Note: Descriptions are shown in the official language in which they were submitted.
CA 02483244 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 single passage
drill string is
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CA 02483244 2004-09-30
often used while performing this technique. A stripper seal surrounds the
drill pipe at
the surface for sealing the gas pressure in the well. Also, compressed air is
used as a
drilling fluid for drilling shallow mining blast holes.
[0006] Mining drilling rigs may alternatively 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.
[0007) 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
[0008) In this invention, a valve assembly is mounted in a string of drill
pipe for
selectively closing the inner passage of the drill pipe. The valve assembly
includes an
interior valve assembly located within a central passage of the drill string.
The
interior valve is closed by selective movement of the drill pipe from the
surface.
Preferably, the interior valve may be closed by placing the drill string in
tension. This
may occur while running into the well and also by lifting the drill bit from
the bottom
of the well. Also, preferably a retainer mechanism is employed with the valve
for
retaining the valve in either the open position or the closed position. The
retainer
mechanism is actuated in the preferred embodiment by rotating the drill string
a
selected increment.
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[0009] In the one embodiment, the valve assembly has an outer member and an
inner
member, defining an inner passage and an annular passage for the fluid flow.
The
inner and outer members have upper and lower portions that are axially movable
relative to each other. A valve is mounted in the inner member. The valve has
one
portion that moves with the upper portion of the inner and outer members. The
other
part of the valve remains stationary with the lower portions of the inner and
outer
members. Lifting the upper portion mechanically or hydraulically causes the
two
cooperative portions of the valve to move relative to each other, causing the
valve to
move to a closed position.
[0010] In another embodiment, particularly when the drill string is a dual
passage
type, the valve assembly also includes an annular valve assembly located
within an
annular passage surrounding an inner conduit.
[0011] The valve assembly 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.
Compressed gas flows down the annular passage, and returns up the inner
passage
along with cuttings.
[0011A] In a broad aspect, the present invention seeks to provide an apparatus
for
opening and closing a passageway of a drill string comprising a tubular outer
member
having upper and lower portions that telescopingly engage one another and are
axially
movable relative to each other between a retracted position and an extended
position,
the outer member having a bore through each of the upper and lower portions of
the
outer member. A locking mechanism is located between the upper and lower
portions
of the outer member, the locking mechanism selectively locks the upper and
lower
portions between the retracted and extended positions. A valve member is
carried in
the bore for blocking upward flow through the bore, the valve member being
mounted
to one of the upper and lower portions for movement therewith, and while the
upper
and lower portions of the outer member are in the retracted position, the
valve
member allows upward flow through the bore, and while the upper and lower
portions
of the outer member are in the extended position, the valve member blocks flow
through the bore.
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CA 02483244 2011-05-20
[0011B] In a further aspect, the invention provides an apparatus for opening
and
closing a passageway of a drill string comprising a tubular outer member
having upper
and lower portions that telescopingly engage one another and are axially
movable
relative to each other between a retracted position and an extended position.
The
outer member has a bore through each of the upper and lower portions of the
outer
member. There is a locking mechanism located between the upper and lower
portions
of the outer member, the locking mechanism selectively locks the upper and
lower
portions between the retracted and extended positions. An inner tubular member
is
carried in the bore of the outer member, the inner tubular member defining an
inner
passageway and an annular passageway extending axially through the outer
member.
An inner valve member is carried in the bore for blocking upward flow through
the
inner passageway, the inner valve member being mounted to one of the upper and
lower portions for movement therewith, and while the upper and lower portions
of the
outer member are in the retracted position, the valve member allows upward
flow
through the inner passageway, and while the upper and lower portions of the
outer
member are in the extended position, the valve member blocks flow through the
inner
passageway.
[OO11C] In a still further aspect, the invention comprehends a method for
opening and
closing a passage of a drill string comprising providing a tubular outer
member having
upper and lower portions that telescopingly engage one another and are axially
movable relative to each other between a retracted position and an extended
position.
An inner passageway extends through the upper and lower portions, and a valve
member blocks flow through the inner passageway between upper and lower
portions.
The method further provides for closing the inner passageway by sliding the
upper and
lower portions axially away from each other to the extending position, opening
the
inner passageway by sliding the upper and lower portions axially toward each
to the
retracted position, and selectively locking the upper and lower portions in
the extended
and retracted positions.
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BRIEF DESCRIPTION OF THE DRAWINGS
[00121 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.
[00131 Figures 2A and 2B comprise a vertical sectional view of the valve
assembly
of Figures 1A and 1B, but shown in a closed position.
[00141 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.
[00151 Figure 4 is a side elevational view, partially sectioned, of the lower
sub of
Figure 3.
[00161 Figure 5 is a sectional view of the lower sub of Figure 3, taken along
the line
5--5 of Figure 4.
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[0017] Figure 6 is a sectional view of the lower sub of Figure 3, taken along
the line
of 6-6 of Figure 4.
[0018] Figures 7A and 7B comprise a vertical sectional view of a valve
assembly
constructed in accordance with an alternative embodiment of this invention in
a
closed position.
[0019] Figures 8A and 8B comprise a vertical sectional view of the valve
assembly of
Figures 7A and 7B, but shown in an open position.
[0020] Figures 9A and 9B comprise a vertical sectional view of the valve
assembly of
Figures 7A and 7B, but shown with one valve open and one valve closed.
[0021] Figure 10 comprises a vertical sectional view of a valve assembly
constructed
in accordance with the invention for a single passage drill string and in an
open
position.
[0022] Figure 11 comprises a vertical sectional view of the valve assembly of
Figure
10, but shown in a closed position.
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
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CA 02483244 2004-09-30
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
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 1A and 1B.
[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.
[00261 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 1A 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 I B) 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.
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[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
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.
[0028] 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 IA and 113 show the retracted position, while Figures 2A and 2B show
the
extended position.
[0029] 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.
[0030] 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.
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Valve sleeve 57 sealingly receives closed end 53. A plurality of bypass ports
63 are
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 1B.
[0031] 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.
[0033] 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.
[0034] 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 113) 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
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29 to move upward relative to lower sub 33 and its slot 35 (Figure 3). When
the
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.
[0035] 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.
[0036] 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 1.3 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.
[0037] 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
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passage 71 into inner passage 25 of drill string 19. When the operator wishes
to close
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.
[00381 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.
[00391 Referring to Figures 7A through 9B, an alternative valve assembly 111
shows
an apparatus that is capable of locking an inner passageway 171 and annular
passage
147. A valve member 151 operates substantially the same as valve member 51
shown
in Figures 1A through Figure 6. In valve assembly 111, an additional annular
valve
assembly 181 regulates fluid flow through annular passage 147. In this
alternative
embodiment, an outer tubular member 113 includes an upper adapter 115
extending
axially upward from upper sub 127, which is another portion of outer member
113,
and located above valve member 151. Upper adapter 115 connects to an outer
conduit 117 of a dual passage drill string 119.
[00401 An inner member 145 extends axially upward from upper sub 127 through
upper adapter 115 away from valve member 151. Inner member 145 defines an
inner
passage 125. Inner member 145 and upper sub 127 also defines an annular
passage
123. Both inner and annular passages 123, 125 extend axially upward from valve
member 151, toward valve assembly 181.
[00411 Outer tubular member also includes an annular valve housing 183 that
receives an upper portion of upper adapter 115 and encloses the inner portions
of
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valve assembly 181 from the well formation.. Annular valve assembly 181 also
includes a valve portion 185 of inner tubular member 145 extending axially
through
annular valve assembly 181. Inner passage 125 extends axially through valve
portion
185 of inner tubular member 145. Valve portion 185 provides a physical barrier
to
the gaseous fluid flowing through annular passage 147 from entering inner
passage
125 within annular valve assembly 181. A valve seat 187 is formed on the outer
surface of valve portion 185 of tubular member 145. Valve seat 187 preferably
extends radially outward from the outer surface of valve portion 185 of inner
tubular
member 145. The combination of valve seat 187, the inner surface of annular
valve
housing 183 and the outer surface of valve portion 185 defines upper and lower
annular valve chambers 189, 191. Annular passage 147 extends axially upward
from
valve assembly 151 toward valve assembly 181 and opens into lower annular
valve
chamber 189. Annular passage 123 extends axially downward toward valve
assembly
181 and opens into upper annular valve chamber 191.
[0042] An annular valve passage 193 extends axially through valve seat 187.
Preferably, there are a plurality of axial annular valve passages 193
extending through
valve seat 187. Lower chamber 189 and upper chamber 191 are in fluid
communication with each other through annular valve passages 193. A valve
piston
195 selectively engages valve seat 187 and annular valve passages 193 to open
and
close valve assembly 181. Preferably, valve piston 195 surrounds the outer
surface of
valve portion 185 of inner tubular member 145. Preferably, valve piston 195 is
located below valve seat 187 and slidingly engages valve portion 185 for
selective
engagement with valve passages 193.
[0043] A valve spring 197 located below valve piston 195 biases valve piston
195
toward engagement with annular valve passages 193 and valve seat 187. A spring
retainer located below valve spring 197 provides a physical barrier that
engages valve
spring 197 and forces valve sprint 197 to bias valve piston 195 toward valve
seat 187.
Preferably, valve spring 197 has a predetermined spring coefficient such that
a
predetermined gaseous fluid pressure in annular passage 123 actuates valve
spring
197 away from valve seat 187 so that valve assembly 181 is in an open position
as
shown in Figure 8A.
CA 02483244 2004-09-30
[0044] When the gaseous fluid pressure within annular passage 123 is below a
predetermined amount valve spring 197 actuates valve piston 195 toward valve
seat
187, thereby closing valve passages 193 and blocking fluid flow from lower
chamber
189 to upper chamber 191. Valve piston 195 is shown in its closed position in
Figure
7A.
[0045] Figures 7A through 9B show a variety of arrangements for operators to
utilize
during operations. Figure 7A and Figure 7B show valve assembly 111 with valve
member 151 and annular valve 181 in their closed positions. Valve member 151
is
actuated in substantially the same manner as valve member 51 is actuated in
Figures
IA through 6. Figures 8A and 8B show valve assembly 111 with valve member 151
in its closed position thereby preventing flow of fluid through inner passage
125,
while annular valve 181 is in its open position thereby allowing gaseous fluid
flow
through annular passage 123, 147. Figures 9A and 9B show valve member 151 in
its
open position thereby allowing flow of fluids through inner passage 125, while
annular valve passage 181 is in its closed position thereby blocking fluid
flow
between annular valve passage 123, 147. Valve assembly 111 provides an
operator
with an additional way to close fluid flow during drilling operations through
both the
inner and outer passages extending up through dual passage drill string 119.
When it
is desired to shut down fluid flow through outer passages 123, 147, operator
merely
stops supplying fluid through valve assembly 181.
[0046] Referring to Figures 10 and 11, another alternative valve assembly 211
is
shown for use in drilling operations when a single passage dual string is
desired.
Outer tubular member 213 preferably includes an upper adapter 215 connected to
a
single passage drill string 217. Upper adapter 215 connects single passage
drill string
217 to valve assembly 211. Upper adapter 215 includes a tubular member portion
extending axially downward within portions of outer tubular member 213 below
upper adapter 215. Outer tubular member 213 preferably includes an upper sub
227
that attaches to and encloses a portion of upper adapter 215 above tubular
member
248. Upper sub 227 extends axially downward and encloses a substantial portion
of
tubular portion 248 of upper adapter 215. Tubular member 248 has an axial bore
defining inner passage 225 which is in fluid communication with the interior
of
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CA 02483244 2004-09-30
v ,t
conduit 217. Upper sub 227 is substantially similar to upper sub 27 shown in
Figure
1A through Figure 6, upper adapter 215 is substantially similar to upper
adapter 15
and tubular upper portion 49 shown in Figure IA through Figure 6 except that
there is
not an annular passage 23 extending therethrough.
[0047] A lower connector 244 extends below valve assembly 211 toward a drill
motor
and drill bit (not shown). Lower connector 244 preferably includes a lower sub
portion 233 and a lower adapter portion 243. Lower sub portion 233 extends
between
tubular member 248 and upper sub 227 from below upper sub 227. Lower adapter
portion 243 connects to a lower end of lower sub portion 233, or forms the
lower
portion of lower connector 244 below lower sub portion 233, and extends
axially
downward below valve assembly 211 toward the drill bit (not shown). Lower
adapter
portion 243 defines a lower passage 271, which is part of inner passage 225
extending
through conduit 217, and valve assembly 211.
[0048] A plurality of pins 229 engage a plurality of slots 235 in
substantially the same
manner as pins 29 and slots 35 engage each other in Figures IA through Figure
6.
Pins 229 slide through slots 235 along axial portions (39 as shown in Figures
3 and 4)
for allowing valve assembly 211 to move between its extended and retracted
positions
to open valve assembly 211. Pins 229 slide through traverse portions (37 as
shown in
Figures 3 and 4) while actuating valve assembly 211 between its extended and
retracted positions as shown in Figures 10 and 11 in substantially the same
manner as
the invention shown in Figures IA through 6.
[0049] A valve member 251 is positioned toward a lower portion of tubular
member
248 for regulating flow through inner passage 225. Valve member 251 sealingly
engages an interior surface of lower sub portion 233 while valve assembly 211
is in
its extended position shown in Figure 10. Valve member 251 extends below lower
sub portion 233 and into lower adapter portion 243 while valve assembly 211 is
in its
retracted position to thereby open valve assembly 211. Valve member 251
includes a
lower end 253 which prevents fluid flow through inner passage 225 while valve
assembly 211 is in the extended position shown in Figure 11. Valve member 251
preferably includes a plurality of ports 255 extending through a side of
tubular
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member 248. When valve assembly 211 is in its retracted position, ports 255
extend
below lower sub portion 233 and allow fluid flow through valve assembly 211
and the
entirety of inner passage 225.
[0050] An annular clearance 267, formed within lower adapter 243, allows
gaseous
fluid flow around valve member 251 to ports 255. Preferably, lower adapter
portion
243 includes a valve receiving portion 283 having an inner circumference
larger than
the inner circumference of lower sub portion 233. The larger inner
circumference of
valve receiving portion 283 defines annular clearance 267 around valve member
251.
Lower adapter portion 243 also includes a fluted portion 281, which increases
in
diameter between the portion of lower adapter 243 defining lower inner passage
271,
and receiving portion 283.
[0051] In operation, when valve assembly 211 is in its retracted and open
position,
gaseous fluid flows upward from the drill bit (not shown) through inner
passage 271
toward valve assembly 211. Fluid flows from valve passage 271 through fluted
portion 281 into valve receiving portion 283 surrounding valve member 251,
which is
extending below lower sub portion 233 into lower adapter portion 243. Fluid
flows
from valve receiving portion 283 through valve ports 255 into valve member
251.
From valve member 251 fluid can flow within inner passage 225 through valve
assembly 211 to conduit 217. Alternatively, fluid flow can be reversed so that
the
gaseous fluid flows down inner passage 225 and through valve assembly 211 and
into
inner valve passage 271 before discharging into the well formation through
drill bit
221. The gaseous fluid and cuttings circulate to the surface along the outer
surface of
conduit 217. Referring to Figure 11, while valve assembly 211 is in its
extended or
closed position, valve member 251 sealingly engages the inner surface of lower
sub
portion 233. Closed lower end 253 prevents fluid flow between inner passage
225
and inner passage 271. As mentioned previously, valve assembly 211 is actuated
between its extended and retracted positions shown in Figures 10 and 11 in the
same
manner as valve assembly 11 in Figures 1 A through Figure 6 is actuated
between
extended and retracted positions.
13
CA 02483244 2004-09-30
[00521 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, while
the
valve shows a valve member that moves with the upper portion of the valve
while the
valve sleeve remains stationary with the lower portion of the valve assembly,
these
could be reversed. Furthermore, the pins could protrude outward from an inner
member and the slot located on an inner diameter of an outer member.
14
