Wells – Processes – Operating valve – closure – or changeable restrictor in a well
Reexamination Certificate
1999-09-01
2001-08-14
Bagnell, David (Department: 3672)
Wells
Processes
Operating valve, closure, or changeable restrictor in a well
C166S387000, C166S129000, C166S320000, C166S326000
Reexamination Certificate
active
06273195
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to generally to the control of fluid flow in piping systems. More specifically, this invention relates to control valves and systems for controlling the flow direction, flow rate and flow pressure of a fluid in a piping system, such as a subterranean well.
BACKGROUND OF THE INVENTION
One type of valve used to control fluid flow in subterranean wells is known as an inflatable packer. In its simplest form a packer valve includes a pressure element adapted to sealingly engage, or disengage, a conduit of the well, such as a pipe or bore hole, to prevent, or to allow, fluid flow through the conduit. This allows a portion of a well to be isolated for sampling, flow testing, cementing, and other operations.
Inflatable packers can also include an internal mandrel configured as a conduit for pumping fluids out of the well, or for injecting fluids into the well. One application in which water is injected into a water well is known as Aquifer Storage and Recovery (ASR). Recharge water wells are used in ASR programs to assist communities during times of peak water demand. The ASR process involves injecting treated water through recharge wells into under ground aquifers during low-demand time periods, such as the winter months. The treated water can then be recovered using the recharge wells during high-demand time periods, such as the summer months.
A packer valve configured to control flow and pressure during injection of a fluid into a well is disclosed in U.S. Pat. No. 5,316,081 to Baski et al., entitled “Flow And Pressure Control Packer Valve”.
FIG. 1
from the above patent illustrates the prior art control valve
10
within a well
12
. The control valve
10
is in fluid communication with a submersible pump
14
powered by a motor
16
. In addition, the control valve
10
is in flow communication with a pump pipe
18
and with surface piping
20
.
FIGS. 2A and 2B
illustrate the operation of the control valve
10
during injection of water into the well
12
. In
FIG. 2A
an inflatable element
22
of the valve
10
can be deflated to allow water injection from the surface, as indicated by flow arrows
24
. The water is injected through a sand trap
28
, and into an annular area
30
located between the uninflated surface of the inflatable element
22
, and the inside diameter of an external housing
32
of the valve
10
. The external housing
32
also includes a series of annular grooves
34
formed on the inside diameter thereof. The annular grooves
34
are configured to increase a frictional pressure loss through the valve
10
during injection, so that the injected water does not cascade and cavitate as it flows through the annular area
30
into the well
12
. The annular grooves
34
can be configured to provide a desired frictional pressure loss, and thus a desired fluid pressure within the annular area
30
. In addition, the inflatable element
22
can be pressurized to partially expand into the annular area
30
, increasing pressure loss and reducing (controlling) flow through the valve.
In
FIG. 2B
, inflation of the inflatable element
22
seals the annular area
30
so that water cannot be injected into the well
12
. However in this mode, water can be pumped from the well
12
through the check valve
26
, and through an internal mandrel
36
of the valve
10
to the surface, as indicated by flow arrows
38
.
The prior art control valve
10
is effective for controlling flow direction and fluid pressure of a fluid during injection into the well
12
. However, one shortcoming of the valve
10
is that it is expensive to manufacture. In particular, the annular grooves
34
are difficult to machine on the inside diameter of the external housing
32
. Typically, the grooves
34
must be machined on relatively short lengths of pipe, which must then be welded together to produce an external housing
32
with the required length.
The present invention is directed to a control valve that can also be utilized to control the flow direction and fluid pressure of a fluid during injection into a well. However, the control valve of the invention can be more easily manufactured, made with fewer parts, and is more effective in controlling fluid pressure over a wider range of well sizes than prior art control valves. The present invention is also more dependable, being much more difficult to sand lock, and not having exposed inflation tubes to break or malfunction.
SUMMARY OF THE INVENTION
In accordance with the present invention, an improved flow and pressure control valve is provided. In an illustrative embodiment the valve is configured for controlling fluid flow in a subterranean well. However, the valve can also be used to control fluid flow in any piping system, including above ground systems. Also provided are an improved well system that includes the control valve, and an improved method for injecting fluids into wells performed using the control valve.
The control valve can be used in a pumping mode to control the flow direction of a fluid during pumping of the fluid from the well. The control valve can also be used in an injection mode to control the flow direction, flow rate and flow pressure of the fluid during injection of the fluid into the well. In the injection mode, the valve is constructed to produce a frictional pressure loss as the fluid flows through the valve. The frictional pressure loss can be adjusted by control of a pressure element of the valve from the surface, to provide a desired flow rate and flow pressure in the fluid, and to prevent cavitation and cascading of the fluid.
The control valve includes an outer housing and an elongated mandrel located within the outer housing. The mandrel forms a conduit in flow communication with surface piping at an uphole end of the valve, and in flow communication with a submersible pump at a downhole end of the valve. For submersible pump applications, the mandrel includes a check valve proximate to the downhole end of the valve. During the pumping mode, fluid can be directed through the check valve, and through the mandrel to the surface piping. The control valve can also be used with turbine pumps, rather than submersible pumps, or without pumps, for control of injection only.
The control valve also includes the pressure element, which is connected to the inside diameter of the outer housing, and an annular flow passage located between the pressure element and an outside diameter of the mandrel. The pressure element comprises a multi-ply, vulcanized elastomeric tube, reinforced with strands of a reinforcing material, such as synthetic cords of polyester, aramid, nylon, or rayon; or steel cables. The pressure element is configured to seal the flow passage during the pumping mode, or alternately to vary an area of the flow passage during the injection mode.
A pressure chamber proximate to the uphole end of the valve contains a pressurized fluid for pressurizing the pressure element. The pressure chamber is controlled by gas pressure from the surface, and is in flow communication with an annular pressure passage located between the outer housing and the pressure element. A longitudinally extending vent tube is attached to the outer housing within the pressure passage, and includes vent holes for equalizing fluid pressure applied along the length of the pressure element, preventing inflation fluid from being trapped in the pressure passage.
The flow passage is in flow communication with the mandrel via radial flow orifices formed through the sidewall of the mandrel. The flow passage is also in flow communication with the well via a discharge annulus between the outer housing and the mandrel. An orifice section of the mandrel includes annular orifices which comprise annular grooves on the outside diameter thereof, and channel elements which comprise u-shaped channels attached to the outside diameter thereof. The annular orifices and channel segments form a frictional surface, and provide tortuous, axial, and circumferential flow paths through the flow passage, during the inj
Baski Henry A.
Hauck Emil
Bagnell David
Baski Water Instruments, Inc.
Gratton Stephen A.
Hawkins Jennifer M.
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