Patent Publication Number: US-7708068-B2

Title: Gravel packing screen with inflow control device and bypass

Description:
BACKGROUND 
   The present invention relates generally to equipment utilized and operations performed in conjunction with a subterranean well and, in an embodiment described herein, more particularly provides a gravel packing screen with an inflow control device and a bypass. 
   Although some wells can be completed with sand control screens for controlling sand production, many wells are benefited by additionally having a gravel pack placed around the screens. Furthermore, some well completions are benefited by having flow restrictors, such as inflow control devices, integral to the screens to restrict the flow of produced fluid through the screens. In some cases, the inflow control devices may variably restrict the fluid flow, and may have the capability to respond to changed downhole conditions and/or be remotely controlled (e.g., “intelligent” inflow control devices). Very long horizontal open hole completions can benefit substantially from the use of inflow control devices in screens. 
   In spite of these facts, few (if any) wells have been completed with a screen having an integral inflow control device and with a gravel pack installed about the screen. This may be due to the fact that the presence of the inflow control device integral to the screen would impair or prevent the successful placement of the gravel pack around the screen when using conventional slurry pumping techniques, since the inflow control device significantly restricts the available flow rate through the screen during the gravel packing operation. Conventional slurry pumping techniques require a much greater flow rate through the screen at certain points in the gravel packing operation than is practically possible with the inflow control device in place. 
   Therefore, it may be seen that improvements are needed in the arts of well screen construction and gravel packing. It is among the objects of the present invention to provide such improvements. 
   SUMMARY 
   In carrying out the principles of the present invention, a new well screen and associated methods are provided which solve at least one problem in the art. One example is described below in which a screen includes an inflow control device and a bypass to divert flow around the inflow control device. Another example is described below in which a gravel packing operation is conducted while the bypass is open, and then the bypass is closed so that flow is no longer diverted around the inflow control device during production. 
   In one aspect of the invention, a well screen includes a flow restricting device for restricting inward flow through the screen. A bypass device is used to vary a proportion of the inward flow which passes through the flow restricting device. The bypass device includes a material which swells in response to contact between the material and fluid in a well. 
   In another aspect of the invention, a method of gravel packing a well includes the steps of: installing a well screen in the well, the screen including a flow restricting device which restricts flow through the screen, and a bypass device for selectively permitting relatively unrestricted flow through the screen; and actuating the bypass device in response to contact between a material in the bypass device and fluid in the well, thereby increasingly restricting flow through the screen. 
   In yet another aspect of the invention, a well system is provided. The well system includes a well screen with a flow restricting device for restricting inward flow through the screen, and a bypass device for increasing a proportion of the inward flow which passes through the flow restricting device. The bypass device includes a material which swells in response to contact between the material and fluid in the well. 
   In a further aspect of the invention, a method of gravel packing a well includes the step of: installing a well screen in the well, the screen including a flow restricting device which restricts flow through the screen, and a bypass device for selectively permitting relatively unrestricted flow through the screen. Flow through the flow restricting device and flow through the bypass device are in parallel. The method further includes the step of actuating the bypass device, thereby increasingly restricting flow through the screen. 
   These and other features, advantages, benefits and objects of the present invention will become apparent to one of ordinary skill in the art upon careful consideration of the detailed description of representative embodiments of the invention hereinbelow and the accompanying drawings, in which similar elements are indicated in the various figures using the same reference numbers. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic partially cross-sectional view of a well system embodying principles of the present invention; 
       FIG. 2  is an enlarged scale schematic cross-sectional view through a well screen in the system of  FIG. 1 ; 
       FIG. 3  is a schematic cross-sectional view of the well screen of  FIG. 2 , with a bypass device of the screen being closed; 
       FIG. 4  is a schematic cross-sectional view of a first alternate construction of the well screen; 
       FIG. 5  is a schematic cross-sectional view of the well screen of  FIG. 4 , with a bypass device of the screen being closed; 
       FIG. 6  is a schematic cross-sectional view of a second alternate construction of the well screen, a bypass device of the screen being shown closed on a left-hand side of the figure, and the bypass device of the screen being shown open on a right-hand side of the figure; 
       FIG. 7  is a schematic cross-sectional view of a third alternate construction of the well screen, a bypass device of the screen being shown closed on a left-hand side of the figure, and the bypass device of the screen being shown open on a right-hand side of the figure; 
       FIG. 8  is a schematic cross-sectional view of a fourth alternate construction of the well screen, a bypass device of the screen being shown closed on a left-hand side of the figure, and the bypass device of the screen being shown open on a right-hand side of the figure; and 
       FIG. 9  is an enlarged scale schematic cross-sectional view of a swellable material of a bypass device sealingly contacting a surface of the bypass device. 
   

   DETAILED DESCRIPTION 
   It is to be understood that the various embodiments of the present invention described herein may be utilized in various orientations, such as inclined, inverted, horizontal, vertical, etc., and in various configurations, without departing from the principles of the present invention. The embodiments are described merely as examples of useful applications of the principles of the invention, which is not limited to any specific details of these embodiments. 
   In the following description of the representative embodiments of the invention, directional terms, such as “above”, “below”, “upper”, “lower”, etc., are used for convenience in referring to the accompanying drawings. In general, “above”, “upper”, “upward” and similar terms refer to a direction toward the earth&#39;s surface along a wellbore, and “below”, “lower”, “downward” and similar terms refer to a direction away from the earth&#39;s surface along the wellbore. 
   Representatively illustrated in  FIG. 1  is a well system  10  which embodies principles of the present invention. A gravel packing method is being performed in the well system  10  as depicted in  FIG. 1 , with a gravel slurry  12  being flowed into an annulus  18  between a completion string  20  and a wellbore  22 . In this manner, a gravel pack  16  is installed about a well screen  14  interconnected in the completion string  20 . 
   In one important feature of the well system  10 , the well screen  14  is provided with a flow restricting device for restricting inward flow through the screen during production, and is also provided with a bypass device which permits relatively unrestricted inward flow through the screen until after the gravel packing operation. This feature allows greater flow rates through the screen  14  before and during the gravel packing operation, but also obtains the benefits of reduced flow rates through the screen during production. 
   Although the wellbore  22  is depicted in  FIG. 1  as being cased, it should be understood that the wellbore could be completed open hole in keeping with the principles of the invention. In addition, although the screen  14  is shown as being positioned in a generally vertical portion of the wellbore  22 , such screens may alternatively, or in addition, be positioned in horizontal or otherwise deviated portions of a wellbore. 
   Referring additionally now to  FIG. 2 , an enlarged scale cross-sectional view of the screen  14  is representatively illustrated. This view depicts the screen  14  during the gravel packing operation. 
   A fluid portion  24  of the gravel slurry  12  flows inwardly through a filter portion  26  of the screen  14 . The filter portion  26  is depicted in  FIG. 2  as being made up of wire wraps, but other types of filter material (such as mesh, sintered material, etc.) may be used in other embodiments. 
   The fluid portion  24  enters an annular space  28  between the filter portion  26  and a tubular base pipe  30  of the screen  14 . A portion  32  of the fluid then passes through a flow restricting device  34 , and another portion  36  of the fluid passes through a bypass device  38 . 
   The bypass device  38  permits relatively unrestricted inward flow through the screen  14  prior to and during the gravel packing operation. However, the bypass device  38  can be actuated to increase the proportion of fluid which passes through the flow restricting device  34 , thereby increasing the restriction to flow through the screen, as described more fully below. 
   The flow restricting device  34  may be of the type known to those skilled in the art as an inflow control device. As depicted in  FIG. 2 , the device  34  utilizes relatively small diameter tubes  40  (only one of which is visible in  FIG. 2 ) to restrict inward flow through the screen  14  (i.e., between the annulus  18  and an inner passage  42  formed through the screen). 
   However, it should be clearly understood that any type of flow restricting device may be used for the device  34  in keeping with the principles of the invention. For example, some inflow control devices use tortuous passages, orifices and/or other flow restricting elements to restrict inward flow through a screen. 
   In addition, the flow restricting device  34  may be “intelligent” in that the device may be remotely controlled and/or the device may be capable of responding to changed downhole conditions in order to variably restrict inward flow through the screen  14 . For this purpose, the device  34  may include a downhole controller  44  which may include a telemetry device for communicating with the surface or another remote location. 
   Preferably, the flow restricting device  34  is an integral part of the screen  14 , so that the flow restricting device is installed when the screen is installed in the well system  10 . In this manner, an intervention into the well is not required to install the flow restricting device  34 . However, other configurations are possible in keeping with the principles of the invention. 
   The bypass device  38  includes a material  46  which swells (increases in volume) when contacted with a certain fluid in the well. For example, the material  46  could swell in response to contact with water, in response to contact with hydrocarbon fluid, or in response to contact with gas in the well, etc. Ports  50  may be provided in the bypass device  38  to increase a surface area of the material  46  exposed to the fluid in the well. 
   Examples of swellable materials are described in U.S. patent application publication nos. 2004-0020662, 2005-0110217, 2004-0112609, and 2004-0060706, the entire disclosures of which are incorporated herein by this reference. Other examples of swellable materials are described in PCT patent application publication nos. WO 2004/057715 and WO 2005/116394, the entire disclosures of which are incorporated herein by this reference. 
   The bypass device  38  also includes ports or passages  48  through which the fluid portion  36  flows prior to and during the gravel packing operation. Note that in  FIG. 2  the material  46  permits relatively unrestricted flow of the fluid portion  36  through the passages  48 . 
   Preferably, the bypass device  38  is an integral part of the screen  14 , so that the bypass device is installed when the screen is installed in the well system  10 . In this manner, an intervention into the well is not required to install the bypass device  38 . However, other configurations are possible in keeping with the principles of the invention. 
   Referring additionally now to  FIG. 3 , the screen  14  is representatively illustrated after the material  46  has swollen in response to contact with a fluid in the well. Flow through the passages  48  is now prevented, and all of the inward flow through the screen  14  must pass through the flow restricting device  34 . In this manner, inward flow through the screen  14  is increasingly restricted due to swelling of the material  46 . 
   The swollen material  46  itself blocks flow through the passages  48 . However, note that it is not necessary for the material  46  to completely prevent flow through the passages  48 , since it may be sufficient in some circumstances for the material to just increasingly restrict flow through the passages. 
   After the gravel packing operation, all (or at least an increased proportion) of the inward flow passes through the flow restricting device  34 , rather than through the bypass device  38 . Thus, the fluid portion  32  will consist of fluid  52  produced through the filter portion  26 . 
   Swelling of the material  46  could be initiated during or after the gravel packing operation by, for example, circulating a certain fluid down to the screen  14  with, or after, the slurry  12 . Alternatively, the produced fluid  52  could contact the material  46  and cause it to swell after the gravel packing operation. 
   As another alternative, the swelling of the material  46  could be initiated by the same fluid as is in the well at the time that the screen  14  and its bypass device  38  are installed in the well. In that case, the swelling of the material  46  could be retarded, so that the closure or increased restriction through the bypass device  38  would not be completed until a desired subsequent time, such as after the gravel packing operation is at least substantially complete. The swelling of the material  46  could be retarded by, for example, designing the material composition so that it swells slowly, covering the material with another material which is only slowly penetrable by the well fluid or swells at a relatively slow rate, providing a cover or coating on the material to limit contact between the material and the well fluid, etc. 
   Any manner of contacting the material  46  with the fluid which causes the material to swell may be used at any time, and initiation of the contact between the material and the well fluid to cause the material to swell may occur at any time, in keeping with the principles of the invention. 
   Referring additionally now to  FIG. 4 , an alternate configuration of the screen  14  is representatively illustrated. In this configuration, the bypass device  38  further includes a closure member  54  which is displaced by the material  46 . 
   The member  54  is in the form of a sleeve which carries spaced apart internal seals. Other types of closure or choking members may be used without departing from the principles of the invention. 
   As depicted in  FIG. 4 , relatively unrestricted flow is permitted through the passages  48 . Thus, a greater proportion of fluid flows through the bypass device  38 , instead of through the flow restricting device  34 . 
   Referring additionally now to  FIG. 5 , the alternate configuration of the screen  14  is representatively illustrated after the material  46  has been swollen. Swelling of the material  46  has caused the member  54  to displace to a position in which the member blocks the passages  48 , preventing flow through the passages. 
   It is not necessary for the member  54  to completely prevent flow through the passages  48 , since in some circumstances it may be acceptable for flow through the passages to be increasingly restricted. Preferably, at least a greater proportion of fluid is forced to flow through the flow restricting device  34 , rather than through the bypass device  38 , due to the displacement of the member  54 . 
   In the constructions of the screen  14  as depicted in  FIGS. 2-5 , the bypass device  38  operates as a valve or choke to variably restrict flow through the passages  48 . In the constructions of  FIGS. 4 &amp; 5 , the material  46  is an actuator for the valve, since the material supplies the force required to block flow through the passages  48 . The material  46  is also a closure member in the construction of the screen  14  as depicted in  FIGS. 2 &amp; 3 . 
   Referring additionally now to  FIG. 6 , another alternate configuration of the well screen  14  is representatively illustrated. In this configuration, the flow restricting device  34  and bypass device  38  are both incorporated into an upper end of the screen  14 . On a right-hand side of the screen  14  as viewed in  FIG. 6  the bypass device  38  is open, and on a left-hand side of the screen the material  46  has swollen to close the bypass device. 
   The flow restricting device  34  and bypass device  38  are depicted in  FIGS. 2-5  as being separate elements of the screen  14 . However, the configuration of  FIG. 6  demonstrates that these elements may be combined into a single structure, and that a variety of alternate constructions may be used in the screen  14  in keeping with the principles of the invention. 
   Prior to and during a gravel packing operation, relatively unrestricted flow is permitted through an annular passage  58  of the bypass device  38  as depicted on the right-hand side of  FIG. 6 . The annular passage is formed between the material  46  and the tube  40 . The fluid portion  36  flows through this passage  58 . 
   More restricted flow is also permitted through a relatively small diameter passage (not visible in  FIG. 6 ) formed in the tubes  40 . The fluid portion  32  flows through the tubes  40 . 
   When the material  46  swells, it blocks (or at least increasingly restricts) flow through the passage  58 , so that a greater proportion of fluid is forced to flow through the tubes  40 . In this manner, the restriction to fluid flow through the bypass device  38  may be increased during or after the gravel packing operation. 
   Referring additionally now to  FIG. 7 , another alternate configuration of the screen  14  is representatively illustrated. On a right-hand side of the screen  14  as viewed in  FIG. 7 , the bypass device  38  is open, and on a left-hand side of the screen the material  46  has swollen to thereby close the bypass device. 
   In this embodiment the swellable material  46  is bonded to an inner surface  72  of an outer tubular component of the bypass device  38 , thereby forming an annular space  74  between an inner surface of the swellable material and an outer surface  76  of an inner tubular component of the bypass device. Prior to and during a gravel packing operation, relatively unrestricted flow is permitted through this annular space  74  of the bypass device  38 . When the swellable material  46  swells radially inward in response to contact with a certain well fluid, the annular space  74  is closed or at least reduced in size so as to stop or at least increasingly restrict flow through the annular space. 
   Another alternative embodiment of the device shown in  FIG. 8  has the swellable material  46  bonded to the outer surface  76  of the inner tubular component of the bypass device  38 , with the annular space  74  formed between the outer surface of the swellable material and the inner surface  72  of the outer tubular component of the bypass device. On a right-hand side of the screen  14  as viewed in  FIG. 8 , the bypass device  38  is open, and on a left-hand side of the screen the material  46  has swollen to thereby close the bypass device. The swellable material  46  would swell radially outward upon contact with a certain well fluid in order to close, or at least increasingly restrict, flow through the annular space  74 . 
   In any of the embodiments of the bypass device  38  as shown in  FIGS. 6-8 , the surface with which the swellable material  46  makes contact may be enhanced so as to aid in the swellable material effecting a seal against that receiving surface. The surface may be roughened or it may be undulating, corrugated, or otherwise made non-smooth so as to enhance the sealing capability of the swellable material  46  when it contacts the receiving surface. 
   An example of such surface treatments is shown in  FIG. 9 . The inner surface  72  of the bypass device  38  is contacted by the material  46 , as in the embodiment of  FIG. 8 . In the example shown in  FIG. 9 , the inner surface  72  has serrations or ridges formed thereon to enhance sealing contact between the material  46  and the surface. 
   It should be understand that, although the screen  14  has been described above as being used in a gravel packing operation and in the well system  10  in which the screen is gravel packed, it is not necessary for the screen to be used in such gravel packing operations or well systems. For example, the screen  14  (or any screen incorporating principles of the invention) could be used in well systems where the screen is not gravel packed, or in operations where a restriction to flow through the screen is not increased in relation to any gravel packing operation. 
   It may now be fully appreciated that the well screen  14  and its many embodiments described above provide significant improvements in the art. Note that, in each of the embodiments of  FIGS. 2-8 , the fluid portion  36  which flows through the bypass device  38  flows in parallel with the fluid portion  32  which flows through the flow restricting device  34 . In this manner, the closing or increased restriction to flow through the bypass device  38  which results from swelling of the material  46  causes an increased proportion of the fluid  52  to flow through the flow restricting device  34 . Another manner of describing this feature is that the fluid portion  36  which flows through the bypass device  38  does not necessarily flow through the flow restricting device  34 , and the fluid portion  32  which flows through the flow restricting device does not necessarily flow through the bypass device. 
   One advantage to using a well screen incorporating principles of the invention would be to enable higher flow rates, either production or injection, during an initial phase of installation, following which phase the actuation of the bypass device will function to restrict all or most flow from or into the well to no more than that allowed through the flow restricting device. Such an initial phase of higher production or injection rate may benefit the well by enabling it to maintain a higher sustained production or injection over the life of the well. 
   Well screens incorporating principles of the invention may be used in injection or production operations without gravel packing. Screens incorporating principles of the invention may be used to permit a large initial flow rate, for example, to aid in breaking up a filter cake lining the wellbore, or to permit high flow rate acidizing or other stimulation treatments, prior to long term production or injection. 
   Of course, a person skilled in the art would, upon a careful consideration of the above description of representative embodiments of the invention, readily appreciate that many modifications, additions, substitutions, deletions, and other changes may be made to these specific embodiments, and such changes are within the scope of the principles of the present invention. For example, it will be appreciated that bypass devices may be constructed without the use of swellable material, since other types of valves or chokes may be used which do not utilize swellable material. Accordingly, the foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the present invention being limited solely by the appended claims and their equivalents.