Patent Publication Number: US-9896905-B2

Title: Inflow control system for use in a wellbore

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present disclosure relates in general to a system for draining a wellbore with an inflow control system that has a diameter that increases substantially continuously with distance away from a lower end of the wellbore. 
     2. Description of Prior Art 
     Wellbores for the production of hydrocarbon are typically lined with casing, which is then perforated adjacent a producing or formation zone. Fluid produced from the zone is typically directed to surface within production tubing that is inserted within the casing. Formation fluids generally contain stratified layers of gas, liquid hydrocarbon, and water. Boundaries between these three layers are often not highly coherent, thereby introducing difficulty for producing a designated one of the fluids. Also, the formation may have irregular properties or defaults that cause production to vary along the length of the casing. It is usually desired that the fluid flow rate remain generally consistent along the length of the casing. 
     A fluid flow rate from one formation that varies within the casing may inadvertently cause production from another of the formation zones. This is especially undesirable when water is present in the other formation zone, which can lead to a water breakthrough into the primary flow. To overcome this problem and to control frictional losses in wells, an inflow control device (“ICD”) is sometimes provided in the wellbore. The ICD is useful for controlling fluid flow into the wellbore and for controlling pressure drop along the wellbore. Multiple fluid flow devices may be installed, each controlling fluid flows along a section of the wellbore. These fluid control devices may be separated from each other by conventional packers. Other benefits of using fluid control devices include increasing recoverable reserves, minimizing risks of bypassing reserves, and increasing completion longevity. 
     SUMMARY OF THE INVENTION 
     Disclosed herein is an example of a well system for use in a wellbore, and which includes an elongated tapered body, an inlet on an end of the body proximate to a lower end of the wellbore, an outlet on an end of the body distal from the inlet, openings formed radially through a sidewall of the tapered body, and an inner diameter of the body that widens a uniform amount per linear distance from the inlet to the outlet. The body can have a series of annular inflow control devices joined in series, wherein each of the inflow control devices can be an annular member having an inlet, an outlet with a diameter greater than a diameter of the inlet, and wherein an inner diameter of each inflow control device increases linearly between their respect inlets and outlets. In one example, when fluid flows through the tapered body, the enlarging of the inner diameter provides a constant pressure drop of the fluid flow per unit length. The openings can be substantially elongated, or may have an outer periphery that is substantially curved. Packers may optionally be disposed between the body and an inner surface of the wellbore. In one embodiment, the body is disposed in a substantially horizontal portion of the wellbore. Alternatively, the body is adjacent more than one fluid producing zone intersected by the wellbore. 
     Also disclosed is a well system for use in a wellbore and which is made up of an elongate tapered member disposed in a horizontal portion of the wellbore and having an inner diameter that increases linearly with distance away from a bottom end of the wellbore, an inlet on an end of the tapered member that is proximate the bottom end of the wellbore, and an outlet on an end of the tapered member distal from the inlet and that has a diameter greater than a diameter of the inlet. In one example, the tapered member is made of annular inflow control devices joined together in series. An outlet of each inflow control device can insert into an inlet of an adjacent downstream inflow control device to define a junction, wherein the junction has a diameter than uniformly changes with axial unit distance within the tapered member. The well system can further include openings formed radially, or tangentially, through a sidewall of the tapered member. 
     Another example of a well system for use in a wellbore includes a series of tapered. inflow control devices joined in series to form an elongated tapered member, an inlet end on the tapered member proximate a bottom of the wellbore, an exit end on the tapered member distal from the inlet end, joints defined where each of the inflow control devices are joined, and an inner diameter of the tapered member that increases linearly from the inlet end to the exit end and along each of the joints, so that when fluid flows through the tapered member, a constant pressure drop is attained in the fluid flow. The well system can further include packers that circumscribe the tapered member and extend radially outward into sealing contact with the wellbore. Openings may optionally be provided in a sidewall of the inflow control devices that provide a fluid flow path from the wellbore and into the tapered member. In one example, the tapered member is in a horizontal portion of the wellbore. In an alternate embodiment, the tapered member is adjacent more than one subterranean zone that produces wellbore fluid. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Some of the features and benefits of the present invention having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a partial sectional view of an example of an inflow control device disposed within a wellbore. 
         FIG. 2  is a partial sectional view of a string of inflow control devices within a wellbore that define an inflow control system. 
     
    
    
     While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF INVENTION 
     The method and system of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments 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 thorough and complete, and will fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout. In an embodiment, usage of the term “about” includes +/− 5% of the cited magnitude. In an embodiment, usage of the term “substantially” includes +/− 5% of the cited magnitude. 
     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 
       FIG. 1  shows in a side sectional view an example of a wellbore  10  formed through a subterranean formation  12 . The wellbore  10  includes a vertical portion  14  and a bend  16  where the vertical portion  14  transitions into a horizontal portion  18 . Shown disposed adjacent a lower end  19  of the wellbore  10  is an example of an inflow control device (“ICD”)  20  for controlling fluid flow within the wellbore  10 . The ICD  20  is made up of an annular body  22  with an internal diameter ID that increases (or tapers) from its inlet  24  to its exit  26 . More specifically, in the illustrated example the internal diameter ID increases linearly so that the increase of the internal diameter ID is constant along the axial length of the ICD  20 . Also illustrated in  FIG. 1  is that the diameter D I  at the inlet  24  is less than the diameter D O  at the exit  26 . Optionally, packers  28  can be included in the wellbore  10  and that circumscribe the ICD  20  at spaced apart axial locations from one another. Openings  30  are schematically depicted formed radially through a sidewall of the ICD  20  and for allowing flow from the formation  12  to enter into the ICD  20  and be directed to surface. Alternatively, openings  30  can be formed tangentially through sidewall of the ICD  20 . 
       FIG. 2  shows multiple ICDs  201 ,  202 ,  203  joined together in series. Joints  321 ,  322  are formed respectively where ICDs  201 ,  202  are joined and where ICDs  202 ,  203 , are joined. The ICDs  201 ,  202 ,  203  joined together as shown define an inflow control system  34 . The respective outer diameters of the outlets  261 ,  262  are strategically sized to match inner diameters of the inlets  242 ,  243  so that the inner diameter ID of the inflow control system  34 , like the individual ICDs  201 ,  202 ,  203  increases linearly along the axial length of the inflow control system  34 . An advantage of maintaining the ID of the inflow control system  34  to be linearly increasing is that when fluid is flowing through the inflow control system  34 , a pressure drop of the fluid can remain substantially constant per unit length. As described above, maintaining a constant per unit pressure drop can maintain a pressure of the flowing fluid above a threshold value and thereby prevent inflow of fluid from other formations. Maintaining fluid pressure can also avoid or delay water breakthrough into the flow of fluid in the inflow control system  34 . 
     Further shown in  FIG. 2  is that the formation  12  includes a boundary  36  that intersects the horizontal portion  18  of the wellbore  10 . The boundary  36  defines a border between adjacent zones  38 ,  40 . In one example, conditions in zone  38  are different from conditions in zone  40 . For example, zone  38  can have a different pressure than zone  40 , or can contain/produce a different fluid than zone  40 . Implementation of the inflow control system  34  can maintain a sufficient pressure when producing fluid from zone  38 , such that fluid from zone  40  is prevented from penetrating through the openings  30  formed in the sidewall of the inflow control system  34 . As such, should water be present in zone  40 , the water can be kept out of the fluid being produced from zone  38  in the inflow control system  34 . 
     The present invention described herein, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While a presently preferred embodiment of the invention has been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. For example, the openings  30  can be slits, elongated slots, have a curved outer periphery, or be combinations thereof. These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the present invention disclosed herein and the scope of the appended claims.