Well system

Disclosed is a well system, particularly adapted to pumpdown operation in which lowering an easily retrievable tool string, including an improved standing valve, into an improved foot valve opens the foot valve for production flow. The standing valve prevents flow into the producing formation when the foot valve is open. Lifting the tool string from the foot valve closes the foot valve to protect the producing formation when the tool string is retrieved. Means are provided retaining the foot valve in open or closed positions. Provisions are made for pumping into the formation around both the standing valve and foot valve when closed.

BACKGROUND 
This invention relates to well systems particularly adapted for pumpdown 
operation, and an improved standing valve for use in a retrievable tool 
string, which cooperates with an improved foot valve, to protect the 
producing formation from pressure on or flow into during operation of the 
well. 
It is often imperative during well completion and operation, especially if 
the well is operated using pumpdown or through-flow-line and pumpdown 
techniques, to protect the producing formation from overpressuring or 
pumping appreciable volumes into to prevent damage to or kill the 
formation. 
Formation protection is provided by the Well System of U.S. Pat. No. 
4,365,671 to Olen R. Long, herein incorporated for reference, but the tool 
string has been found difficult, if not impossible to pump out and 
retrieve because of down forces on the tool string being almost equal to 
up forces developed as pumpout pressure is applied through the H-member 
cross flow passage between locomotive pistons and the standing valve seal 
to retrieve the tool string. The locomotive pistons and standing valve 
seal have very nearly the same sealed area, and pressure introduced 
between these seals merely places the tool string in tension, and it is 
not strongly urged to move up tubing and close the foot valve. 
Additionally, when the ball valve member in the foot valve of the 
aforementioned U.S. patent is closed, higher pressures below produce 
greater upward forces, on the piston sealed in the lower body and on the 
seat, sealed in the piston, tending to crush the valve ball member. These 
upward forces also press the seat on the ball, greatly increasing rubbing 
friction forces which induce high stresses in the ball rotating mechanism 
when opening the foot valve. If these upward forces become great enough, 
the shear pin positioning the piston on the seat may be prematurely 
sheared and fluids may inadvertently bypass the closed foot valve and flow 
into the formation below, with severely damaging results. 
SUMMARY 
The well system of the present invention prevents pressuring of or pumping 
into the producing formation in a well. An improved foot valve in the 
producing string controls flow from and into the producing formation. An 
improved standing valve in a tool string, which operates the foot valve, 
prevents flow into the formation through the foot valve when the foot 
valve is opened to produce the well. Both valves may be bypassed if 
pumping into the formation is ever required. The operating tool string 
includes an improved extendable standing valve, attached to the lower end 
of the string, and an Improved Shifting Tool of copending U.S. patent 
application Ser. No. 422,739 filed Sept. 24, 1982 now U.S. Pat. No. 
4,436,152. The tool string may include a locking mandrel. 
The extendable standing valve has a lower housing with a seal and an 
extendable upper body with a seal. Both seals seal in the foot valve upper 
seat extension when the tool string is installed in and opens a 
cooperating foot valve in the invention system. When pumpout pressure is 
applied to the system to pump the tool string out and close the foot 
valve, pressure is transmitted to between the standing valve body seals. 
As the lower body is landed on a shoulder in the foot valve extension and 
is not moved downwardly by pressure, the upper body seal is moved 
upwardly, extending the standing valve body, moving the shifting tool 
upwardly and closing the foot valve. 
The improved foot valve utilizes a spring to maintain a force upward on the 
lower seat for constant sealing engagement with the ball valve member. 
Unlike previous foot valves, higher pressures below the closed invention 
foot valve produce greatly reduced upward forces pressing the lower seat 
to the ball valve. Any upward forces on the piston are transmitted into a 
shoulder in the body and do not move the piston and seat upwardly or load 
the piston positioning pin in shear. 
An object of this invention is to provide an improved well system 
preventing flow into the producing formation in a well. 
Another object of this invention is to provide an improved well foot valve 
which is easily opened when higher pressure is below. 
Another object of this invention is to provide a well foot valve which 
cannot be opened by higher pressure below. 
Another object of this invention is to provide a tool string, cooperable 
with the improved foot valve, and including an improved standing valve, 
which will open the foot valve for production flow when installed and 
close the foot valve to protect the producing formation when removed. 
Another object of the invention is to provide an improved standing valve, 
which cooperates with the improved foot valve to provide positive up 
forces to move the tool string up and out of the foot valve as pumpout 
pressure is applied in the well system. 
Also an object of this invention is to provide a foot valve having means 
retaining the valve open or closed.

PREFERRED EMBODIMENT DESCRIPTION 
The invention well system 10 shown in FIG. 1 includes casing 11 passing 
through a producing formation 12. The casing has perforations 13 through 
which production fluids drain into the casing. Dual tubing strings 14 and 
15 pass through a dual packer 16 set in the casing and the lower end of 
tubing 14 is closed. An H-member 17, with cross flow passage 18, is 
included in the tubing strings below the packer. Below the H-member in 
tubing string 15 is a foot valve 19 of this invention. 
The foot valve is operated by a tool string 20, FIG. 2, which includes an 
extendable standing valve 21 of this invention connected with sealed 
swivel connector 22 to an improved shifting tool 23 of the previously 
mentioned copending U.S. application, which may be connected with another 
connector 22 to an appropriate locking mandrel 24. The foot valve and 
invention well system may be operated without a locking mandrel in the 
tool string. The locking mandrel is useful to lock the preferred 
embodiment tool string in the open foot valve to prevent production flow 
from prematurely lifting the tool string, closing the foot valve and 
stopping production. 
If a locking mandrel is included in the tool string, a running tool and 
pump down piston are connected above. If the locking mandrel is not used, 
the pump down pistons are connected above the shifting tool. 
The foot valve 19, FIG. 2, has an appropriate connection on the upper end 
of upper body 25 for connection in well tubing. This upper body is 
provided with profiled grooving 26 therein, for engagement by a locking 
mandrel. There is a seal bore immediately below grooving 26 for sealing 
engagement with any seal on a locking mandrel engaging this grooving. 
Housed in a bore near the lower end of the upper body is an expandable 
c-ring 27, with spacer rings 28 above and below. The spacer rings are 
useful in positioning the c-ring slightly upward or downward as required 
for proper operation. 
Connected to the lower end of the upper body with an appropriate thread 29 
is a body connector 30. Intermediate body 31 is connected to the lower end 
of the connector by another appropriate thread 29. Body 31 is provided 
with an internal shoulder 32. Housed for reciprocating movement in the 
foot valve is an actuator 33, the lower end of which receives pivots 34 
having pins 35 extending into holes in the sides of ball valve member 36 
(FIG. 3). Downward movement of the actuator rotates the ball valve to open 
position, and upward actuator movement rotates the ball to closed 
position. In the upper end of actuator 33 is profiled grooving 37 
engageable by a shifting tool. The actuator has external shoulders 38, 
both shoulders having upward and downward tapered portions and slots 39 
providing flow passages through. The actuator also has a flow port 39a and 
lower flow slot 39b. 
Slidably mounted in the actuator is an upper annular seat 40, which rests 
on the valve ball but does not seal with it. Mounted for reciprocating 
movement in the actuator and resting on the upper seat is an extention 41 
having an internal shoulder 42 and a seal bore 43. Clearance between the 
outside of extension 41 and the inside of actuator 33, provides an annular 
flow passage 44, and a port 45 is provided through the wall of actuator 
33. 
Slidably mounted in intermediate body bore 46 below shoulder 32 is a piston 
47, sealed in the bore with resilient seal 48 and positioned by shear pins 
49 through holes in sleeve 50 protruding into a piston groove. 
A lower annular seat 51 is maintained in sealing contact with ball valve 36 
by spring 52 biasing the lower seat extension 53 and lower seat upwardly. 
Piston 47 is slidably sealed to seat 51 with upper resilient seal 54 and 
slidably sealed to extension 53 with lower resilient seal 55. The lower 
seat extension has flow slots 56 in the upper end and an intermediate 
external shoulder 57. 
Connected to the lower end of body 31 with an appropriate thread 58 is 
lower body 59, having an appropriate thread 60 for connection in tubing. 
The extendable standing valve 21 of this invention, as seen in the 
preferred form in FIG. 2, has a connector cap 61 and jam nut 62 threaded 
onto the upper end of upper body 63 for connection to a tool string. The 
upper body is threaded onto mandrel 64, retaining resilient seal 65 and is 
sealed to the mandrel with resilient seal 66. In the lower end of mandrel 
64 is a flow slot 64a connecting into an internal flow slot 64b. 
The mandrel is slidably disposed around extension 67 and retained in the 
unextended position by shearable screw 68, threaded through mandrel 64 and 
protruding into holes in the extension. The extension is connected to 
lower valve body 69 with threads 70 and has ports 71 through the extension 
wall. The extendable standing valve may also take the form of having a 
connector 22 connecting extension 67 and body 69, in place of thread 70. 
Mounted on the body 69 is a resilient seal 72 retained by retaining ring 73 
in a groove in the lower body. Mounted on the body above the retaining 
ring is a retainer 74, a wear ring 75 and a ring 76, retained by an upper 
retaining ring 73 in another groove in the lower body. The wear ring is 
made slightly larger than resilient seals 72 and 65 and is cut to form a 
c-ring. The wear ring centralizes the resilient seals when running down 
tubing, preventing abrasive wear on the seals. The outside diameter of the 
cut wear ring may be biased smaller and reduced to less than the diameter 
of the adjacent resilient seals. 
Slidably housed in a bore in the lower body is a sleeve 77 having an 
internal shoulder 78 and slots through its wall. Also slidably housed, 
partially in a lower body bore and partially in a bore in guide 79, is a 
seat 80, on which ball 81 is seated by gravity, preventing down flow 
through the standing valve. Guide 79 is connected to the lower body with 
thread 82. The guide has ports 83 through its wall and an internal 
shoulder 84. 
Seat 80, when positioned up by shearable screws 85, is sealed in lower 
valve body by resilient seal 86. Screws 85 are threaded through the wall 
of guide 79 and protrude into a groove in the lower end of the annular 
seat. 
To operate the well system of this invention, component parts should be 
installed in a well as shown in FIG. 1, with the foot valve 19 closed, 
preventing down flow. To open the foot valve and the well for production 
flow, a tool string 20, with standing valve 21 not extended, is lowered 
through tubing into the foot valve. The tool string may be pumped down or 
lowered on wireline. 
As the tool string shifting tool 23 enters the foot valve, the shifting 
tool keys engage the profiled grooving 37 in actuator 33. Continued 
downward movement of the tool string and actuator, rotates the valve ball 
36, through pivots 34 and pins 35, to foot valve open position. Standing 
valve seals 65 and 72 are positioned and sealing in bore 43 in extension 
41. The seal on locking mandrel 24, if included in the tool string, is 
positioned and sealing in the seal bore below grooving 26 and the locking 
mandrel may be operated to lock in grooving 26, locking the tool string in 
and the foot valve open as seen in FIG. 2. 
As the actuator moved downwardly, lower shoulder 38 expanded c-ring 27 and 
moved fom above to below the c-ring, and the c-ring recontracted between 
upper and lower shoulders 38. The contracted c-ring alone will retain the 
actuator down and foot valve open if the tool string does not include a 
locking mandrel. 
Production flow may now occur up through the open foot valve and tool 
string, lifting and flowing around standing valve ball 81. Ball 81, seated 
by gravity and pressure from above on seat 80, will prevent flow down 
through the open foot valve into the producing formation 12. 
When the tool string is pumped down into and opens the foot valve, the pump 
down pistons remain in tubing 15 above the H-member to be later pumped 
out. When it is desired to pump the tool string out and close the foot 
valve, pressure is applied to tubing string 14 down through the H-member 
cross flow 18 and up under the tool string pistons. This pumpout pressure 
is also transmitted down inside the tool string through standing valve 
extension ports 71 and mandrel slots 64b and 64a into upper seat extension 
bore 43 between resilient seals 65 and 72. Shoulder 42 prevents pump out 
pressure down on seal 72 and seated ball 81 from moving lower valve body 
69 down. Increased pumpout pressure acts upwardly on seal 65, and the tool 
string pistons above, to shear pins 68 and move upper body 63, mandrel 64, 
shifting tool 23 and actuator 33 upwardly, extending the standing valve, 
rotating ball 36 to close the foot valve, and unlocking locking mandrel 24 
if used. When lower shoulder 38 has expanded and moved through to above 
c-ring 27, the ball has rotated fully closing the foot valve, and the 
standing valve has extended so that seal 65 is out of extension bore 43, 
as shown in FIG. 4B. 
Pumpout fluids may now flow from inside the tool string out through ports 
71 by seal 65 down through annular clearance 44 and in port 45 equalizing 
pressures above and below valve ball 81. 
Further upward movement of the tool string automatically disengages the 
tool string shifting tool 23 from the actuator profiled grooving 37, 
releasing the tool string to be pumped back to surface. The closed foot 
valve prevents pressure on or flow into producing formation 12. 
The c-ring, contracted below lower shoulder 38, retains the actuator in up 
foot valve closed position. 
Both the standing valve and foot valve of this invention may be pressured 
sufficiently from above and positioned for down flow around into the 
producing formation as shown by FIG. 5. 
When the standing valve is sealed in extension seal bore 43, sufficient 
pressure applied on seated standing valve ball 81 will shear screws 85 and 
move seat 80 down from sealing engagement in resilient seal 86. Down flow 
from inside the tool string through slots in sleeve 77 and ports 83 may 
now occur, bypassing valve ball 81 seated on seat 80. 
When pressure is applied on closed foot valve ball 36 and piston 47, 
through clearance 44, port 45 and flow passages 39a and 39b, piston 47 is 
moved downwardly, compressing spring 52, until shoulder 57 on extension 53 
contacts the upper end of lower body 59. Sufficient down pressure to shear 
pins 49, will move piston 47 further down, positioning resilient seals 54 
and 48 below extension slots 56. Down flow through the foot valve around 
closed valve ball 36 sealing on seat 51 may now occur through slots 56.