1. Field of the Invention
This invention relates in general to oil and gas production, and in particular to a multi-ported flow regulator used for injecting fluid into a wellbore.
2. Description of Related Art
Oil and gas production involves extracting hydrocarbons from a subterranean formation in which they are entrained. The hydrocarbons, either in liquid (oil) or gas form, flow to the surface within a wellbore that intersects the formation. Other fluids, such as water, CO2, N2, and H2S, may be included in the formation with the hydrocarbons. An injection fluid, which is typically different from the produced fluid, is sometimes used during the production of fluids from subterranean formations. The injection fluid(s) can be added at a wellhead mounted on top of the wellbore, within the wellbore, or into the formation, the injection location depends on why the injection fluid is being used.
Often, the fluids that are injected into the formation or deep in the wellbore are to enhance production. For example, a lower viscosity fluid can be injected into the produced fluid, in the formation or production tubing in the wellbore, to decrease the viscosity of the fluid being produced and reduce flow drag. A lower density fluid can be injected to reduce production fluid density thereby increasing its flow rate. Injection fluids can also be used to treat the formation for enhancing flow. Certain injection fluids can etch the formation and increase flow capacity through pores in the formation. Other injection fluids can aid in the separation of polar and non-polar compounds and aid in the extraction of the produced fluids from the formation. Formation pressure can be maintained or increased by injecting a higher pressure fluid into the formation. In some instances, increasing formation pressure can enhance flow of produced fluids from the formation. Examples of injection fluids include rust inhibitors, chemical treatments, surfactants, steam, water, grease, natural gas, brine, and alcohol.
Fluid injection may occur at more than one location in the well, where the different locations are at different pressures. Additionally, the flow rate of fluid injection at each location may differ. Individual supply lines may be provided that extend from the surface directly to each injection point. This may be problematic due to space limitations within the wellbore and at the wellhead.
Disclosed herein is a method of injecting fluid into a well that includes isolating first and second formations in a well from one another, extending conduit from a wellhead assembly into the well, the conduit having a first port in fluid communication with the first formation and a second port in fluid communication with the second formation, pumping fluid down the conduit and to the ports, and controlling flow through each of the ports so that the flow rates through each of the ports is substantially constant as the pressure difference between the conduit and the first and second formations vary. Fluid discharged from the first port and from the second port can be at different pressures. Each port can have a flow control device with a variable flow area that varies in inverse proportion to the pressure in the conduit. The method can further include setting a packer between the first and second formations as well as mounting a flow control device in each of the ports on the exterior of the conduit. The injection fluid can be acid, water, steam, gas, brine, surfactants, rust inhibitors, scale treatment fluids, alcohol, or combinations thereof. In one example, the injection fluid is maintained at a subcritical condition.
A fluid injection system for injection into a subterranean well is also described herein. In one example the fluid injection system includes a fluid source, a fluid supply line in fluid communication with the fluid source, a first flow control regulator in fluid communication with the fluid supply line and having a discharge in pressure communication with a first location within subterranean well, so that when the fluid source supplies fluid to the fluid supply line, the fluid exits from the discharge to the first location within the subterranean well at a constant flow rate, and a second flow control regulator in fluid communication with the fluid supply line and having a discharge in pressure communication with a second location within the subterranean well that has a pressure different from the first location, so that when the fluid source supplies fluid to the fluid supply line, the fluid exits from the discharge to the second location within the subterranean well at a constant flow rate. The location in the subterranean well can include a wellhead housing, a production tree, an annulus between wellbore tubulars, and within production tubing. The fluid can exit from the discharge at a constant flow rate over a range of pressures in the fluid supply line and the locations in the subterranean well. The flow control regulators can include a flow path with a selectively changeable flow area. In an alternative example, the flow control device has an inlet, a fixed sleeve in fluid communication with the inlet, a fixed port formed through a side of the fixed sleeve, a floating sleeve coaxial and slidable with respect to the fixed sleeve, a floating port formed through a side of the floating sleeve and selectively registerable with the fixed port, a restriction orifice on an end of the floating sleeve in fluid communication with the floating port, and a compressible resilient member in contact with the restriction orifice on a side of the restriction orifice opposite the fixed sleeve, so that when injection fluid is directed to the inlet of the flow control device, the fluid flows to the fixed sleeve, through the registered fixed and floating ports, and through the restriction orifice to generate a pressure differential across the restriction orifice that creates a force to slide the floating sleeve away from the fixed sleeve misalign the floating port and fixed port that in turn reduces the flow area through the flow control device. The injection fluid can be acid, water, steam, gas, brine, surfactants, rust inhibitors, scale treatment fluids, alcohol, or combinations thereof.
Included with the present disclosure is a method of treating a well assembly with an injection fluid that includes providing a constant flow valve made up of, an inlet, a discharge, a flow path between the inlet and discharge, a passage in the flow path, a slidable sleeve having a side wall adjacent and normal to the passage, an orifice in the flow path attached to an end of the slidable sleeve, so that when fluid flows through the orifice a resultant force is produced that can slide the sleeve in a first direction that moves the side wall of the sleeve over a portion of the passage. The method of this embodiment further includes applying a limiting force on the sleeve in a second direction that is opposite the first direction, providing fluid communication between the discharge and a location in the well assembly, and delivering a pre-selected amount of injection fluid to the well assembly and at a substantially constant flow rate by supplying an injection fluid to the inlet
Some of the features and benefits of the present disclosure having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which:
While the subject device and method will be described in connection with the preferred embodiments but not limited thereto. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the present disclosure as defined by the appended claims.
The method and system of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. The method and system of the present disclosure may be in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be through and complete, and will fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout.
It is to be further understood that the scope of the present disclosure is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation. Accordingly, the improvements herein described are therefore to be limited only by the scope of the appended claims.
A partial section view of the flow regulator 10 is shown in perspective view in
An alternate example of a constant flow valve 24A is shown in a side sectional view in
The floating orifice 62 includes an orifice element 72 shown disposed downstream of the ports 68 within the discharge annulus 63. A spring 74 is coaxially disposed in the discharge annulus 63 shown partially circumscribed by a forward sleeve 76 extending axially from the orifice 72 and away from the inlet 56. The discharge annulus 63 includes an outlet 78 at its end opposite the fixed sleeve 58. One end of the spring 74 contacts the downstream side of the orifice 72 and the other end of the spring 74 contacts a flange 80 shown projecting radially inward from the body 54 adjacent the outlet 78.
In one example of use, fluid that enters the flow regulator 10A is directed to the inlet 56 and to within the fixed sleeve 58. From the fixed sleeve 58 the fluid can flow through the registered ports 60, 66, the annulus 70, and the ports 68 and into the discharge annulus 63. Within the discharge annulus 63, the fluid flows through the restricted diameter orifice 72 before exiting the constant flow valve 24A. Restricting flow through the orifice 72 creates a pressure differential across the orifice 72 that translates into a force to urge the floating orifice 62 downstream and compress the spring 74. As the floating orifice 62 is moved downstream, the ports 60, 66 become misaligned thereby reducing the effective flow area through the valve 24A. The reduced flow area reduces flow through the ports 60, 66 that in turn decreases the pressure differential across the orifice 72. When the pressure drop across the orifice 72 and spring force are substantially the same the floating orifice 62 will stabilize and cease to move thereby maintaining a constant flow rate of fluid through the constant flow valve 24A.
An alternative constant flow control device is illustrated in a schematic view in
With reference now to
Examples of pressure regulators 10 are shown disposed within the wellbore 3 at multiple locations. The regulators 10 may be threadingly connected to a base 11 shown within the annulus 7. An injection line 46 for transporting an injection fluid or fluids is illustrated that conveys injection fluid from an injection fluid source 45 to the production tree 42. The injection line 46 can optionally include a flow meter 47 between the source 45 and the production tree 42. The end of the injection line 46 opposite the fluid source is shown connected to an injection port 44 mounted in the production tree 42. Examples of injection fluid include acid, water, steam, gas, brine, surfactants, rust inhibitors, scale treatment fluids, alcohol, and combinations thereof, to name but a few. An injection fluid supply line 50 in fluid communication with the injection port 44 is shown passing through the production tree 42 and wellhead housing 43 and into the borehole 3. Each regulator 10 is in fluid communication with the fluid supply line 50 via lead lines 49 shown connected between the fluid supply line 50 and the opening 11 of each regulator 10.
In one mode of operation, an injection fluid is provided through line 46 where it flows through the injection port 44 and into the fluid supply line 50. After branching into the lead lines 49 the injection fluid is introduced to the regulator 10 via the opening 14 (
An additional advantage is the modular design of the flow regulator 10. The constant flow valve 24 used in the flow regulator 10 described herein is readily interchangeable with a constant flow valve 24 rated for a different operating capability. Additionally, a constant flow valve 24 having a certain operating capability can be installed after being manufactured, such as on site at an oil/gas well. One example of a different operating capability includes a fluid flow rate across the constant flow valve 24. The readily interchangeable design, or ready installation, provides flexibility to meet operating conditions that may not be known or available before the regulator 10 is manufactured or delivered for use. Multiple exit ports 18 provided on the body 12 provide another advantage since injection nozzles downhole can clog from scale buildup or other debris in wellbore fluid. The plurality of ports 18 provides redundant exit points on the regulator 10 thereby significantly reducing the chances of clogging.
The pressure regulators 10 are illustrated in
While the invention has been shown in only one 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. In an alternate embodiment, devices for preventing backflow, such as a check valve, can be included within the lines 46, 50, 49 that convey injection fluid.
The present application relates to U.S. provisional application 61/107,247 filed on Oct. 21, 2008, the entire specification of which being herein incorporated by reference.
Number | Date | Country | |
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61107247 | Oct 2008 | US |