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Claims  |
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I claim:
1. Propulsion apparatus for attachment to a selected tool for propelling
and positioning the tool in a tubular member in response to fluid pressure
exerted within the tubular member, comprising:
a top sub portion adapted for connection to the mating end of the tool,
an elongated tubular mandrel depending from said top sub portion and
terminating in a lower free end,
a tubular sleeve concentrically disposed around said elongated tubular
mandrel and adapted for coaxial sliding movement with respect thereto,
cup apparatus mounted on said sleeve and having at least one fin element
projecting radially and circumferentially therefrom for substantially
reducing all of the annular space between said sleeve and the inner
surface of the tubular member and cooperating with said sleeve and the
tubular member and fluid pressure exerted therein for translating fluid
differential pressure developed across said at least one fin element of
said cup apparatus into propelling forces having a preselected magnitude
and cooperating therewith to apply said forces to said sleeve,
sleeve retaining means cooperating with said sleeve and mandrel for
positioning and retaining said sleeve in a first position with respect to
said mandrel and cooperating with said propelling forces having said
preselected magnitude and with said cup apparatus for transmitting said
propelling forces cooperating with said cup apparatus and sleeve to said
mandrel and the attached tool for propelling and positioning the tool to a
selected location within the tubular member,
wherein said cup apparatus and sleeve retaining means cooperatively respond
to a preselected change in the fluid pressure differential acting across
said cup apparatus for releasing said sleeve and permitting predetermined
movement thereof from said first position with respect to said mandrel,
said predetermined movement of said sleeve with respect to said mandrel
allowing substantial equalization of the differential pressure developed
across said cop apparatus.
2. The propulsion apparatus as described in claim 1, wherein said tubular
mandrel further includes an inner axial bore disposed through at least a
portion of the lower length thereof and communicating with said mandrel
free end and a port transversely disposed through said tubular mandrel and
spaced from said free end thereof for communicating with said inner axial
bore.
3. The propulsion apparatus as described in claim 2, wherein said sleeve
positioning means comprises a plurality of shear pins having a preselected
shearing resistance exceeding said propelling forces first magnitude and
radially disposed through registering circumferentially spaced apertures
disposed in said tubular mandrel and sleeve for positioning and retaining
said sleeve in said preselected position with respect to said mandrel and
closing said transverse port disposed in said mandrel for substantially
prohibiting fluid communication therethrough.
4. The propulsion apparatus as described in claim 3, wherein said
preselected change in the fluid pressure differential acting across said
cup assembly sleeve increases the propelling forces transmitted to said
sleeve and said plurality of shear pins to exceed the shearing resistance
thereof for releasing said sleeve for coaxial movement from said
preselected position on said tubular mandrel and opening said mandrel
transverse port for diverting fluid above said cup assembly through said
mandrel transverse port and axial bore.
5. The propulsion apparatus as described in claim 2, wherein said sleeve
positioning means comprises:
a shear ring coaxially disposed about the outer diameter of said tubular
mandrel and attached to said sleeve, and
a plurality of shear pins having a preselected shearing resistance
exceeding said propelling forces first magnitude and circumferentially
spaced and radially disposed in said tubular mandrel for engaging and
supporting said shear ring and sleeve in said preselected position with
respect to said mandrel and closing said transverse port disposed in said
mandrel for substantially prohibiting fluid communication therethrough.
6. The propulsion apparatus as described in claim 5, wherein said
preselected change in the fluid pressure differential acting across said
cup assembly increases the propelling forces transmitted to said sleeve,
shear ring and said plurality of shear pins to exceed the shearing
resistance thereof for releasing said sleeve for coaxial movement from
said preselected position on said tubular mandrel and opening said mandrel
transverse port for diverting fluid above said cup assembly through said
mandrel transverse port and axial bore.
7. The propulsion apparatus as described in claims 4 or 6, wherein said
tubular mandrel includes a circumferential shoulder spaced from said free
end for engaging and limiting the coaxial movement of said sleeve with
respect to said tubular mandrel after said sleeve has opened said mandrel
transverse port for fluid communication.
8. The propulsion apparatus as described in claim 2, wherein said sleeve
positioning means comprises biasing means cooperating with said sleeve and
tubular mandrel for exerting preselected biasing forces exceeding said
fluid propelling forces acting on said cup assembly to position said
sleeve with respect to said mandrel in said preselected position and
closing said transverse port disposed in said mandrel for substantially
prohibiting fluid communication therethrough.
9. The propulsion apparatus as described in claim 8, wherein said
preselected change in the fluid pressure differential acting across said
cup assembly sleeve increases the propelling forces transmitted to said
sleeve for overcoming said preselected biasing force exerted by said
biasing means and permitting coaxial movement of said sleeve from said
preselected position with respect to said tubular mandrel and opening said
mandrel transverse port for diverting fluid above said cup assembly
through said mandrel transverse port and axial bore.
10. The propulsion apparatus as described in claim 9, wherein said biasing
means comprises a compression spring adapted to engage said mandrel and
said sleeve for applying preselected biasing forces to said sleeve.
11. The propulsion apparatus as described in claim 9, wherein said selected
change in the fluid pressure differential acting on said cup assembly is
introduced by increasing the pressure of the fluid pumped into the tubular
member for increasing the differential pressure across said cup assembly
and transmitted to said sleeve for exceeding said preselected biasing
forces exerted by said biasing means.
12. The propulsion apparatus as described in claims 4 or 6 or 9, wherein
said downhole tubular member includes a closed lower end with an axial
bore therethrough, and wherein said apparatus further includes coupling
means cooperating with said closed lower end of said tubular member and
said axial bore and said lower free end of said mandrel for permitting
latching engagement therebetween and permitting fluid communication
between fluid in the tubular member above said cup assembly through said
mandrel transverse port and mandrel axial bore and said closed end axial
bore.
13. The propulsion apparatus as described in claim 12, wherein said mandrel
lower free end includes a probe element projecting coaxially therefrom and
having an axial bore therethrough for permitting fluid communication
therethrough from said mandrel coaxial bore, and wherein said coupling
means comprises engaging means disposed in the closed end of the downhole
tubular member and cooperating with said mandrel probe element and said
axial bore through said tubular member closed end for engaging and
latching said probe element with respect to said tubular member closed end
and permitting fluid communication through said mandrel transverse port
and mandrel axial bore and said tubular member closed end axial bore.
14. The propulsion apparatus as described in claim 13, wherein said
engaging means comprises:
a guide member mounted on said tubular member closed lower end for
contacting said probe element and guiding said probe element into proper
compass orientation therewith and into fluid communication with said axial
bore in said tubular member closed end, and
latching means cooperating with said tubular member closed end and said
mandrel probe element for engaging said probe element and removably
latching said probe element to said tubular member closed end in fluid
communication with said axial bore therethrough.
15. The propulsion apparatus as described in claim 1, wherein said sleeve
positioning means comprises a plurality of shear pins having a preselected
shearing resistance exceeding said propelling force preselected magnitude
and radially disposed through registering circumferentially spaced
apertures disposed in said tubular mandrel and sleeve for positioning and
retaining said sleeve in said preselected position with respect to said
mandrel.
16. The propulsion apparatus as described in claim 15, wherein said
preselected change in the fluid pressure differential acting across said
cup assembly increases the propelling forces transmitted to said sleeve
and said plurality of shear pins for exceeding the shearing resistance
thereof and releasing said sleeve from said preselected position on said
tubular mandrel for coaxial movement with respect thereto and
disengagement from said mandrel lower free end.
17. The propulsion apparatus as described in claim 1, wherein said sleeve
positioning means comprises:
a shear ring coaxially disposed about the outer diameter of said tubular
mandrel and attached to said sleeve, and
a plurality of shear pins having a preselected shearing resistance
exceeding said propelling force preselected magnitude and
circumferentially spaced and radially disposed in said tubular mandrel for
engaging and supporting said shear ring and sleeve in said preselected
position with respect to said mandrel.
18. The propulsion apparatus as described in claim 17, wherein said
preselected change in the fluid pressure differential acting across said
cup assembly increases the propelling forces transmitted to said sleeve,
shear ring and said plurality of shear pins for exceeding the shearing
resistance thereof and releasing said sleeve from said preselected
position on said tubular mandrel for coaxial movement with respect thereto
and disengagement from said mandrel lower free end.
19. The propulsion apparatus as described in claims 4 or 6 or 16 or 18,
wherein said selected change in the fluid pressure differential acting on
said cup assembly is introduced by pumping pressurized fluid into the
tubular member above said cup assembly for creating a differential
overpressure across said cup assembly and transmitted to said sleeve and
plurality of shear pins sufficient to exceed the shearing resistance
thereof.
20. The propulsion apparatus as described in claims 4 or 6 or 16 or 18,
wherein said selected change in the fluid pressure differential acting on
said cup assembly is introduced by raising the tool and attached
propulsion apparatus through the fluid in the tubular member at a speed
sufficient to create a differential overpressure across said cup assembly
and transmitted to said sleeve and plurality of shear pins sufficient to
exceed the shearing resistance thereof.
21. A method of propelling and positioning a selected tool in a tubular
member in response to fluid pressure exerted within the tubular member,
comprising the steps of:
attaching propulsion apparatus to the lower mating end of the downhole
tool, said propulsion apparatus comprising:
a top sub portion adapted for connection to the mating end of the selected
tool,
an elongated tubular mandrel depending from said top sub portion and
terminating in a lower free end,
a tubular sleeve concentrically disposed around said elongated tubular
mandrel and adapted for coaxial sliding movement with respect thereto,
cup apparatus mounted on said sleeve and having at least one fin element
projecting radially and circumferentially therefrom for substantially
reducing all of the annular space between said sleeve and the inner
surface of the tubular member and cooperating with said sleeve and the
tubular member and fluid pressure exerted therein for translating fluid
pressure developed in the tubular member into forces cooperating with said
cup apparatus and acting as a propelling force applied to said sleeve, and
sleeve retaining means cooperating with said sleeve and mandrel for
positioning and retaining said sleeve in a first position with respect to
said mandrel and cooperating with said fluid pressure for transmitting
said fluid pressure forces cooperating with said cup apparatus and sleeve
to said mandrel and the attached tool,
increasing the pressure of the fluid in the tubular member above said cup
apparatus for creating a fluid differential pressure thereacross that
translates into coaxial propelling forces acting thereon,
positioning the propulsion apparatus and attached tool to a desired
position in the tubular member in response to said coaxial propelling
forces acting on said cup apparatus, and
creating a selected change in the fluid pressure differential across said
cup apparatus for cooperating therewith and with said retaining means for
releasing said sleeve from said mandrel and permitting predetermined
coaxial sliding movement therebetween from said first position with
respect to said mandrel, said predetermined movement of said sleeve with
respect to said mandrel allowing substantial equalization of the
differential pressure across said cup apparatus. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
The present invention relates to hydraulically-actuated propulsion devices
and more particularly to a propulsion apparatus for use with selected
tools to permit insertion and positioning of the tools into borehole
tubular members, including well casing and tubing, tubular drill string
members or pipeline sections in response to fluid pressure acting on the
propulsion apparatus.
Wireline logging and well completion tools are inserted into typical
vertical or slightly deviated oil and gas boreholes by gravitational
action on the end of a cable (the "wireline") spooled from a drum and
winch arrangement on the surface. The wireline tool is lowered into the
borehole to a desired depth location and then is raised at a preselected
rate during logging operations, or raised or lowered to accomplish other
operations. However, in highly deviated or horizontal boreholes, the
wireline tool and wireline cable will engage the sides of the borehole
walls and the friction between the assembly and the borehole walls
prevents continued movement into the borehole.
Similarly, pipeline inspection tools in above-ground or buried pipelines
must be "pushed" or "pulled" through the pipeline in order to traverse the
length to be inspected. In large diameter pipelines, fluid pressure or air
pressure actuated "pigs" or locomotives pull the measurement instruments
through the pipeline length to be investigated. In many cases, it is often
necessary to have access to each end of the pipeline section to be
investigated in order to provide cable systems for pulling the tool
through the pipeline section. In extremely long pipeline sections, it
would be advantageous to be able to propel and position the inspection
tools from one accessible end and then recover the tool from the same end.
Another tool positioning problem in downhole tubular members occurs in
drilling deviated wellbores ("directional drilling") using drilling fluid
driven drilling motors ("mud motors") that turn the rotary drilling bit on
the end of the drill string instead of the entire drill string being
driven by a rotary turntable located on the drilling rig. The mud motor is
driven by drilling fluid transported downhole through the drill string,
i.e., tubular members such as drill pipe and drill collars which make up
the drill string. A "steering" tool which controls the direction of
drilling of the mud motor is positioned just above the mud motor within
the drill string and generally must be properly "aligned" with respect to
the mud motor. The steering tool is generally positioned downhole using a
wireline cable, which is an expensive and time consuming operation.
However, when a well deviation exceeds .+-.50.degree., the positioning of
the steering tool can no longer be accomplished by gravity powered methods
such as using a wireline cable. Further, it has been difficult to properly
"align" the steering tool with the mud motor for a known azimuth
direction, and ideally, the mud motor is not operational while the
steering tool is being properly positioned.
Accordingly, previously in highly deviated and horizontal oil and gas wells
(which are increasing in popularity due to many technological and
production advantages over vertical boreholes) wireline tools were not
usable and the well logging and completion tools had to be "pushed" or
"oonveyed" into the deviated or horizontal borehole by means of tubing
strings or flexible coiled tubing pushed down into the borehole.
Similarly, in pipelines, certain inspection tools that are available by
wireline could not be used unless "pushed" or "pulled" into the pipeline
using tubing or by cable if both ends of the pipeline were accessible and
the length was not too great. Such tubing conveyed systems are much more
expensive to operate than a conventional wireline tool, because of the
expense of the great lengths of tubing necessary to insert the tool and
because of the expense and complexity of the means necessary to drive the
tubing string into the deviated or horizontal borehole or pipeline section
and to later retrieve the tubing string.
Accordingly, one feature of the present invention is to provide propulsion
apparatus that is fluid actuated for conveying and positioning selected
conventional tools in tubular members, especially those that are highly
deviated or horizontal.
Another feature of the present invention is to provide a propulsion
apparatus that, once hydraulically positioned in the tubular member,
responds to a selected fluid pressure change for actuating the propulsion
apparatus to allow equalization of the hydraulic pressure acting on the
propulsion apparatus.
Still another feature of the present invention is to provide a fluid
actuated propulsion apparatus embodiment for conveying and positioning a
selected tool within a tubular drill string and permitting fluid above the
propulsion apparatus to be discharged through a closed end of the tubular
drill string.
SUMMARY OF THE INVENTION
In accordance with a primary principle of the present invention, a
propulsion apparatus is provided for attachment to a selected tool for
propelling and positioning the tool in a tubular member in response to
fluid pressure in the tubular member that includes a top sub portion
adapted for connection to the mating end of the tool, an elongated tubular
mandrel depending from the top sub portion and terminating in a lower free
end, and a tubular sleeve concentrically disposed around the elongated
tubular mandrel and adapted for coaxial sliding movement with respect to
the mandrel.
Piston means cooperates with the sleeve and the tubular member and fluid
pressure exerted therein for translating fluid differential pressure
developed across the piston means into preselected forces cooperating with
the piston means for applying propelling forces to the sleeve, and sleeve
positioning means is provided for cooperating with the sleeve and mandrel
and with the propelling force cooperating with the piston means for
positioning and retaining the sleeve in a first selected position with
respect to the mandrel and transmitting the propelling force cooperating
with the piston means and sleeve to the mandrel and the attached tool for
propelling and positioning the tool to selected locations within the
tubular member. The piston means and sleeve positioning means also
cooperate to respond to a preselected change in the fluid pressure
differential acting across the piston means for releasing the sleeve from
the first selected position with respect to the mandrel and permitting
coaxial movement therebetween to substantially equalize the differential
pressure developed across the piston means.
The piston means above described can comprise a cup assembly attached to
the tubular sleeve and having at least one fin element projecting radially
and circumferentially for reducing substantially the annular space between
the sleeve and the inner surface of the tubular member with the fluid
pressure differential created across the at least one fin element
generating the described propelling forces acting on the piston means.
In accordance with one principle of the invention, the tubular mandrel
further includes an inner axial bore disposed through at least a portion
of the lower length thereof and communicates with the mandrel free end has
a port transversely disposed through the mandrel for communicating with
the inner axial bore. Cooperating with the transverse ports in the mandrel
and the sleeve, the sleeve positioning means may include a plurality of
shear pins having a preselected shear resistance radially disposed and
circumferentially spaced around the mandrel and cooperating with the
sleeve to position and retain the sleeve in a position with respect to the
mandrel in which the transverse port disposed in the mandrel is closed for
substantially prohibiting fluid communication through the inner axial bore
of the mandrel.
In the embodiment above described, the transverse port in the mandrel is
opened to fluid communication as a result of a preselected change in the
fluid pressure differential acting across the cup assembly attached to the
sleeve and which increases the propelling forces acting on the cup
assembly and transmitted to the sleeve and shear pins that exceeds the
shearing resistance of the shear pins and releases the sleeve for coaxial
movement with respect to the mandrel for opening the mandrel's transverse
port and diverting the fluid above the cup assembly through the mandrel
transverse port and axial bore to equalize the differential pressure
across the cup assembly.
In accordance with another principle of the invention, the mandrel does not
contain an inner axial bore or a transverse port and the change in the
fluid pressure differential acting across the cup assembly attached to the
sleeve, and which increases the propelling forces acting on the cup
assembly and transmitted to the sleeve and shear pins, that exceeds the
shearing resistance of the shear pins releases the sleeve for coaxial
movement with respect to the mandrel and disengages from the lower end
thereof to equalize the differential pressure across the cup assembly.
In accordance with yet another principle of the invention, the sleeve
positioning means may comprise a compression spring acting as a biasing
means engaging the mandrel and the sleeve for biasing the sleeve to a
position with respect to the mandrel for closing the mandrel transverse
port for fluid communication through the mandrel. The differential
pressure developed across the cup assembly does not create sufficient
forces acting in opposition to the biasing forces of the compression
spring to overcome the spring biasing forces, yet provides sufficient
propelling forces to position the sleeve and mandrel in the tubular
member. However, when the change in the fluid pressure differential acting
across the cup assembly attached to the sleeve is increased, the forces
acting on the cup assembly overcome the biasing forces exerted by the
compression spring and allow the compression spring to move the sleeve to
a position with respect to the mandrel for opening the transverse port for
fluid communication therethrough.
In accordance with still another principle of the invention, the tubular
member comprises a tubular drill string which has a closed lower end with
an axial bore therethrough, and the apparatus further includes coupling
means cooperating with the closed lower end of the tubular member and the
closed end axial bore and the lower free end of the mandrel for permitting
latching engagement between the lower free end of the mandrel and the
closed end of the drill string and permitting fluid communication between
fluid in the drill string above the cup assembly through the mandrel
transverse port and axial bore and the drill string closed end axial bore.
The coupling means may also include a probe element projecting coaxially
from the lower free end of the mandrel and having an axial bore
therethrough, for permitting fluid communication from the mandrel axial
bore, and engaging means disposed in the closed end of the downhole drill
string cooperating with the probe element and the axial bore through the
drill string closed end for engaging and latching the probe element with
respect to the drill string closed end and permitting fluid communication
through the mandrel transverse port and axial bore and the drill string
closed end axial bore.
The engaging means may comprise a guide member mounted on the drill string
lower end for contacting the probe element attached to the lower end of
the mandrel and guiding the probe element into proper orientation for
fluid communication with the axial bore in the drill string closed end,
and latching means for engaging the probe element and removably latching
the probe element to the drill string closed end in fluid communication
with the axial bore disposed in the closed end.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the manner in which the above-recited principles and features
of the invention are attained can be understood in detail, a more
particular description of the invention may be had by reference to
specific embodiments thereof which are illustrated in the accompanying
drawings, which drawings form a part of this specification.
In the drawings:
FIG. 1 illustrates the propulsion apparatus according to this invention
attached to a selected tool for positioning the tool in a typical highly
deviated or horizontal wellbore.
FIG. 2 illustrates the propulsion apparatus according to this invention
attached to a selected tool for positioning the tool in a typical pipeline
segment.
FIG. 3A is a detailed side view, partly in cross-section, showing one
embodiment of the propulsion apparatus disposed in a tubular member with
the sleeve held by shear pins, closing the axial bore through the mandrel
to fluid communication.
FIG. 3B is a detailed side view, partly in cross-section, showing the
embodiment of the propulsion apparatus disclosed in FIG. 3A with the shear
pins having been sheared and the sleeve displaced on the mandrel to open
the axial bore through the mandrel to fluid communication.
FIG. 4A is a detailed side view, partly in cross-section, showing a
variation of the first embodiment of the propulsion apparatus disposed in
a tubular member with the sleeve and a shear ring held by shear pins,
closing the axial bore through the mandrel to fluid communication.
FIG. 4B is a detailed side view, partly in cross-section, showing the
variation in the second embodiment of the propulsion apparatus disclosed
in FIG. 4A with the shear pins having been sheared and the sleeve and
shear ring displaced on the mandrel to open the axial bore through the
mandrel to fluid communication.
FIG. 5 is a detailed side view, partly in cross-section, showing a second
embodiment of the propulsion apparatus disposed in a tubular member with
the sleeve held in place with regard to the mandrel by shear pins, and
with the sleeve shown disengaged from the lower end of the mandrel by the
dotted lines.
FIG. 6 is a detailed side view, partly in cross-section, showing a
variation of the embodiment of the propulsion apparatus disposed in a
tubular member as shown in FIG. 5 with the sleeve and a shear ring
supported by shear pins.
FIG. 7A is a detailed side view, partly in cross-section, showing the third
embodiment of the propelling apparatus disclosed in FIG. 7A with the
sleeve displaced by the biasing forces of the compression spring exceeding
the fluid propelling forces acting thereon to close the mandrel transverse
port to fluid communication.
FIG. 7B is a detailed side view, partly in cross-section, showing a third
embodiment of the propulsion apparatus disposed in a tubular member with
the sleeve compressed against a counterbiasing compression spring under
the fluid propelling forces to open the mandrel transverse port to fluid
communication.
FIG. 8 is a view of a typical layout of a drilling rig showing a drill
string and drill bit for drilling a borehole in which another embodiment
of the propulsion apparatus may be utilized to propel a mud motor steering
tool into the drill string.
FIG. 9 is detailed side view, partly in cross-section, showing another
embodiment of the propulsion apparatus disposed in a tubular drill pipe or
drill collar section and attached to a mud motor steering tool for
latching to the last pipe section for communicating fluid to the mud
motor.
FIG. 10 is a horizontal cross-sectional view of the coupling means disposed
in the final tubular drill string member for latching the propulsion
apparatus in place, taken along lines 10-10 of FIG. 9.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 1, a deviated borehole 11 is shown drilled in earth
formation 12. A substantial portion of the borehole 11 has been set in
steel casing 10, which forms an elongated tubular member closed at the
earth's surface by a wellhead 24. The propulsion apparatus 14 according to
this invention is shown disposed in the borehole casing 10 and comprises a
top sub portion 34, an elongated tubular mandrel 30 having a free end 36,
a sleeve 40 and a piston means 32 cooperating with the sleeve 40 as will
hereinafter be further described. The top sub portion 34 is threadably and
removably connected to the downhole end of a selected tool 16 which is
maintained in substantial central axial alignment in the casing 16 by
means of conventional centralizers 15. The tool 16 may be a wireline
logging instrument or combination of logging instruments or other wireline
tools or perforating guns that define the selected tool package 16. The
wireline tool 16 and attached propulsion apparatus 14 are suspended in the
borehole casing 10 by means of a steel cable 18 (the "wireline") that acts
both as a support cable and provides for control and data signal
communication between the selected tool 16 and surface electronics and
recording apparatus disposed in the recording station truck 22. The cable
18 is supported by sheaves 20 and 21 and dispensed and taken up on a
conventional rotating drum (not shown) associated with the recording truck
22. The truck station 22 contains necessary electronic control,
transmitting and receiving equipment and display and recording equipment
for controlling and monitoring the operation of the tool or tool
combination 16 and the propulsion apparatus 14. The length of the cable
attached to the tool 16 and apparatus 14 (i.e., the depth of the tool
apparatus/ combination 11/14) is conventionally measured by the rotation
of the sheave 20 by means not shown. A fluid pump 26 is interconnected
through the wellhead 24 to the borehole casing 10 in a conventional manner
in order to pump pressurized fluid in the direction shown by arrows 17,
such as water or oil, into the tubular borehole casing 10 to provide a
fluid differential pressure acting across the piston means 32 that is
translated into fluid propelling forces acting coaxially on the piston
means to propel the propulsion apparatus and attached selected tool
downhole in a manner to be hereinafter further described.
FIG. 2 shows another application of the propulsion apparatus 14 as used in
a tubular section of a buried pipeline 10', although the application would
be identical in an above-ground pipeline situation. As shown, the
propulsion apparatus 14 is identical to that above described in FIG. 1,
comprising top sub portion 34, mandrel 30, sleeve 40, piston means 32 and
mandrel free end 36 are disposed in the pipeline and attached to the
downstream end of the pipeline inspection tool 16' (or other inspection
and/or evaluation and/or intervention tool) carrying conventional
centralizers, such as the centralizers 15 shown. The tool may be attached
to a wireline cable 18 for moving the tool 16' during the tool operation
after the propulsion apparatus has initially positioned the tool to a
desired starting/working location. In a pipeline application either
hydraulic or air pressure may be utilized to move the propulsion apparatus
14 within pipeline 10'. Accordingly, as hereinafter used, the term "fluid
pressure" shall include pressure caused by hydraulic pressure of liquids
or a by air pressure caused by compressed air or gases.
Referring now to FIGS. 1, 2, 3A and 3B, a first embodiment of the
propulsion apparatus 14 will now be described in detail. As previously
described, the propulsion apparatus 14 basically comprises a top sub
portion 34 having a male threaded connector 62 and a sealing 0-ring 60 for
mating with the free threaded box end of the selected tool or tool
combination 16(16') (not shown). An elongated tubular mandrel section 30
integrally depends from or is welded to the top sub portion 34 and has an
interior axial bore 56. A transverse port 52 is provided for communication
with the axial bore 56. A cylindrical sleeve 40 is coaxially disposed over
the tubular mandrel 30 and is sized for a close sliding fit over the
mandrel. The top end of the sleeve 44 carries therein a plurality of
circumferentially spaced and radially disposed apertures 46 that are
aligned with a matching set of circumferentially spaced and radially
disposed apertures 46' in the mandrel. In the embodiment shown, shear pins
or screws (not shown for simplicity) would be inserted in the aligned
circumferentially disposed apertures 46/46' to provide some total
predetermined shearing resistance and to position and retain the sleeve 40
in a first position shown in FIG. 3A that closes the transverse port 52
and substantially prohibits fluid communication from the interior of the
tubular member (10, 10') through the transverse port 52 and axial bore 56
for purposes to be hereinafter described in greater detail. The lower free
end 36 of the mandrel 30 has an enlarged portion 35 that provides a
circumferential shoulder 50. Shoulder 50 engages the lower edge 48 of the
sleeve 40 for limiting the downward coaxial sliding movement of the sleeve
40 with respect to the mandrel 30 as more particularly shown in FIG. 3B.
A cup assembly 32 that also functions as piston mean 32 is mounted
circumferentially of sleeve 40. The cup assembly 32 may comprise one or
more fin elements 42 that project radially and circumferentially from the
sleeve 40 and substantially reduce the annular space between the sleeve
and the inner surface of the tubular member 10(10'). The projecting fin
element(s) 42 of the cup assembly act as piston means 32 that cooperates
with the sleeve 40 and the tubular casing walls 10(10') for translating
fluid pressure applied at 17(17'), and developed as a differential
pressure across the cup assembly 32, into propelling forces acting on the
cup assembly/piston means 32 and transferred to the attached sleeve 40.
The propelling forces are controlled by the pressurized fluid forces
exerted at 17(17') by the pump 26 for achieving a preselected force
magnitude and generally act coaxially to the apparatus 14 and cup
assembly/piston means 32 in the direction of the arrows 17(17').
In operation, the propulsion apparatus 14 is attached by the threaded end
62 of the top sub 34 to the lower box end 13 of the tool 16(16') (see
FIGS. 1 and 2) and the tool and propulsion apparatus are inserted into the
tubular member 10(10'). The sleeve 40 and cup assembly/piston means 32 has
been positioned as shown in FIG. 3A with the sleeve 40 covering the
transverse mandrel port 52 in order to substantially prohibit fluid flow
from the interior of the tubular casing/pipe 10(10') through the port 52
and the axial bore 56 disposed in mandrel 30 and communicating with the
free end 36 thereof. A plurality of shear pins (not shown for simplicity)
have been inserted into the registering apertures 46 and 46' of the sleeve
and mandrel, respectively, to position and retain the sleeve in position
shown in FIG. 3A closing the mandrel transverse port as above described.
The pressurized fluid introduced in the casing/pipe 10(10') acts in the
direction of the arrows 17(17') to develop a fluid pressure differential
".DELTA.P" across the cup assembly/piston means 32 in the direction shown.
The developed pressure differential .DELTA.P is translated into forces
having a preselected first magnitude and acting generally coaxially on the
fin elements 42 to apply propelling forces to the cup assembly/piston
means 32 in the direction of the arrows 17(17') in order to exert the
propelling forces on the attached sleeve 40. As long as the propelling
forces created by the differential pressure .DELTA.P are of a first
magnitude that is less than the combined preselected shear resistance
forces of the shear pins disposed in the registering apertures 46 and 46',
the shear pins will hold the sleeve 40 in the first selected position
closing the mandrel transverse port 52 as shown in FIG. 3A and will
transfer the propelling forces acting on the cup assembly and sleeve to
the mandrel 30 and the tool 16(16'). Accordingly, the propulsion apparatus
14 will respond to the differential pressure .DELTA.P and translate the
fluid differential pressure into coaxial forces acting to push the piston
means 32 through the tubular member 10(10 ') in the direction of reduced
fluid pressure, thus acting as a locomotive to "pull" the selected tool
string 16(16') through the tubular member to a desired location.
It is not necessary that the radial tips of the fin elements 42 of the cup
assembly 32 actually "touch" and/or form a "seal" with the interior of the
walls of casing/pipe 10(10'). However, it is necessary that the fins
extend radially outward by a sufficient amount to substantially reduce the
annular space between the tips of the fins and the inner surface of the
tubular member 10(10') in order to prevent any substantial amount of fluid
to bypass the fin elements 42 of the cup assembly/piston means 32 and
insure that a sufficient pressure differential can be developed and
maintained.
When the apparatus 14 and attached tool string 16(16') has been properly
positioned, the logging sequence using the tool 16(16') can begin.
Typically, logging measurements are taken as the logging tool or
instrument 16(16') is raised. Logging speeds are relatively slow and
usually the logging tool 16(16') may be raised with the piston means (cup
assembly) 32 in the position shown in FIG. 3A, since as above described,
there is not necessarily a "seal" between the tips of fins 42 and the
inner surface of the walls of the tubular member 10(10'). As long as the
tool 16(16') is raised at a rate that permits sufficient "flow" or
"leakage" of the fluid past the tips of fins 4 and does not generate
sufficient forces to create a .DELTA.P that will exceed the shearing
resistance of the shear pins disposed in aligned apertures 46/46', the
sleeve 40 will remain in position on the mandrel 30 closing the port 52 as
shown in FIG. 3A.
However, if it is nec | | |
