Abstract:
A valve has a pair of surfaces, such as those of pipes, with an inflatable bladder disposed therebetween. Controlled inflation and deflation of the bladder provides for control of flow through the valve. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates to the field of flow control. More specifically, the invention relates to a device and method for controlling flow using an inflatable element. 
     2. Related Art 
     Oil companies are continually improving their recovery systems to produce oil and gas more efficiently and economically from sources that are continually more difficult to exploit, without significantly increasing the cost to the consumer. One area in which the industry has strived for improvement is in the area of flow control. Other industries have significant needs for improved flow control as well. 
     SUMMARY 
     In general, according to one embodiment, the present invention provides an inflatable flow control device. Other features and embodiments will become apparent from the following description, the drawings, and the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The manner in which these objectives and other desirable characteristics can be obtained is explained in the following description and attached drawings in which: 
     FIG. 1 illustrates a well having two devices of the present invention therein. 
     FIGS. 2 and 3 illustrate a side and end view of an embodiment of the present invention. 
     FIG. 4 illustrates another embodiment of the present invention. 
    
    
     It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following description, numerous details are set forth to provide an understanding of the present invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible. 
     FIG. 1 shows a well  10  with a casing  12  and a production tubing  14  therein. The well also contains two valves  20  of the present invention that control flow within the well  10 . A control line  30  extends from the surface to the valves  20 . The control line  30  communicates with the valves  20  allowing remote control of the valves  20 . 
     FIG. 2 discloses one embodiment of the present invention in the form of a fluid pressure actuated bladder valve. The bladder  44  of the invention is positionable in a section of pipe such that an outer diameter thereof is attached to the inner diameter of the pipe  40  and the inner orifice of the bladder  44  is open or closed depending upon the amount of pressure inside the bladder relative to ambient pressure in the vicinity of the bladder. A toroidal shaped bladder  44  is positioned in the inside of a pipe  40 . The bladder  44  may be bonded to the inside of the pipe  40  (the inside surface) using an adhesive or any other suitable attachment arrangement which includes but is not limited to a mechanical attachment magnetic element inside the bladder  44  which then pinches the wall of the bladder  44  between the magnetic element and the pipe  40  in which the bladder is positioned. Alternatively, the bladder  44  may be simply positioned in the pipe  40  and maintained in the desired position by friction caused by pressure internal to the bladder  44 . The bladder  44  may also be attached by other mechanical methods. The bladder  44  has an orifice  42  that allows fluid flow through pipe  40  when the bladder  44  is not inflated. The bladder  44  is preferably made of an elastic material that can be inflated and deflated repeatedly without structural degradation. Pressurization and depressurization of the bladder of the invention  44  is effected through a control line  45  that communicates with the interior of bladder  44 . The control line  45  is in sealed communication with bladder  44 . The control line  45  controls the pressure within the bladder  44  and can inflate or deflate the bladder  44  through hydraulic, pneumatic or other pressure sources. 
     Positioned within the pipe  40  and the bladder  44  is an inner pipe  46 . The inner pipe  46  may be attached to the pipe  40  at one or both ends. Any attachment mechanism may be used. The inner pipe  46  in one embodiment has a plug  48  that prevents flow through the inner pipe  46 . Although shown as a permanently attached plug in FIG. 2, the plug  48  may be a removeable plug, a flapper valve, or some other type of valve or plug that prevents flow through the inner pipe. Using a flapper valve or removeable plug facilitates access through the inner pipe  46  if needed, such as for re-entry, as well as opening of a flowpath through the valve  20  should the valve  20  fail. 
     In an alternative embodiment, the inner pipe  46  does not have a plug  48  therein. Instead, the inner pipe extends to a packer or other sealing device that prevents flow between the interior of the inner pipe  46  and the annulus between the inner pipe  46  and the outer pipe  40  in the area or zone of interest. 
     When inflated, the bladder  44  expands. Because expansion radially outwardly is inhibited by the pipe  40  in which the bladder  44  is located, the expansion is limited to radially inward and longitudinal. As the bladder undergoes radial inward expansion, the flow area between the pipe  40  and the inner pipe  46  decreases, restricting the flow therethrough. When fully inflated, the bladder  44  tends to close off orifice  42  (the annular flowpath between the pipe  40  and the inner pipe  46 ) by sealing against the outer surface of the inner pipe  46 , thus sealing flow through the pipe  40 . Desired flow through the pipe  40  can be achieved through applying a determined amount of fluid pressure to the bladder  44  to vary the flow area between opened and closed and provide for a variable orifice valve. Accordingly, the inflatable bladder  44 , controls the flow between a first surface and a second surface of a tool or tools. Although described as creating a seal when closed, it should be noted that some flow through the valve  20  (e.g. five percent of full fully open flow) may be permissible and the term “closed” includes substantially closed in which there is some flow through the valve  20 . 
     FIG. 3 is an end view of the pipe  40  shown in FIG. 2 including the pressure controlled valve  20  positioned inside of the pipe  40 . As noted above, the centrally located orifice  42  may be opened or closed by deflating or inflating the bladder  44  to control flow through the pipe  40 . 
     Due to the simplicity of design, the pressure controlled valve can withstand numerous cycles of opening and closing without failure. This reliability makes the pressure controlled valve ideal for applications such as downhole flow control and other applications, where ambient conditions are adverse and valve maintenance or replacement is difficult. 
     The pressure controlled valve may be controlled from the surface of the well or through downhole intelligence located within the well. A representative downhole intelligent control is schematically illustrated in FIG. 2 but it will be appreciated that the invention is also capable without the intelligent systems illustrated. Downhole intelligence, intelligent sensor arrangements, (e.g., position sensors, pressure sensors, temperature sensors, etc.) and communications for communicating to a downhole or surface microprocessor via any conventional communication device or media such as telemetry devices, wireline, TEC wire, cable, etc., are beneficial to the operation of the above-described valve. By monitoring conditions downhole, metered adjustments of the pressure controlled valve can be made to boost efficiency and production of any given well. This type of downhole intelligence is employable and desirable in connection with all of the embodiments disclosed herein and while only some of the embodiments contain direct reference to intelligent systems and controls it will be understood that these can be for all of the embodiments. 
     FIG. 4 shows an alternative embodiment of the present invention. In the figure, the well  10  contains two valves  20 , each controlling flow from a separate formation,  50  and  52 . A packer  60  seals between an inner pipe  44   46  and a casing  12  in the well  10 . The bladder  44  (or elements) for the valve  20  are connected to the inner pipe  46 . An outer pipe  40  extends from the packer to a position radially surrounding the bladder  44 . Ports  62  through the inner pipe  46  are positioned between the packer  60  and the bladder  44 . Thus, the valve  20  defines a flowpath from the free end of the outer pipe  40  through the annulus between the outer pipe  40  and the inner pipe  46 , past the bladder  44 , through the ports  62 , and into the inner pipe  46  for continued, controlled flow through the packer  60 . Flow through the control line  45  controls inflation and deflation of the bladder and, thus, the variable flow through the valve  20 . It should be noted that, although the figure shows two valves  20  sharing a common inner pipe  46 , each of the valves  20  may have a separate inner pipe  46 . Also, the figure discloses a separate control line for each valve  20 , multiple valves may share one control line. In one example, multiple redundant valves may be used to control the flow from one formation (or multiple formations) and may share a common control line. 
     The above-described system refers to a control line provided from the surface. However, other actuating systems may be used. For example, the electro-hydraulic actuator of U.S. Pat. No. 6,012,518, which is hereby incorporated herein by reference, may be used to inflate and deflate the bladder  44  of the present invention. Other downhole actuators may be used. 
     Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. §112, paragraph 6 for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function.