Note: Descriptions are shown in the official language in which they were submitted.
CA 02483174 2004-09-30
DRILL STRING SHUTOFF VALVE
Related Applications
[0001] This application is related-in-part to Canadian File No. 2,424,608
filed
April 4, 2003, pending.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] This invention relates in general to safety shutoff valves, and
particularly to a
safety shutoff valve located in a drill string for drilling a well.
2. Background of the Invention
[0003] Most oil and gas wells are drilled with a rotary drilling rig.
Typically, the drill
string has a drill bit on the end and is rotated to cause the drill bit to
advance into the
earth. A drilling fluid is pumped down the interior passage of the drill pipe,
which
exits nozzles on the drill bit and flows back up an annular space surrounding
the drill
pipe along with cuttings.
[0004] Normally, the drilling fluid is a liquid called mud, which has a weight
selected
to provide a hydrostatic pressure greater than the expected earth formation
pressures.
When tripping the drill string in and out of the hole, the drilling mud in the
hole and
within the interior of the drill pipe provide sufficient hydrostatic pressure
to prevent a
blowout. However, heavy drilling mud can damage certain earth formations,
reducing
their abilities to produce fluids after completion. For example, methane is
located in
certain fairly deep coal beds. The coal formations may be damaged by
encroaching
drilling mud.
[0005] Drilling with gaseous fluids, such as air, has also been done with oil
and gas
wells. In one of these techniques, compressed air flows down the interior of
the drill
pipe, exits the drill bit and flows back up the annulus. A stripper seal
surrounds the
drill pipe at the surface for sealing the gas pressure in the well. Also,
compressed air
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CA 02483174 2004-09-30
is used as a drilling fluid for drilling shallow mining blast holes. Mining
drilling rigs
may employ a dual passage string of drill pipe, with one of the passages being
an
inner passage and the other an annular passage. A gaseous fluid such as air is
pumped
down the annular passage and flows back up the inner passage along with
cuttings.
The dual passage drill pipe can be rotated to rotate the drill bit.
Alternately, a
downhole motor can be utilized which may also create a reciprocating a hammer
motion as well as rotating the drill bit while the drill pipe remains
stationary.
[0006) The possibility of a blowout due to excessive earth formation pressure
is not a
factor with shallow drilling of mining blast holes. With deep oil and gas
drilling,
however, it must be considered both while drilling and while tripping the
drill pipe in
and out of the hole. Blowout preventers and rams are utilized to seal around
the
annulus of drill pipe. The use of check valves in the drill string has been
proposed in
the past. The primary barrier to a blowout, however, continues to be the use
of
drilling mud with sufficient weight to provide a higher hydrostatic pressure
than any
expected pressure of the earth formations.
SUMMARY OF THE INVENTION
[00071 In this invention, a valve assembly is mounted in a string of drill
pipe for
selectively closing the passages of the drill pipe. The valve assembly
includes an
annular valve assembly carried in an annular passage. The annular valve
assembly
selectively actuates between open and closed positions due to fluid pressure
above the
annular valve assembly. When the fluid pressure in the annular passage above
the
annular valve assembly is less than a predetermined amount, the annular valve
assembly closes. The annular valve assembly opens when the pressure in the
annular
passage above annular valve assembly increases above the predetermined amount.
[00081 The string of drill pipe also includes an inner passage extending
axially
through the drill pipe. The valve assembly includes an inner valve assembly
carried
in the inner passage. The inner valve assembly includes a pair of valve
members that
rotate upon receiving pressure pulses from the surface. The pressure pulses
cause the
valve members of the inner valve assembly to rotate, which actuates the inner
valve
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CA 02483174 2011-05-11
assembly between open and closed positions. Fluid can flow axially upward or
downward through the inner valve assembly while in its open position.
[0008A] The invention in one broad aspect provides an apparatus for opening
and
closing a passage of a drill string, comprising a concentric string of conduit
for
suspending a drill bit and a motor, the concentric string of conduit defining
an inner
passage and an annular passage within the concentric string of conduit, the
inner and
annular passages being independently in fluid communication with the drill
bit. An
inner valve assembly is carried in the inner passage that is selectively
actuated
between open and closed positions for regulating fluid flow through the inner
passage.
An annular valve assembly is carried in the annular passage that is
selectively actuated
between open and closed positions for regulating fluid flow through the
annular
passage.
[0008B] Another aspect of the invention pertains to a method for opening and
closing
a passage of a drill string suspending a drill bit and a motor, comprising
providing a
concentric string of conduit having an inner passage and an annular passage
within the
concentric string of conduit that are independently in fluid communication
with the
drill bit, an inner valve assembly carried in the inner passage, and an
annular valve
carried in the annular passage, opening the inner valve assembly with a
pressure pulse
from the surface that causes the inner valve assembly to rotate into an open
position,
opening the annular valve by supplying fluid pressure in the annular passage
above
the annular valve, and closing the annular valve by discontinuing the supply
of fluid
pressure in the annular passage above the annular valve.
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CA 02483174 2011-05-11
[0009] The valve assembly of this embodiment is particularly for use with a
drill
string for drilling with a gaseous drilling fluid. The drill string is
preferably of a dual
passage type, having an inner conduit and an annular passage surrounding the
inner
conduit. The valve assembly is particularly useful for drill strings that are
coiled
tubing. Because coiled tubing cannot be rotated, the inner and outer valve
assemblies
are actuated by pressure from the surface rather than rotating the drill
string.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Figures 1A and 1B comprise a vertical sectional view of a valve
assembly
constructed in accordance with this invention and shown in an open position.
[0011] Figures 2A and 2B comprise a vertical sectional view of the valve
assembly of
Figures 1A and 1B, but shown in a closed position.
[0012] Figure 3 is a perspective view of part of a lower sub of the outer
member of
the valve assembly of Figures 1A and 1B.
[0013] Figure 4 is a side elevational view, partially sectioned, of the lower
sub of
Figure 3.
[0014] Figure 5 is a sectional view of the lower sub of Figure 3, taken along
the line
5- -5 of Figure 4.
[0015] Figure 6 is a sectional view of the lower sub of Figure 3, taken along
the line
of 6-6 of Figure 4.
[0016] Figure 7A comprises a vertical sectional view of an alternative valve
assembly
constructed in accordance with this invention and shown in an open position.
[0017] Figure 7B is a vertical sectional view of the valve assembly of Fig. 7A
in a
closed position.
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[0018] Figure 8 is an exploded view of a portion, of the valve assembly shown
in
Figures 7A.
[0019] Figure 9 is a vertical sectional view of the valve assembly of Figure
7A
showing the flow of circulation when the valve assembly has its inner and
annular
valves open.
[0020] Figure 10 is a vertical sectional view of the valve assembly of Figure
7A
showing the flow of circulation when the annular valves are open and the inner
valve
is closed.
[0021] Figure 11 is a vertical sectional view of the valve assembly of Figure
7A
showing a flow of circulation when the annular valves are closed and the inner
valve
is open.
[0022] Figure 12 is a vertical sectional view of the valve assembly showing
another
flow of circulation when the annular valves are closed and the inner valve is
open.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0023] Referring to Figure 1, valve assembly 11 includes an outer tubular
member 13,
which is made up of several components. An upper adapter 15 forms the upper
end of
outer memberl3. Upper adapter 15 is a tubular member having threads on its
upper
end for connection to an outer conduit 17 of a dual passage drill string 19.
Drill string
19 preferably has an inner conduit 21 extending through it. An annular passage
23
surrounds inner conduit 21, and an inner passage 25 extends through inner
conduit
21. Inner conduit 21 and outer conduit 17 may be made of continuous coiled
tubing,
which is typically of metal. Alternately, outer conduit 17 may be made up of
segments of pipe secured together, and inner conduit 21 could be formed of
sections
of pipe that stab together.
[0024] Outer member 13 also has an upper sub 27 that secures to the lower end
of
adapter 15. Upper sub 27 is a tubular member that has a plurality of pins 29
secured
to it. Preferably there are two sets. of pins 29, each pin 29 in each set
being axially
aligned with the others in. the same set. The sets of pins 29 are spaced 180
apart and
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CA 02483174 2004-09-30
extend radially inward. Upper sub 27 also has a plurality of spaced apart
downward
facing lugs 31 on its lower end. Lugs 31 contact an upper shoulder of a lower
sub 33
of outer member 13 when valve assembly 11 is in the retracted position shown
in
Figures 1 A and 1 B.
[00251 Lower sub 33 is a tubular member that has an upper reduced diameter
portion
that inserts into upper sub 27 and contains a pair of slots 35 for engagement
by pins
29. Slots 35 are spaced 180 from each other in this embodiment. As shown in
Figure
3, each slot 35 has a plurality of transverse portions 37 that extend
circumferentially
about 90 and are parallel to each other. Each transverse portion 37 is
perpendicular
to the longitudinal axis of lower sub 33 and leads to an axial portion 39 that
extends
along the length of lower sub 33. Each slot 35 does not extend entirely
through the
sidewall of lower sub 33, thus does not communicate with the interior of the
lower
sub 33. Lower sub 33 also has a plurality upward facing lugs 41 that have
spaces
between them for receiving downward facing lugs 31 (Figure 1B) of upper sub
27.
[0026] There are more transverse portions 37 of each slot 35 than pins 29.
Each set
has three pins 29 in this example, while there are four transverse portions 37
(Figure
3) in each slot 35. Pins 29 are located in the lower three transverse slots 37
while
valve assembly 11 is in the open and retracted position of Figures IA and 1B.
While
in this position, lugs 31 and 41 are intermeshed with each other as shown in
Figure
1B. Each space between each upward extending lug 41 is wider than each
downward
extending lug 31. This allows upper sub 27 to rotate counterclockwise (looking
downward) an increment relative to lower sub 33 while lugs 41 and 31 are
intermeshed. While doing so, pins 29 will move from the transverse portions 37
to
the axial portion 39. Then, upper sub 27 can move upward relative to lower sub
33 a
short distance until the uppermost pin 29 of each set (Figure 1B) contacts the
upper
end of axial portion 39. At this point, upper sub 27 can be rotated an
increment
clockwise relative to lower sub 33 to cause the three pins 29 to enter the
upper three
transverse portions 37.
[0027] The total number of transverse portions 37 should exceed the total
number of
pins 29, however the number could differ from the four transverse portions 37
and
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three pins 29 shown in the preferred embodiment. Although lugs 31, 41 allow
limited
rotation of upper sub 27 relative to lower sub 33, they will transmit torque
once in
engagement with each other.
[00281 Referring again to Figure 1B, a lower adapter 43 secures by threads to
the
lower end of lower sub 33. Lower adapter 43 has the same configuration as
upper
adapter 15 for connecting to another portion of drill string 19. Preferably
lower
adapter 43 connects into drill string 19 at a fairly close distance to a drill
motor and
bit assembly (not shown). Outer member 13 thus is made up of upper adapter 15,
upper sub 27, lower sub 33 and lower adapter 43. The upper portion of outer
member
13, which is made up of upper sub 27 and upper adapter 15, will telescope
upward
relative to the lower portion, which is made up of lower sub 33 and lower
adapter 43.
Figures 1A and lB show the retracted position, while Figures 2A and 2B show
the
extended position.
100291 An inner member 45 extends through outer member 13. Inner member 45 has
a number of components, and its outer diameters are all less than the inner
diameters
of adjacent portions of outer member 13, resulting in an annular passage 47
between
inner member 45 and outer member 13. Inner member 45 has a tubular upper
portion
49 that joins inner conduit 21 of drill string 19. Inner upper portion 49 has
outward
extending lugs 50 that are received within a recess of upper sub 27. The
recess is
defined by an upward facing shoulder 52 of upper sub 27 and the lower end of
upper
adapter 15. Lugs 50 are spaced apart circumferentially from each other so as
to not
impede fluid flow through annulus 47. Lugs 50 and shoulder 52 prevent any
axial
movement of inner upper portion 49 relative to upper sub 27.
[00301 Inner upper portion 49 has a valve member 51 formed on its lower end.
Valve
member 51 comprises a tube that has a closed lower end 53. A plurality of
ports 55
are located in the sidewall of valve member 51 directly above closed end 53.
Valve
member 51 lands within a valve sleeve 57, which has an upward facing conical
shoulder 59 that provides a lower limit for the downward travel of valve
member 51.
Valve sleeve 57 sealingly receives closed end 53. A plurality of bypass ports
63 are
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CA 02483174 2004-09-30
located in valve sleeve 57, with each port 63 registering with one of the
ports 55 when
in the open position of Figures IA and I B.
[00311 An inner member lower tube 65 is secured to valve sleeve 57. The inner
diameter of lower tube 65 is greater than the outer diameter of valve sleeve
57 at ports
63 by a selected amount to create an annular clearance 66. While in the
position
shown in Figure 1B, fluid may flow upward, as indicated by the arrows, through
clearance 66, ports 63, 55, and into the interior of valve member 51. Ports 63
and
clearance 66 serve as a bypass to allow flow around closed end 53 of valve
member
51 while in the open position.
[0032] Lower tube 65 is axially retained with a lower portion of outer member
13,
which comprises lower sub 33 and lower adapter 43. This is handled by a
plurality of
lugs 67 on the exterior of lower tube 65. Lugs 67 locate within a recess that
is formed
by a downward facing shoulder 69 of lower sub 33 and the upper end of lower
adapter
43. Lugs 67 are spaced apart circumferentially to allow fluid flow through
annular
passage 47.
100331 An inner passage 71 extends through the various components of inner
member
45. Inner member 45, like outer member 13, has an upper portion that moves
axially
relative to a lower portion. The upper portion is made up of inner upper
portion 49
and valve member 51. The lower portion of inner member 45 is made up of valve
sleeve 57 and lower tube 65.
[00341 In operation, valve assembly 11 is connected into drill string 19 at a
point near
the lower end of the drill string. Typically, the operator would place valve
assembly
11 in a closed position prior to running drill string 19 into the well. This
may be done
at the drill rig floor by restraining lower adapter 43 against rotation while
rotating
outer adapter 13 about one-fourth turn in a counterclockwise direction looking
downward. This causes pins 29 (Figure 1B) to move from transverse portions 37
to
axial portion 39 (Figure 3).. Either before or after the, incremental
rotation, the
operator suspends valve assembly 11 vertically. This causes upper sub 27 and
its pins
29 to move upward relative to lower sub 33 and its slot 35 (Figure 3). When
the
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CA 02483174 2004-09-30
upper pins 29 reach the upper ends of axial slots 39, the operator rotates
upper adapter
15 one-fourth turn back clockwise relative to lower adapter 43. Pins 39 are
now in
the upper three transverse slot portions 37 (Figure 3). Pins 39 and transverse
slot
portions 37 of slot 35 thus serve as a retainer to maintains valve assembly 11
in the
extended position.
[00351 As upper sub 27 moves upward relative to lower sub 33, valve member 51
also moves upward relative to valve sleeve 57. Closed lower end 53 moves
upward to
the position of Figure 2B above ports 63 in valve sleeve 57. Any upward flow
through inner passage 71 will be blocked by closed end 53.
[00361 When the drill bit reaches the bottom of the well, the operator will
open valve
assembly 11 by rotating drill string 19 one-fourth turn counterclockwise.
Because of
the weight of drill string 19 on valve assembly 11, the lower portion of outer
member
13, including lower sub 33, does not rotate, thus causing each set of pins 39
to now
enter axial portion 39 of slot 35 (Figure 3). The operator allows the weight
of the drill
string above valve assembly 11 to move the upper portion of outer member 13
downward relative to the lower portion of outer member 13 until lugs 31
contact the
shoulders between lugs 41. Outer member 13 will then be in compression. At
this
point, pins 29 (Figure 1B) will be in alignment with the three lower
transverse
portions 37 (Figure 3). The operator rotates drill string 19 one-fourth turn
clockwise,
causing upper sub 27 to rotate relative to lower sub 33, placing pins 29 at
the ends of
the transverse portions 37. At the same time the upper portion of outer member
13
moved downward, valve member 51 also moved downward in valve sleeve 57 to the
position shown in Figure 1B. Ports 63 and 55 will now align with each other,
placing
valve assembly 11 in an open position.
[00371 The operator pumps a fluid down annular passage 23, the fluid typically
being
a gas such as air. The fluid flows down annular passage 47 and is used to
drive the
drill motor to rotate the drill bit (not shown) while drill string 19 remains
stationary.
Cuttings and return air flow up inner passage 71, through clearance 66 and
ports 63
and 55 into the interior of valve member 51. The fluid continues to flow up
inner
passage 71 into inner passage 25 of drill string 19. When the operator wishes
to close
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CA 02483174 2004-09-30
valve assembly 11, he simply reverses the steps mentioned above. Normally,
when
tripping the drill string 19 out of the well such as to change the drill bit,
the operator
will close the valve assembly.
[0038] The invention has significant advantages. The valve assembly provides a
safety shutoff to prevent the flow of gas or other formation fluids up through
the drill
string, particularly while running the drill string into the well or
retrieving the drill
string from the well. The valve assembly is particularly useful when drilling
into
deep coal beds that contain methane gas. The use of air as a drilling medium
avoids
having to utilize liquid drilling fluids, which tend to encroach into and
damage such
formations. The valve is easily moved between open and closed positions by
manipulating the drill string. The valve can be retained in either the open or
closed
position.
[0039] Referring to Figures 7A and 7B, an alternative embodiment of valve
assembly
211 is shown for a dual passage conduit 217. Conduit 217 supporting valve
assembly
211 is preferrably a string of coiled tubing. Coiled tubing 217 is unable to
be rotated,
compressed, and extended during drilling operations like the assembly shown in
Figures IA-6, therefore a manner of regulating fluid flow within the conduit
from the
drill bit is desired.
[0040] Valve assembly 211 preferably includes an outer tubular member 213 and
an
inner tubular member 215. Valve assembly 211 is located within a lower portion
of
coiled tubing 217 extending from the surface. In the preferred embodiment,
outer
tubular member 213 is a portion of coiled tubing 217, and inner tubular member
215
within outer member 213 is also a portion of coiled tubing 217. Alternatively,
inner
and outer tubular members 213, 215 of valve assembly 211 can be fixedly
attached to
a dual passage string of coiled tubing 217. Valve assembly 211 supports a
downhole
motor 219 and a drill bit 221 below valve assembly 211. Downhole motor 219 is
preferably a centrifugal motor that is powered, in a manner known by those in
the art,
by fluid transmitted through coiled tubing 217. Motor 219 drives drill bit 221
during
drilling operations.
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CA 02483174 2004-09-30
[00411 The inner surface of outer tubular member 213 and the outer surface of
inner
tubular member 215 define an outer annulus 223 for fluid flow through an outer
passage of coiled tubing 217 to drill bit 221. The interior surface of inner
tubular
member 215 defines an inner passage 225 in fluid communication with the inner
passage of coiled tubing 217 and drill bit 221. Drill bit 221 is in fluid
communication
with inner and outer passages 223, 225 through motor 219.
[00421 Valve assembly 211 preferably includes an annular valve assembly 227
located in outer annulus 223 between outer and inner tubular members 213, 215.
Preferably, a valve seat 229 extends radially outward from the outer surface
of inner
tubular member 215 and sealingly engages the interior surface of outer tubular
member 213. A valve passage 231 extends axially through valve seat 229.
Preferably, there are a plurality of valve passages 231 extending axially
through valve
seat 229 around the circumference of inner tubular member 215. Annular valve
passages 231 thereby provides a plurality of passages 231 for fluid to flow
through
outer annulus 223 between portions of outer annulus 223 above and below valve
seat
229.
[00431 A valve piston 233 regulates flow through valve passages 231. Valve
piston
233 preferably has a circular cross section allowing it to slidingly engage
the outer
surface of inner tubular member 215. Valve piston 233 selectively actuates
between
open and closed positions within valve assembly 227 to regulate flow through
valve
passages 231 by engaging and disengaging valve seat 229. A valve spring 235
located axially below valve piston 233 biases valve piston 233 toward valve
seat 229
and valve passages 231. A spring retainer 237, located below valve spring 235,
provides a physical barrier for spring 235 to engage while biasing valve
piston 233
toward valve seat 229.
[00441 A predetermined fluid pressure within outer annulus 223 above valve
passage
231 to compress valve spring 235 and disengages valve piston 233 from valve
seat
229, thereby opening annular valve assembly 227. Preferably, when fluid
pressure in
the portion of outer annulus 223 is. less than the predetermined amount above
valve
seat 229, valve spring 235 expands against valve piston 233 until valve seat
229 and
CA 02483174 2004-09-30
valve piston 233 are in substantial contact with each other. Therefore,
annular valve
assembly 227 actuates between open and closed positions through pressure
supplied
from the surface through outer annulus 223. When pressure is not supplied
through
outer annulus 223 toward valve assembly 211, annular valve assembly 227 is in
its
closed position as shown in Figure 7B. When pressure is supplied through outer
annulus 223 toward valve assembly 211 annular valve assembly 227 is in its
open
position as shown in Figure 8A.
[0045] Valve assembly 211 also includes an inner valve assembly 241 located
within
in inner tubular member 215. Inner valve assembly 241 preferably includes an
upper
valve member 243 having an upper valve member casing 245, which slides within
the
interior of inner tubular member 215. An upper valve member piston 247 is
located
along a central axis within upper valve member casing 245. An upper valve
member
spider 249 connects a lower portion of upper valve member piston 247 to an
interior
surface of upper valve member casing 245. Upper valve member piston engages
upper valve member casing 245 through upper valve member spider 247 to actuate
upper valve member 243 up and down within inner tubular member 215.
Preferably,
upper valve member piston 247 is selectively actuated through pressure pulses
acting
on an enlarged upper surface of upper valve member piston 247 from the surface
through inner tubular member 215.
[0046] A lower valve member 251, located below upper valve member 243
preferably
includes a lower valve member casing 253 which slides within inner tubular
member
215. An upper surface of lower valve member casing 253 engages a lower surface
of
upper valve member casing 245 as upper valve member 243 actuates up and down
due to the pressure pulses experienced by upper valve member piston 247. Lower
valve member 251 also preferably includes a lower valve member spider 255
extending between interior surfaces of lower valve member casing 253. Lower
valve
member casing 253 preferably includes an inner valve piston 259 that is
connected to
lower valve member spider 255 and extends axially downward through inner
tubular
member 215 and lower valve member 251.
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CA 02483174 2004-09-30
[00471 An inner valve seat 257 is formed within inner tubular member 215 below
lower valve member casing 253 and above a portion of inner valve piston 259.
Preferably, inner valve seat 257 is formed with a circular cross section
having a
smaller radius than lower valve member casing 253. Inner valve seat 257 is
fixedly
attached to inner tubular member 215, thereby remaining stationary relative to
lower
valve member 251 as inner valve piston 259 moves axially upward and downward
inside inner tubular member 215. An inner valve spring 261, located below
inner
valve piston 259, biases inner valve piston 259 axially upward toward upper
valve
member 243 and inner valve seat 257. Preferably, inner valve piston 259 has a
portion which sealingly engages inner valve seat 257 when inner valve piston
259 is
biased upward by inner valve spring 261. When inner valve piston 259 engages
inner
valve seat 257 inner valve assembly 241 is in its open position. When inner
valve
spring 261 is contracted so that inner valve piston 259 is below inner valve
seat 257,
inner valve assembly 241 is in its open position as shown in Figure 7A. An
inner
valve retainer 263 is preferably located below inner valve spring 261 for
providing a
surface against which inner valve spring 261 engages to thereby bias inner
valve
piston 259 axially upward.
[00481 Inner valve spring 261 expands and contracts upon engagement by inner
valve
piston 259. Upward and downward movements of lower valve member casing 253
move inner valve piston 259 axially upward and downward relative to inner
tubular
member 215. Lower valve member casing moves axially upward and downward
relative to inner tubular member 215 due to axial upward and downward movement
of
upper valve member 243, which is actuated by pressure pulses on upper valve
member piston 247.
[0049] Referring to Figures 7A, 7B and 8, a plurality of guide vanes 265 are
preferably formed on the interior surface of inner tubular member 215 within
inner
valve assembly 241. Preferably, guide vanes 265 are formed an axial depth to
engage
upper valve member 243 and the upper surface of lower valve member 251 (as
shown
with dotted lines in Figures 7A and 7B. The lower end of each guide vane 265
preferably includes a sloping face 267. A plurality of upper keys 269 are
formed on
the outer surface of upper valve member casing 245. Upper keys 269 preferably
slide
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CA 02483174 2004-09-30
within guide vanes 265 as upper valve member 243 moves axially upward and
downward relative to inner tubular member 215. Upper keys 269 preferably
include
sloped faces 271 located toward the axially upward portion of upper keys 269.
Sloped faces 271 preferably engage sloped downward faces 267 of guide vanes
265 as
upper valve member 243 slides axially downward relative to guide vanes 265 and
inner tubular member 215.
[0050] The combination of upper sloped faces 271 of upper keys 269 and
downward
sloping faces 267 of guide vanes 265 causes upper valve member 243 to rotate a
predetermined incremental amount. Preferably, there are as many upper keys 269
as
there are slots between guide vanes 265 so that an upper key 269 is always
located
within a guide vane 265 as upper valve member 243 slides axially upward and
downward within guide vanes 265. After being actuated to an axial depth, such
that
the engagement as sloped downward faces 267 of guide vanes 265 and upper
sloped
faces 271 of upper keys 269 causes upper valve member 243 to rotate
incrementally,
each upper key 269 rotates into position for sliding engagement with an
adjacent
guide vane 265.
[0051] Preferably, a plurality of sloped surfaces 273 of upper valve member
casing
245 are formed at the axially lower end of upper valve member casing 245.
Sloped
surfaces 273 preferably include downward facing crests 275 and upward facing
valleys 277. The combination of downward facing crests 275 and upward facing
valleys 277 form a grooved profile for engaging lower valve member casing 253
of
lower valve member 251. Upper keys 269 preferably include lower sloped faces
279.
The slopes of lower sloped faces 279 preferably correspond to sloped surfaces
273 of
upper valve member casing 245. Accordingly, downward crest 275 and upper
valleys
277 are also formed by lower sloped faces 279 of upper keys 269.
[0052] Preferably, a plurality of lower keys 281 are formed around the outer
surface
of lower valve member casing 253. A sloped face 283 is formed toward the
axially
upper portion of lower keys 281 for engaging sloped faces 271 of upper keys
269. A
flat upper face 285 is also formed at an axially upward portion of lower keys
281 for
engaging upper keys 269 at downward facing crest 275. Preferably, lower valve
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CA 02483174 2004-09-30
member casing 253 has sloped surfaces 287 formed on its upper end for engaging
sloped surfaces 273 of upper valve member 245. Sloped surfaces 287 of lower
valve
member 251 preferably include upward protruding crests 289 and downward facing
valleys 291. Preferably, upward facing crests 289 include a flat portion
rather than
protruding to a point. Sloped face 283 of lower keys 281 is formed along one
of
sloped surfaces 287 toward upward protruding crest 289. Preferably, flat
portion 285
of lower key 281 is formed to correspond with the flat upper portion of upward
protruding crest 289. Preferably, lower keys 281 are intermittently spaced
around the
circumference of lower valve member casing 253 so that the number of lower
keys
281 is substantially half the number of upper keys 269 and substantially half
the
number of guide vanes 265.
[00531 Sloped surface 283 engages sloped surface 279 of upper keys so that
lower
valve member 251 rotates an incremental step relative to upper valve member
243.
At one incremental step of lower valve member 251 relative to upper valve
member
243, downward facing crests 275 extend into downward facing valleys 291 while
upward facing crest 289 extend into upper facing valleys 277. While in this
position,
flat portion 285 of lower keys 281 is at a position between upper keys 269.
Upon
sloped surfaces 273 and 287 engaging each other as described. Flat portion 285
of
lower keys 281 engage guide vanes 265 as lower and upper valve members 243,
251
slide axially upward through inner tubular member 215 when flat portion 285 is
located between upper keys 269. Flat portion 285 of lower keys 281 prevent
lower
valve member 251 from sliding axially upward beyond sloped downward faces 267
of
guide vanes 265.
[00541 Upon receiving another pressure pulse, upper valve member 243 slides
axially
downward relative to guide vanes 265 within inner tubular member 215. Sloped
surfaces 273 of upper valve member 243 engage sloped surfaces 287 of lower
valve
member 251 which is being held in place against sloped downward faces 267 of
guide
vanes 265 by inner valve spring 261. As upper valve member 243 continues to
engage lower valve member 251, upper valve member 243 and lower valve member
251 slide axially downward relative to guide vanes 265 so that flat portion
285 of
lower keys 281 are no longer in engagement with sloped downward faces 267 of
14
CA 02483174 2004-09-30
guide vanes 265. While lower valve member 251 is being pushed axially downward
by upper valve member 243, lower sloped faces 279 of upper keys 269 engage
sloped
faces 283 of lower keys 281. The engagement of sloped surfaces 283 of lower
keys
281 and sloped surface 271 of upper keys 269 causes lower valve member 251 to
rotate incrementally relative to upper valve member 243. Upon incremental
rotation,
flat portion 285 of lower keys 281 is engaging the downward facing crest
portion of
upper keys 269 which correspond to downward crests 275 of upper valve member
243.
(0055] As upper valve member 243 and lower valve member 251 continue to move
axially downward relative to guide vanes 265, upper sloped faces 271 of upper
keys
269 engage downward sloping faces 267 of guide vanes 265, which rotates both
upper
valve member 243 and lower valve member 251 in incremental step relative to
guide
vanes 265 and inner tubular member 215. Upon rotating this incremental step,
upper
keys 269 and lower keys 281 are aligned for sliding axially upward within
guide
vanes 265 (not shown). After a pressure pulse through inner passage 275
ceases,
upper valve member 243 and lower valve member 251 slide axially upward through
inner tubular member 215 within guide vanes 265. With lower keys aligned such
that
flat portion 285 is engaging downward facing crest 275 of upper keys and upper
valve
member 243, lower keys 281 are allowed to slide within guide vanes 265 which
allows inner valve spring 261 to push lower valve member 251 axially upward so
that
inner valve piston 259 engages inner valve seat 257 as shown in Figure 7B.
Sloped
face 283 of lower keys 281 slidingly engages the point of downward sloping
faces
267 of guide vanes 269 to rotate lower valve member casing 253 relative to
upper
inner valve member casing 245 another incremental step. When rotated, as shown
in
Figure 7B, flat portion 285 slides partially up lower sloped faces 279 of
upper keys
269. A gap is formed between sloped faces 279, 283 in the closed position
shown in
Figure 7B.
[0056] Upon receiving another pressure pulse through inner passage 225, inner
valve
member 243 engages lower valve member 251 along guide vanes 265. Lower valve
member 251 rotates axially relative to upper valve member due to sloped
surfaces 273
and 287 after sliding axially downward below guide vanes 265. After upper
valve
CA 02483174 2004-09-30
member 243 makes another incremental rotation relative to guide vanes 265 due
to
slope downward face 267 and upper sloped face 271 on upper keys 269 and guide
vanes 265, flat portion 285 of lower keys 281 are positioned within upper
valleys 277
between upper keys 269. In this position, there is no gap between the grooved
profiles of upper and lower casings 245, 253. As lower valve member 251 and
inner
valve member 243 begin sliding axially upward relative to guide vanes 265 and
inner
tubular member 215, flat portion 285 of lower keys 281 engages guide vanes 265
and
thereby prevents lower valve member 251 from sliding axially upward within
guide
vanes 265.
[00571 In operation, an operator has a variety of valve configurations for air
flow
within valve assembly 211. Figures 9 through 12 show various configurations
available to operators using valve assembly 211 during drilling operations.
Referring
to Figure 9, inner valve assembly 241 is shown in its open position as shown
in Figure
7A. In the configuration shown in Figure 9, the operator supplies air through
outer
annulus 223. Providing air through outer annulus 223 opens annular valve
assembly
227 thereby allowing air flow to power motor 219 and to drill bit 221. Air
being
discharged from drill bit 221 flows into inner passage of drill bit 221 or
into an
annular region surrounding drill bit 221 and valve assembly 211 within the
well
formation. Air flowing into the inner opening of drill bit 221 flows through
the
central opening of motor 219 and into inner valve assembly 241. With the inner
valve
assembly in the open position as shown in Figure 9 air and cuttings from drill
bit 221
flow through inner passage 225 to the surface.
[00581 Referring to Figure 10, inner valve assembly 241 is actuated towards
closed
position with a pressure pulse as described above. The operator supplies air
through
outer annulus 223 which in turn opens annular valve assembly 227. Air passing
through annular valve assembly 227 continues through annular passage 223 to
power
motor 219 which drives drill bit 221. Discharged air and drilling cuttings
cannot flow
into inner passage 225 because inner valve assembly is in its closed position.
Therefore, discharged air and drill cuttings from drill bit 221 flow up the
annulus
formed around the exterior of valve assembly 211 within the well formation.
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CA 02483174 2004-09-30
[0059] Referring to Figure 11, an operator has an alternative option of not
supplying
air through outer annulus 223. By not supplying air through outer annulus 223,
annular valve assembly 227 closes therefore blocking flow of air and drill
cuttings up
outer annulus 223 towards the surface. Inner valve assembly 241 is shown in
its open
position in Figure 11. In operation, the operator pumps air down an annular
passage
formed outside of valve assembly 211 and outer tubular member 213 through the
well
formation. Upon reaching drill bit 221, air and cuttings flow into inner
passage 225
and through open inner valve assembly 241 back up to the surface.
Alternatively, as
shown in Figure 12, the operator can pump air through inner passage 225
through
valve assembly 211 to motor 219 and drill bit 221. Like the configuration
shown in
Figure 11, annular valve assembly 227 in Figure 12 is also in its closed
position as
operator is not supplying air through outer annulus 223 through annular valve
assembly 227. Air flowing through inner passage 225 inner valve 211 and out of
inner portion of drill bit 221 flows into the annular chambers of the well
formation
surrounding valve assembly 211 and coiled tubing 217. The discharged air and
cuttings from drill bit 221 flow up an annular portion surrounding coiled
tubing 217
within the well formation being drilled back up to the surface.
[0060] In each of the configurations shown in Figures 9-12, in the event the
operator
needs to shut off all fluid flow within coiled tubing 217 from drill bit 221,
the
operator can close annular valve assembly 227 by discontinuing any downward
air
flow through annular passage 225 with a pulse of air pressure against upper
valve
member piston 247 to cause lower valve member 251 to rotate so that inner
valve
piston 259 engages inner valve seat 257 upon being pushed axially upward with
inner
valve spring 261 after the pressure pulse is completed. Valve assembly 211
provides
a way for the operator to close outer annulus 223 and inner passage 225 during
drilling operations with coiled tubing 217, which cannot be actuated like
valve
assembly 11 shown in Figures IA through 6. Valve assembly 211 provides an
operator deciding to use dual passage coiled tubing with a control system
comparable
to valve assembly 11 shown in Figures 1 A through 6 which requires rotating
and
compressing and retracting the dual passage drill string.
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CA 02483174 2004-09-30
[0061] Coiled tubing 217 cannot rotate like the drill string shown in Figures
lA-6.
Valve assembly 211 provides a way of opening and closing valves in inner and
annular valve passages 223, 225. Valve assembly 211 allows an operator to
regulate
flow through inner and annular passages 223, 225 of coiled tubing 217 for
circulation
of drill cuttings and drilling fluid during drilling operations. Coiled tubing
217 can be
preferable because it is easier to remove for repairs than some other drill
strings.
[0062] While the invention has been shown in only some of its forms, it should
be
apparent to those skilled in the art that it is not so limited but is
susceptible to various
changes without departing from the scope of the invention. For example,
although
the drill strings shown have dual passages within it, the valve assembly could
also
operate with a single passage drill string, with the exterior of the valve
assembly
serving as an annulus passage for return flow.
18
