Inflatable packer with port collar valving and method of setting

An inflatable packer 10 includes a sliding collar 86 which opens and closes port 94 to control pressurization of the inflatable packer element 120 with a cementatious fluid. The collar 86 is axially moveable by a setting tool 20 suspended in the well from a work string WS. An annular passageway 76 in the packer body extends from the inlet port 94 to the packer element 120 to provide for reliable inflation with the cementatious fluid. The collar 86 provides metal-to-metal sealing engagement with the radially inner sleeve 76 of the packer body to reliably seal the inflation chamber from the well fluids when the collar 86 is moved closed.

FIELD OF THE INVENTION 
The present invention relates to an inflatable packer and particularly to 
an inflatable packer with a large flow path capable of transmitting a 
cement or epoxy to an inflation chamber to inflate the elastomeric packer 
element. The invention also relates to an improved technique for 
activating an inflatable packer utilizing mechanically transmitted forces 
to open a port collar valve for inflating the packer. Multiple packers can 
be reliably inflated in a single trip, and drill out of plugs is avoided. 
BACKGROUND OF THE INVENTION 
Various techniques have been proposed for placing cement in an annulus 
between downhole tubulars in order to seal between different zones 
otherwise in fluid communication with the same annulus. In some 
applications, the placement of a cement plug in the annulus may be 
completed by pumping cement downhole and opening a valve to pump the 
cement directly into the annulus. In highly inclined (non-vertical) wells, 
gravity tends to cause the pumped cement to fill the bottom of the 
annulus, and a reliable seal between the tubulars is typically not 
effected in the top of the annulus. Since reliable placement of cement may 
be significantly affected by gravity, this technique is not typically 
utilized in highly deviated or horizontal wellbores. U.S. Pat. Nos. 
2,435,016, 2,659,438, and 3,464,493 each disclose downhole valves for 
pumping cement into an annulus about a tubular. U.S. Pat. No. 2,435,016 
discloses a technique capable of multiple stage cementing. U.S. Pat. No. 
3,464,453 discloses a port collar for a well casing to pack a wellbore 
with cement. 
In order to achieve a more reliable seal in the annulus between downhole 
tubulars, cement has been used to inflate a packer for sealing this 
annulus. The elastomeric packer element acts as an initial seal between 
the tubular on which it is positioned and the surrounding tubular or the 
wall of an open hole. An inflation chamber radially inward of the 
elastomeric packer element serves as a receptacle for the cement or epoxy, 
which acts as the inflation fluid. Corrosive fluids are commonly contained 
in the flow stream of hydrocarbon recovery wells and thus result in the 
potential failure of the sealing function of the elastomeric packer 
element over an extended period of time. Cement or epoxy, once hardened 
within the inflation chamber, thus creates a permanent annular plug 
between the tubular on which the packer is positioned and the surrounding 
tubular or open hole. U.S. Pat. No. 5,488,944 discloses an inflatable 
packer which utilizes a chemical accelerating agent for hardening the 
cement used to inflate the packer element. 
Conventional inflatable packers have valves to inflate the elastomeric 
packer element positioned within small diameter ports passing through the 
sidewall in the packer body and to the inflation chamber. Although these 
packers have been used for cementing operations, the small diameter ports 
and associated valving tend to plug with particles commonly carried by the 
cement slurry. Accordingly, packers especially designed for cement 
plugging operations may use an annular passageway between a radially inner 
sleeve and a radially outer sleeve to reliably transmit the cement or 
epoxy to inflate the packer element. U.S. Pat. No. 3,948,322 discloses a 
multiple stage packer with a sliding sleeve and an annular passageway for 
transmitting cement to inflate the packer element. U.S. Pat. No. 4,499,947 
discloses an inflatable packer with both first and second sleeves for 
controlling inflation of the packer element. U.S. Pat. No. 5,024,273 
discloses a complex tool with a stage collar for inflating the packer. 
U.S. Pat. No. 5,109,925 discloses a multiple stage inflation packer with a 
rupture disk. U.S. Pat. Nos. 5,314,015, 5,315,662 and 5,400,855 each 
disclose inflation packers with multiple sleeves, valves, and/or rupture 
disks. U.S. Pat. No. 5,383,250 discloses an inflation packer adapted for 
coiled tubing operations. 
The above-described inflatable packers are complex and thus expensive. 
Multiple sleeves, rupture disks, and/or other valves increase the 
complexity of the inflatable packer and generally reduce the flow 
capacity. Long term reliability of the set packer may be questionable 
since corrosive fluids and/or high temperature fluids may attack the 
elastomeric seals which seals the ends of the packer inflation chamber. If 
these elastomeric seals fail prior to curing the cement, a leak path past 
the cement plug may be formed, although that leak path may not be 
detectable until after the packer has been set and the hydrocarbon 
recovery system is brought into operation. Other inflatable packers cannot 
pressure test the seals to ensure that the packer chamber is reliably 
sealed with the cementatious inflation fluid. 
A significant disadvantage of prior art inflatable packers of the type 
intended for inflation with a cementations fluid is that the valving to 
the inflation chamber is hydraulically activated. A plug or a ball is 
typically dropped from the surface for sealing engagement with a seat, 
after which a cement slurry is transmitted to the packer inflation 
chamber, followed by another plug or ball. Fluid pressure in the well is 
thus increased to open the valve to the inflation chamber, thereby 
allowing the cement slurry to inflate the sealing element. While plugs or 
balls have long been used to set inflatable packers, the reliability of 
the setting operation is particularly suspect when the packer is used in 
highly deviated or horizontal wellbores, since gravity does not assist in 
controlled movement of the plug and since plugs do not reliably flow past 
corners or sharp deviations in a deviated well. 
After the cement has cured or after another valve of the inflatable packer 
has been closed, the cement still within and above the bore of the packer 
is drilled out, along with the plugs or balls, thereby re-establishing a 
full bore through the set packer. Even if the quantity of cement may be 
precisely controlled to fully inflate the packer without excess cement 
being in the bore, the plugs or balls still must be removed to establish 
full bore capability. With any drill out operation, and most commonly with 
operations involving highly deviated or horizontal boreholes, there is a 
risk that the drill bit may inadvertently penetrate the casing, thereby 
causing significant repair costs and down time. 
In other applications, it would be desirable to set the packer in a well 
along a casing string which includes perforations or slots in the casing 
above the packer. These perforations or slots need to be closed off or a 
bypass placed around the perforations or slots within the casing for the 
hydraulically set packer to be filled with cement or other inflation 
fluid. As a practical matter, the cost of temporarily closing off or 
bypassing the perforations or slots are so high that inflatable set 
packers are not frequently used in casing strings which include the slots 
or perforations. 
Another significant disadvantage of prior art inflatable packers is that 
multiple packers cannot be placed along a casing string and each packer 
reliably activated hydraulically to open a valve and inflate the sealing 
element with cement or another inflation fluid. Wiper plugs positioned 
below and above the cement column are sized for sealing engagement with an 
inflatable packer. As a practical matter, however, it is difficult if not 
impossible to ensure that a wiper plug will properly seat with its desired 
packer but will not inadvertently cause the activation of other packers 
through which the plug passes while flowing down to its desired packer 
seat. While different size plugs may be used, the plugs conventionally 
seal with the casing to prevent the escape of cement from the column as it 
is pumped downhole to the desired packer. As a practical matter, 
therefore, casing strings which include inflatable packers typically 
cannot reliably inflate more than two hydraulically set packers within the 
casing ming and reliably ensure that the wiper plugs do not inadvertently 
cause the opening of an unintended packer positioned along the casing 
string. If the valve is inadvertently opened by a wiper plug and cement is 
unintentionally pumped into the inflated packer, the operator at the 
surface may not realize that the wrong packer in the casing string has 
been inflated until after the cement hardens. Accordingly, an expensive 
mill out operation may be required to cure the problem caused by the 
inadvertent hydraulic setting of an inflation packer. 
The disadvantages of the prior art are overcome by the present invention, 
and an improved inflatable packer is hereinafter disclosed which is 
particularly well suited for inflation with cement or an epoxy to form a 
permanent plug in a wellbore. The techniques of the present invention 
allow for the reliable setting of multiple inflatable packers within a 
casing string, and avoid significant problems involving drill out of 
plugs. 
SUMMARY OF THE INVENTION 
The inflatable packer of the present invention preferably includes a single 
valve collar which is opened and closed by forces mechanically transmitted 
from the surface to the packer, thereby inflating then subsequently 
closing off the packer inflation chamber. Mechanical forces may be 
transmitted through a work string and a setting tool to open and close the 
collar. The sliding collar includes a flange or other stop member for 
locked engagement with the setting tool. The work string may be slacked 
off to lower the collar and open a large port for transmitting cement from 
the work string to the packer inflation chamber. After setting the packer, 
the work string may be pulled up for returning the collar to its upward 
position while making up a metal-to-metal seal both above and below the 
port and between the collar and the packer body, thereby ensuring that 
corrosive fluids are sealed from the inflation chamber. Fluid pressure may 
subsequently be increased in the annulus between the work string and the 
casing to reverse circulate the cement slurry back to the surface through 
the work string. Accordingly, expensive and time-consuming drill out 
operations are avoided. By avoiding plug drill out operations, 
inadvertently drilling through the casing string during drill out is 
eliminated. 
Since the valve for controlling opening and closing of the inflation 
chamber is mechanically activated, multiple packers positioned along the 
casing string may each be selectively activated at any time. The setting 
tool includes a profile for engagement with the collar of the inflatable 
packer to be actuated, although the tool may be easily raised or lowered 
past one or more similar inflatable packers then positioned at a desired 
setting for engagement with the desired inflatable packer to activate that 
packer. Multiple packers may thus be reliably set with the same setting 
tool in a single trip of the work string. The packer setting operation may 
also be used to activate packers positioned along a casing string with 
perforations or slots in the casing string, since the inflation fluid is 
transmitted to the packer through a work string rather than through the 
casing string. 
The integrity of the seals above and below the port in the packer body may 
be pressure tested once the collar is closed and, if necessary, the collar 
may be reclosed until reliable seals are made up. The make up of 
metal-to-metal seals between the collar and the packer body ensures that 
corrosive fluids will not enter the sealing chamber, and allows the packer 
to be reliably used in high temperature applications. 
It is an object of the present invention to provide an inflatable packer 
adapted for pumping a cementations fluid into the inflation chamber 
whereby the casing string on which the packer is positioned may be opened 
to full bore without drill out of plugs used in the inflation operation. 
The packer is well adapted for use in highly deviated and horizontal bore 
holes which cannot reliably transmit plugs to the packer. The risk of 
inadvertent drilling a hole in the casing is eliminated by avoiding the 
plug drill out operation. The packer of the present invention includes a 
valve collar which may be reliably operated for opening and closing even 
when the packer is used in a downhole environment wherein the casing 
string and/or the packer is subject to high bending loads which are 
commonly encountered in highly deviated or horizontal wells. 
It is another object of the invention to provide an inflatable packer of 
the type wherein the inflation chamber may be sealed by mechanically 
opening and closing a valve collar. Multiple packers may be positioned 
along the casing string and each packer selectively inflated by 
manipulating a running tool in a single trip of the work string. Inflation 
fluid is transmitted to the packer through the work string, so that the 
packer may be reliably set in a casing string with slots or perforations 
above the packer. 
It is a feature of this invention that the inflatable packer includes a 
single valve collar which is mechanically opened and closed with sliding 
movement, thereby reducing the complexity of the tool. When the collar is 
moved closed, the seal between the collar and the packer body may be 
pressure tested to ensure reliable sealing engagement. 
Still another feature of this invention is that the opened collar may 
expose a plurality of large ports for transmitting cementations fluid to 
an annular passageway extending axially from the collar to the inflation 
chamber. 
Yet another feature of this invention is that the sliding collar includes a 
metal-to-metal seal so that the packer may be used in high temperature 
applications with the inflation chamber remaining sealed from the downhole 
fluids. The metal-to-metal seals significantly reduce or eliminate the 
effects of corrosive well fluid which deteriorate seals normally provided 
in packers for sealing the inflatable chamber. Long term reliable 
operation of the packer is enhanced by providing metal-to-metal seals 
between the sliding collar and the packer body. 
An advantage of the inflatable packer according to the present invention is 
that the packer may be reliably used in applications wherein elastomeric 
seals are prohibited for downhole tools. The packer according to the 
present invention includes metal-to-metal seals for sealing between the 
sliding collar and the packer body, with elastomeric seals optionally 
providing redundant sealing effectiveness and preferably being positioned 
upstream from the metal-to-metal seals. 
Another advantage of the present invention is that the metal-to-metal seals 
between the sliding collar and the packer body may be formed by slacking 
off the work string and subsequently pulling upward with a large axial 
force on the work string to jerk the collar upward into sealing engagement 
with tapered metal sealing surfaces on the packer body. By providing a low 
angle engagement surface between the metal collar and the metal packer 
body and by supplying a sufficient axial force to the work string, the 
likelihood of the sealed collar subsequently inadvertently dropping to an 
open position is eliminated or substantially reduced. 
These and further objects, features, and advantages of the present 
invention will become apparent from the following detailed description, 
wherein reference is made to the figures in the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 depicts an exemplary application for the present invention. 
Inflatable packers are commonly used in hydrocarbon recovery operations 
for isolating geological zones. A borehole B may be drilled through an 
upper hydrocarbon zone UHZ, through a non-hydrocarbon bearing shale zone 
SZ, and then through a lower hydrocarbon zone LHZ. The inflatable packer 
may thus be used to isolate these zones and thereby maximize recovery of 
hydrocarbons. Although FIG. 1 depicts the wellbore B as being vertical, 
those skilled in the art will appreciate that the inflatable packer of the 
present invention is particularly well suited for use in highly deviated 
and horizontal boreholes. In those applications, the borehole may still 
traverse geological zones, and the inflatable packer may be used to 
fluidly isolate zones from each other. Highly inclined or horizontal 
wellbores thus typically pass through various permeable layers which 
contain hydrocarbons, with the permeable layers being separated by 
impermeable layers which typically include shale or granite. The 
hydrocarbon producing layers are fluidly isolated in order to selectively 
produce the hydrocarbons. According to the method of the invention, this 
isolation is achieved by using an inflatable packer to seal between the 
outside of the casing C and the open borehole B. In order to achieve long 
term sealing effectiveness, the inflatable chamber of the packer may be 
filled with a cementatious fluid. 
FIG. 1A depicts the lower end of an inflatable packer positioned along a 
casing string C and borehole B. The packer 16 is shown in its inflated 
position so that the annulus between the casing C and the borehole wall is 
plugged by the set packer 16. For this exemplary embodiment, the fluid 
used to inflate the packer is a cementatious fluid which is a slurry when 
pumped into the packer, and hardens to form a permanent plug. The term 
"cementatious fluid" as used herein refers to any type of slurry which may 
be used in downhole operations to form a plug, including compositions such 
as a cement slurry, a curable polymer or plastic, or an epoxy. As shown in 
FIG. 1A, the inflatable packer 16 thus isolates the UHZ from the SZ. 
Packer 16 may be identical in construction and operation to the inflatable 
packer 10 discussed below and generally shown in FIG. 1B. 
The lower end of the packer 16 is interconnected with the casing C by 
conventional threads 18. The casing C extends through the SZ, and supports 
another inflatable packer 10 positioned in the well (see FIG. 1B) so that 
the inflatable packer element 120 is generally at the interface between 
the SZ and the LHZ. Those skilled in the art will appreciate that numerous 
inflatable packers may be positioned along a casing string in a wellbore, 
and that only two packers are shown in FIG. 1 for simplicity. The packers 
of the present invention are designed such that a number of packers may be 
positioned axially at selected locations along a casing string, and each 
packer may be selectively inflated as described hereafter. Also, those 
skilled in the art should appreciate that the term "casing" or "casing 
string" as used herein refers to any tubular member of the type which may 
be positioned downhole for supporting an inflatable packer. 
Referring to FIG. 1B, the inflatable packer 10 is shown in its run-in or 
deflated position. Packer 10 comprises an upper body 12 which is discussed 
subsequently and supports the valve collar, and a lower body 14 which 
includes an elongate elastomeric packer element 120 which inflates in a 
conventional manner. The upper body 12 of the packer is thus connected to 
the casing C by threads 19, and the lower body 14 is similarly 
interconnected with casing C by threads 18. The term "elastomeric packer 
element" or "packer element" as used herein refers to any type of 
generally tubular bladder which may be inflated during actuation of the 
packer. Elastomeric packer elements are well known in the art, and 
numerous such packer elements are generally disclosed in the prior art 
discussed earlier. 
FIG. 1A also depicts a work string WS positioned within the casing C and 
passing through the throughbore in the packer 16. The term "work string" 
as used herein refers to any type of tubular string conventionally used to 
mechanically set downhole tools, including tubing strings interconnected 
by threaded connections or coiled tubing. Secured to the work string WS is 
a actuation tool 20 which as depicted is positioned below the packer 16. 
The work string WS may also extend below the actuating tool 20, and 
includes an internal bore or flow path which is sealed from the interior 
of the casing string C. Those skilled in the art will appreciate that the 
work string WS may be lowered so that the tool 20 is positioned for 
activating the packer 10 as discussed subsequently. Actuating tools 20 are 
well known in the art and accordingly details regarding the actuating tool 
20 are not discussed herein. A suitable actuating tool 20 according to the 
present invention for activating an inflatable packer is the TAM 
Combination Tool. 
Internal to the body of the inflatable packer 10 is a collar 86 which is 
movable along the axis of the packer to allow exposure of a port from the 
interior of the casing to the inflation chamber radially within the 
expandable packer element. Fixed tubes create an annular passageway 76 for 
flow of the inflation fluid from the port into the inflation chamber. The 
inflatable element 120 is attached to the outer tube, while the casing is 
attached to the inner tube for supporting the tensile loads transmitted 
through the packer. A sub 122 is attached to a lower end of the inflatable 
element to provide an outer seal with the casing at the lower end of the 
inflation chamber. 
The collar 86 as disclosed herein is a sliding sleeve which is opened and 
closed with an axial motion transmitted to the sleeve by the setting tool. 
Referring again to FIG. 1A, the setting tool 20 includes dual opposing 
seal cups 42 and 54 and contains spring-loaded dogs 58 for opening and 
closing the collar. The setting tool 20 also contains an internal bypass 
to facilitate running in and out of the hole. A shear choke sub may be 
incorporated in the setting tool for quick filling of the work string and 
dumping the work string fluid when the packer inflation job is complete. 
The valve collar may alternatively be opened and closed by torque 
transmitted to the collar through the setting tool. The collar may thus be 
opened with left-hand torque and closed with right-hand torque transmitted 
through the work string WS. The collar includes slots to receive 
spring-loaded dogs on the setting tool to provide a positive indication 
that the setting tool has landed in the collar. The setting tool will not 
pass through the collar while the dogs are engaged. Multiple packers can 
thus be run on one casing string and each packer selectively opened and 
closed in a single trip of the work string and the setting tool. 
Referring now to FIG. 2, the upper body 12 is depicted with the components 
on the right side of the centerline 11 in the valve closed or run-in 
position, and the components on the left side of the centerline 11 shown 
in the valve open or inflated position. The upper sub 70 of the packer 10 
includes conventional threads 19 for threaded engagement with the casing 
C. An outer tube 72 extends downwardly from the sub 70 and may be 
interconnected therewith by threads, keys or other conventional securing 
members 78. An inner tube 74 also generally extends downwardly from the 
sub 70, and is interconnected therewith by threads or other conventional 
securing members 80. The outer tube 72 is sealed to the sub 70 by o-ring 
seal 82, which prevents well fluids in the borehole B from communication 
with the interior of the packer 10. O-ring seal 84 and metal-to-metal seal 
85 similarly seal between the sub 70 and the inner tube 74. As shown in 
FIG. 2, an elongate annulus 76 is thus formed between the outer diameter 
of the tube 74 and the inner diameter of the tube 72. One or more 
circumferentially spaced radial ports 94 are provided within the inner 
tube 74. Ports 94 are normally blocked by the valve collar 86. When the 
valve collar 86 is open, as shown on the left side of FIG. 2, fluid from 
the work string WS may pass through one or more ports 94 and then through 
the annular passageway 76 to inflate the packer, as explained 
subsequently. 
The valve collar 86 is a sleeve-shaped member which is axially moveable 
from the open position, as shown on the left side of FIG. 2, to the closed 
position, as shown on the right side of FIG. 2. The opening and closing of 
the valve collar 86 may be repeated as desired. When in the closed 
position, the upper end of the valve collar 86 may engage the stop surface 
106 formed at the lower end of the sub 70. When in the fully opened 
position, the lower end of valve collar 86 may similarly engage the stop 
surface 108 on the sub 110. The valve collar includes an upper annular 
seal 90 for sealing engagement between the valve collar and the inner 
cylindrical surface 88 of the inner tube 74 and above the one or more 
ports 94. When the valve collar is in the closed position, a lower 
elastomeric annular seal 92 provides similar sealing engagement between 
the valve collar and the inner tube 74 at a position axially below the one 
or more ports 94. Various types of elastomeric sealing members may be used 
in the valve collar according to the present invention, including seals 
fabricated from rubber and plastics. 
The valve collar 86 includes an annular upper recess 96 and an annular 
lower recess 98 with a circumferentially spaced projection 102 
therebetween. As shown in FIG. 2, the projection 102 does not extend 
circumferentially fully around the valve collar, and instead one or more 
circumferential spacings 104 between projections 102 are provided. The 
projections 102 and the spacings 104 cooperate, as explained subsequently, 
so that the actuation tool may be mechanically interconnected to the valve 
collar 86, but also allow the actuation tool 20 to be rotated and moved 
axially past the valve collar 86 and through the inflatable packer 10 for 
actuating another inflatable packer positioned along the casing string C 
either above or below the packer 10. 
The lower end 14 of the inflatable packer 10 is functionally equivalent to 
various types of inflatable packers, and accordingly is only generally 
shown in FIG. 1B. The lower end of the inner tube 74 is interconnected 
with the sub 110 by threads 112 or other conventional securing members. 
O-ring seal 111 and metal-to-metal seal 113 provide for reliable sealing 
between inner tube 74 and sub 110. The lower end of sub 110 is in threaded 
engagement with mandrel 116 which extends axially downward to a position 
below the elastomeric packer element 120. The lower end of the mandrel 116 
includes conventional threads 18 for threaded engagement with the casing 
C. Accordingly, the sub 70, the inner tube 74, the sub 110, and the 
mandrel 116 provide a structural interconnection between the casing string 
above the packer 10 and the casing string below the packer 10. 
The annular passageway 76 as shown in FIG. 2 thus continues downward 
between the sub 110 and the outer tube 72. This flow passageway then 
extends radially inward between the mandrel 116 and the upper packer sub 
118, then into the inflation chamber between the packer element 120 and 
the mandrel 116. The upper packer sub 118 is threadably connected to the 
lower end of the outer tube 72 by conventional threads 115, and is sealed 
to the outer tube by an o-ring seal 117. For the embodiment as shown 
herein, the upper sub 118 is thus axially fixed with respect to the casing 
C. A lower packer sub 122 is provided at the lower end of the elastomeric 
packer element 120, and includes a seal 124 for dynamic sealing engagement 
with the outer surface of the mandrel 116. During inflation of the packer, 
the lower packer sub 122 may move axially upward toward the upper packer 
sub 118 to accommodate expansion of the elastomeric packer element 120. 
Cementatious fluid typically includes particles which tends to plug small 
valves or passageways with small diameters. Also, cementatious fluid which 
is pumped at high velocities through small valves and small diameter 
passageways corrodes the valves and passageway walls during the inflation 
process. These problems are thus avoided by providing one or more large 
diameter inlet ports 94 and an annular passageway 76 fluidly connecting 
the inlet ports 94 with the packer inflation chamber. According to the 
present invention, the flow through area of the one or more inlet ports 94 
is at least 0.15 square inches, and preferably is at least 0.25 square 
inches. A cement slurry with solid particles will thus reliably pass 
through the inlet ports 94 and the annular passageway 76 and then to the 
packer inflation chamber without plugging the flow path. 
When inflation packers are set by plugging operations as discussed above, 
the well operator may be unsure which packer is being inflated. According 
to the present invention, the actuating tool 20 at the end of work string 
WS is used to open and close the valve collar 86. Accordingly, the payout 
length of work string WS may be used to reliably determine which packer 
positioned along the casing string is being acted upon by the tool 20 to 
open and close the valve collar. If desired, a conventional locator sub 
may also be run in with the actuating tool 20 to further ensure the 
position of the tool 20 within the well and thus the reliable operation of 
the desired inflatable packer. 
The actuating tool 20 includes one or more locking dogs 58 which are biased 
radially outward by springs 62. The dogs 58 may thus move radially 
relative to the actuator body, and together define an exterior profile for 
locked engagement with the valve collar 86. The radially inward surface of 
the valve collar 86 thus includes spaced apart grooves 96 and 98 separated 
by a partial ring or flange 102 having upper and lower stop surfaces 
thereon. The dogs 58 thus fit within a respective groove 96, 98 to mate 
with the valve collar 86 so that axial forces may be reliably transmitted 
from the work string WS to a tool 20 and then to the valve collar 86 to 
open and close the collar. The spring biased dogs 58 also provide a 
positive indication that the tool 20 is mechanically interconnected with 
the valve collar. Separate upper and lower dogs may be provided, or upper 
and lower dogs on a unitary component 58 may be separated by groove 60 
which fits within partial flange 102. 
When a tool 20 is interconnected to the valve collar 86, the upper seal 
cups 42 and the lower seal cups 54 will sealingly engage the packer body. 
When the tool 20 is interconnected with the valve collar 86, the operator 
may slack off the work string WS, thereby allowing gravity and compressive 
loads (weight of the WS) to drop the tool 20 and thus simultaneously lower 
the valve collar 86 to the opened position and open the sliding valve 50 
internal of actuator body so that ports 51 are in fluid communication with 
ports 52. Cementatious fluid from the bore in the work string WS may then 
be pumped through the work string WS so that the cementatious fluid flows 
through ports 51 in sliding valve 50 and through ports 52 in actuator 
body, then into the open port 94 in sleeve 74 and down the annular 
passageway 74 to inflate the packer element 120. Since fluid pressure is 
not required in the annulus between the work string WS and the casing C, 
this inflation operation may be accomplished even if the casing string 
above the packer is slotted or perforated. 
Once the packer 10 is inflated, the operator may pull up on the work string 
WS, thereby raising the tool 20 and returning the valve collar 86 to the 
closed position. During this upward pull, a tensile applied to the work 
string WS will make up the metal-to-metal seals between the valve collar 
and the work string, as shown in FIG. 3. The packer body thus includes a 
tapered upper metal sealing surface 136 and a tapered lower metal sealing 
surface 132 each formed at a relatively low angle relative to the axis of 
the packer body. The valve collar 86 includes corresponding tapered upper 
and lower metal sealing surfaces 134 and 130. The sealing forces used to 
reliably make up the metal-to-metal seals may be controlled by regulating 
the upward pull on the work string WS and by maintaining a desired cam 
angle between the tapered metal-to-metal sealing surfaces. 
After the operator pulls up on the work string WS to close the valve 86, 
fluid pressure may be increased on the bore of the work string WS to 
reliably test the integrity of the closed valve collar. If there is any 
leakage between the closed valve collar and the packer body, fluid 
pressure in the work string will slowly decrease. In that event, the 
operator may slack off the work string to at least partially open the 
valve collar 86, then again pull up on the work string with a higher 
tensile force to form a more effective metal-to-metal seal between the 
valve collar and the packer body. The relatively high forces transmitted 
through the work string to the valve collar when forming the 
metal-to-metal seal may result in a minimal amount of metal deformation or 
galling of these metal sealing surfaces. This galling is not undesirable, 
however, since this action may be used to practically ensure that the 
valve collar 86, once reliably closed, will not inadvertently thereafter 
open after the actuating tool 20 is moved to a new location in the well. 
The use of metal-to-metal seals between the valve collar and the packer 
body is highly desirable for the long term reliability of the inflated 
packer to ensure that well fluids which normally deteriorate elastomeric 
seals cannot enter the interior of the inflation chamber. It should be 
understood, however, that elastomeric upper annular seal 90 and 
elastomeric lower annular seal 92 may also be provided for sealing between 
the valve collar and the packer body. These elastomeric seals provide for 
redundant sealing, and effectively prevent well fluids from initially 
contaminating the metal-to-metal sealing surfaces. Over an extended period 
of time and after the cementatious fluid in the set packer is cured, the 
well fluids may attack and effectively destroy the sealing effectiveness 
of the elastomeric seals. Well fluids passing by the elastomeric seals 90 
and 92 will not be able to enter the inflation chamber, however, because 
the reliable metal-to-metal seals are provided fluidly downstream from the 
elastomeric seals. 
As previously noted, the partial ring or flange 102 does not extend 
circumferentially completely about the valve collar. The spacing 104 
between ring segments allows an operator to selectively engage the locking 
dogs 58 with the valve collar 86, or alternatively to pass the tool 20 
vertically upward or downward past one inflatable packer for reliable 
actuation of either an upper or a lower inflatable packer. As previously 
indicated, the biased dogs 58 allow the well operator to reliably 
determine if the dogs 58 have locked onto a particular valve collar 86. If 
locking engagement between the dogs 58 and that valve collar is not 
desired, the operator may rotate the work string WS and thus the tool 20 
and the locking dogs 58 so that the locking dogs 58 are circumferentially 
positioned in line with spacing 104. With the dogs 58 circumferentially 
aligned with the spacings 104, tool 20 may be easily passed by the valve 
collar of one inflatable packer and then repositioned for engagement with 
a similar valve collar of another inflatable packer positioned along the 
casing string. In this manner, any number of inflatable packers positioned 
along a casing string may be selectively actuated to open and close the 
inflation chambers with a single trip of the work string WS within the 
well. 
Once a particular valve collar 86 is opened and cementatious fluid is 
pumped into the inflation chamber to inflate the desired packer, the valve 
collar 86 may then be mechanically returned to the closed position, as 
described above. Once closed, the operator may reliably remove excess 
cementatious fluid within the work string WS by a reverse circulating 
operation. During this process, fluid pressure is increased in the annulus 
between the work string WS and the casing C. This increased fluid pressure 
will enter the interior of the tool 20 (valve 50 is still open), thereby 
forcing the excess cementatious fluid in the bore of the work string WS 
upward to the surface. The excess cementatious fluid may thus be reverse 
circulated to the surface in a simple and reliable manner. Most 
importantly, drill out of plugs and excess cementatious fluid is not 
required. The high cost and numerous problems which conventionally 
accompany drill out operations may thus be avoided according to the 
technique of the present invention. 
Various modifications to the inflatable packer and to the technique as 
described above may be made without departing from the concepts of the 
present invention. If desired, for example, an actuating tool may include 
dogs with a profile for mated engagement with only selected ones of 
various valve collars associated with inflatable packers positioned within 
a well, thereby ensuring that the actuating tool will always pass by a 
valve collar with a profile which is not intended for mating engagement 
with that actuating tool. The packer body on which the port collar is 
mounted may be provided with a locator sub for ensuring the position of 
the port collar and/or the packer within the well. While the present 
invention has particularly described for the application wherein the 
packer is inflated with a cementatious fluid which then cures and hardens 
within the well, those skilled in the art will appreciate that the 
concepts of the present invention may also be applied for inflating a 
packer with any type of inflation fluid. 
In the embodiment discussed above, the valve collar 86 is positioned 
axially above the elastomeric packer element 120. The valve collar 86 
could, however, be spaced axially below the packer element. As previously 
noted, the valve collar could also be opened and closed in response to 
rotation. Mechanical forces transmitted through the work string to an 
actuating tool may thus result in sufficient torque applied to the valve 
collar to open and close the valve collar. Axial forces transmitted 
through the work string to the actuating tool may still be used, if 
desired, to reliably make up a metal-to-metal seal between the valve 
collar and the packer body. 
The port collar as disclosed herein may also be operated by an actuating 
tool to selectively pump a cementatious fluid from a work string through 
the casing and then into an annulus about the casing. The metal-to-metal 
seal as disclosed herein would then desirably be formed between the valve 
collar and a mandrel positioned along the casing string and supporting the 
port collar. In some applications, an inflatable packer will thus not be 
necessary to form a reliable downhole cementatious plug. 
The foregoing disclosure and description of the invention is illustrative 
and explanatory thereof, and it will be appreciated by those skilled in 
the art that various changes in the size, shape and materials as well as 
in the details of the illustrated construction or combinations of features 
of the various inflatable packer elements and the method of actuating a 
packer and removing excess cementatious fluid from the interior of the 
work string WS discussed herein may be made without departing from the 
spirit of the invention.