device.
[00111] The apparatus may comprise a plurality of devices for generating a
fluid pressure pulse. Each device may be located in a respective aperture. A
plurality of devices may be located in one aperture.
Where the apparatus
comprises a mounting member, the mounting member may receive a plurality of
pulse generating devices.
[00112] The aperture openings may be of different dimensions, profile
and/or shape.
[00113] The apparatus may be arranged to automatically restrain the
device in the extended position following movement to said position. For
example,
the latch element may be sprung or otherwise biased.
