Abstract:
A well completion has an inner completion with a control valve surrounded by spaced seals that is positioned in an outer completion, such as a sand control completion. A control line extends from the valve through one of the seals. 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:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    The following is also based upon and claims priority to U.S. provisional application serial No. 60/339,512, filed Oct. 26, 2001. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of Invention  
           [0003]    The present invention relates to the field of completions. More specifically, the invention relates to a device and method for a completing a well using an inner completion string.  
           [0004]    2. Related Art  
           [0005]    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 relatively recent development to increase production is the use of intelligent completions. Intelligent completions generally include downhole monitoring devices and control devices that are remotely actuatable from the surface. Intelligent completions as well as other types of completions require the use of control lines (e.g., electrical, fiber optic, and hydraulic lines and combinations thereof) that extend through the well to equipment positioned therein. Routing of the control lines is often an issue in a number of completions. For example, in sand control completions, the control line is typically run with the sand screens that are then gravel packed. When the production string is run and stabbed into the polished bore receptacle (PBR) of the sand screen completion, the control lines installed with the sand control completion must be connected to the surface. This connection is generally made with a wet connect which are generally considered undesirable.  
           [0006]    Additionally, once the sand control completion is gravel packed in the well, it is very difficult or impossible to remove. Accordingly, the equipment installed in the sand control completion generally cannot be replaced easily.  
           [0007]    In sand control completions having multiple zones, it is desirable to separate the production from and injection into the various zones.  
           [0008]    Also, there is a need for remedial completions inside preexisting completions or as a redundant option for new completions.  
         SUMMARY  
         [0009]    In general, according to one embodiment, the present invention provides a sand control completion in which an inner completion is run into a sand screen. The inner completion comprises the flow control equipment as well as the control line to the surface. In another embodiment, the present invention comprises an isolation seal assembly having a control line passageway therethrough.  
           [0010]    Other features and embodiments will become apparent from the following description, the drawings, and the claims. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    The manner in which these objectives and other desirable characteristics can be obtained is explained in the following description and attached drawings in which:  
         [0012]    [0012]FIG. 1 illustrates an embodiment of the present invention showing multiple zones.  
         [0013]    [0013]FIG. 2 illustrations a blown-up portion of FIG. 1 of the present invention.  
         [0014]    [0014]FIG. 3 illustrates an alternative embodiment of the present invention.  
         [0015]    [0015]FIG. 4 is an end view of an embodiment of a seal assembly of the present invention.  
         [0016]    [0016]FIG. 5 is a side, cross sectional view of an embodiment of a seal assembly of the present invention.  
         [0017]    [0017]FIG. 6 illustrates an alternative embodiment of the present invention.  
         [0018]    [0018]FIG. 7 illustrates an alternative embodiment in which a PBR is positioned between a screen and a circulating valve. 
     
    
       [0019]    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  
       [0020]    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.  
         [0021]    Although the figures show the invention used in a multi-zone completion, the present invention may be used in a single zone completion. Further, the present invention may be employed in some of the zones (e.g., one of the zones) of a multi-zone completion if desired.  
         [0022]    Referring to FIG. 1, a well  2  having a casing  4  therein extends through a plurality of perforated zones  6 . Each zone is completed with a sand screen completion  10 . The sand screen completion  10  may be as shown or use other sand screen completion methodologies and equipment. In the embodiment shown, the sand screen completion  10  comprises a sump packer  12  having a polished bore receptacle (PBR)  14  therein. Note that the PBR  30  may be incorporated into a separate piece of the completion. However, it is generally described herein as attached to or part of the packer for ease of discussion. The sump packer  12  is placed and set in the well below a zone  6 . A sand screen assembly  16 , comprising a sand screen  18  and a seal assembly  20  at its lower end, is attached to the lower end of a packer  22 . The sand screen assembly  16  is positioned in the well with the seal assembly  20  in sealing engagement with the PBR  14  of the sump packer  12 . The packer  22  of the sand screen assembly  16 , which also has a PBR  14  therein, is set, thereby isolating the associated zone  6  between the packers  12 ,  22 .  
         [0023]    If desired, a service string (not shown) is run into the well and the zone  6  is gravel packed by any desired method. U.S. Pat. No. 6,220,353, issued Apr. 24, 2001, discusses a gravel packing procedure and associated tools and is hereby incorporated by reference. Other methods of gravel packing the zone  6  are known and may be used with the present invention.  
         [0024]    If the well has multiple zones they may also be completed as described above. For example, the seal assembly  20  of a second sand screen assembly  16  stabs into the PBR  14  of the previously installed sand screen assembly  16 . Once the packer  22  of the second sand screen assembly  16  is set, the packers  22  of the two sand screen assemblies  16  isolate the additional, upper zone. The second zone may then be gravel packed. Additional zones may be completed in like manner.  
         [0025]    In an alternative embodiment, a multizone well sand screen completion  10  may be completed as described in U.S. patent application Ser. No. 09/631,859, filed Aug. 3, 2000 which is hereby incorporated herein by reference. In this embodiment, the gravel pack is accomplished through-tubing so that all of the hardware for the sand screen completion  10  for all zones may be installed before the gravel pack operation is performed. Similarly, a multizone well sand screen completion  10  may be completed as described in U.S. Pat. No. 6,311,772, issued Nov. 6, 2001 which is hereby incorporated herein by reference or may be completed in other known manners.  
         [0026]    Above and below each of the sand screens  18  is an inner PBR  30 . Note that, rather than providing inner PBRs  30  above and below each sand screen  18  in each sand screen assembly  16  of a multi-zone well  2 , each sand screen assembly  16  may have one inner PBR  30  below the sand screen  18 . However, the overall completion has at least one PBR  30  between the zones of the well. The inner PBR  30  of the two sand screen assemblies  16  providing isolation of the lowermost of the two sand screen assemblies  16 . The uppermost sand screen assembly  16  of the sand control completion  10  would then have an inner PBR  30  above its sand screen  18  to provide for isolation of that uppermost zone. However, the use of an upper and lower inner PBR  30  in each sand screen assembly  16  provides a redundant seal and a more reliable system. Generally, the sand screen assemblies  16  have a circulating valve  32  (FIG. 7) above the sand screen  18  that is used during gravel packing. The upper inner PBR  30  provides additional reliability in the case of a leak in the circulating valve. If a PBR  30  is placed between the circulating valve and the sand screen  18 , the circulating valve is isolated from the production by the PBR  30  once a completion  40  (discussed below) is put into place.  
         [0027]    A completion  40  run into the well  2  is inserted into the sand screen completion  10 . Seal assemblies  42  of the completion  40  mate with the inner PBRs  30  to isolate the associated zone(s). Flow entering the annulus formed between the sand screen  18  and the completion  40  is controlled with valves  44  in the completion  40 . The seal assemblies  42  and inner PBRs  30  provide for the control of flow through the valves  44 . Control lines  46  extend along the completion  40  through the seal assemblies  42  to provide power and telemetry to the valves  44  or other equipment in the well  2 .  
         [0028]    In the embodiment shown, the completion  40  comprises a production tubing  50  (or conduit) extending to the surface of the well  2 . A safety valve  52  and a packer  54  are positioned in the well  2  about the production tubing  50  above the sand control completion  10 . A seal assembly  42  attached to the production tubing  50  mates with the uppermost inner PBR  30 . Below the seal assembly  42 , is a control valve  44 . A seal assembly  42  below the control valve  44  mates with the inner PBR  30  below the sand screen  18  of the associated zone  6  to isolate the zone. Together, the seal assemblies  42  above and below a control valve  44  and the equipment therebetween are referred to collectively as an isolation assembly  56 . FIG. 2 illustrates one isolation assembly  56 . Although primarily described herein as isolating a single zone  6 , an isolation assembly  56  may bridge more than one zone  6  if desired.  
         [0029]    A control line  46  extends from the valve  44  and through the seal assembly  42  to a position above the sand control completion  10 . Generally, the control line  46  extends to the surface, but may extend to a downhole controller, power supply, or telemetry equipment, such as an inductive coupler or acoustic transmitter. Examples of control lines  46  are electrical, hydraulic, fiber optic and combinations of thereof. Other equipment may also be provided in the isolation assembly  56  or isolated portion that requires a control line  46  connected thereto. For example, the completion  40  may have intelligent completions devices such as gauges, sensors, valves, sampling devices, temperature sensors, pressure sensors, flow rate measurement devices, oil/water/gas ratio measurement devices, scale detectors, actuators, locks, release mechanisms, equipment sensors (e.g., vibration sensors), sand detection sensors, water detection sensors, data recorders, viscosity sensors, density sensors, bubble point sensors, composition sensors, resistivity array devices and sensors, acoustic devices and sensors, other telemetry devices, near infrared sensors, gamma ray detectors, H 2 S detectors, CO 2  detectors, downhole memory units, downhole controllers, locators, and other downhole devices therein. In addition, the control line  46  itself may comprise an intelligent completions device as in the example of a fiber optic line that provides functionality, such as temperature measurement, pressure measurement, and the like. In one example, the fiber optic line provides a distributed temperature functionality so that the temperature along the length of the fiber optic line may be determined. The control line  46  for such equipment would also extend through the seal assembly  42 .  
         [0030]    In a multi-zone well, such as that shown in FIG. 1, the completion  40  has additional isolation assemblies  56  corresponding to associated zones  6  as desired.  
         [0031]    In one embodiment, a locator device  60  ensures the proper alignment between the completion  40  and the sand control completion  10 . An example of a locator device is shown in FIG. 1. In that example, the bottom  62  of completion  40  lands on a shoulder  64  connected to a lower end of the sand control completion  10 . In that example, the shoulder  64  is positioned below the sump packer  12 . Numerous other types of locators may be used.  
         [0032]    [0032]FIGS. 4 and 5 provide a more detailed illustration of the seal assembly  42 . In many cases, the radial limitations of placing a completion  40  within the sand control completion  10  are stringent. To facilitate placement of the control lines  46  in the radially restricted space, the seal assembly  42  may be eccentric with the primary production passageway  66  offset from the centerline of the seal assembly  42 . An eccentric arrangement provides a relatively thicker side through which control line(s)  46  may extend. The control lines  46  extend through control line passageways provided in the body of the seal assembly  42 .  
         [0033]    In another embodiment, shown in FIG. 3, the completion  40  is used in conjunction with a preexisting completion  70  to provide a remedial system. As an example, a completion  70 , as described in U.S. patent application Ser. No. 09/732,134, filed Dec. 7, 2000 which is hereby incorporated by reference herein, is provided in a well  2 . In one embodiment, the completion  70  has a sand screen  18  with a gravel pack. A base pipe  72  of the sand screen  18  is unperforated and defines a flow annulus  74  between the sand screen  18  and the base pipe  72 . The annulus communicates with a flow control valve  44  that controls the flow from the annulus  74  into the production string  50 .  
         [0034]    In the present embodiment, the completion  70  further includes a pair of inner PBRs  30  isolating the inlet to the production tubing (i.e., the valve  44  port). For example, an inner PBR  30  may be placed below the valve  44  and above the sand screen  18 . In this way, if the valve  44  fails, it can be locked open and an inner completion  40  may be run inside completion  70 . As in the previously described embodiment, the seal assemblies  42  of the completion  40  may mate with the inner PBRs to isolate the incoming flow which may then be controlled by the valve  44  in the inner completion  40 . This system will work in other situations wherein there is a specific area of ingress into the production tubing and an interior completion  40  is desired to control the flow therethrough, such as in cases of remediation.  
         [0035]    Although the isolation is described herein as using PBRs and seal assemblies, other types of isolation devices, such as packers and cup packers, may be used. In one embodiment an inner completion  40  of the present invention may be used in a pre-existing completion that does not have a PBR. In this embodiment, the inner completion uses inner packers  80  to isolate between the various zones. In this way, an intelligent completion may be provided in an existing well. Referring to FIG. 6, one example of this embodiment is shown. In FIG. 6, the pre-existing completion comprises an upper packer  22 , a sand screen  18  in each of the zones, and a packer  22  isolating the two zones. The inner completion  40  comprises a valve  44  for each of the zones and inner packers  80  on isolating the valves  44  from one another. The inner packers  22  seal between the inner string  82  and the pre-existing completion. The inner packers  22  and valves  44  are positioned in the well so that flow of each of the screens or zones is isolated from the flow of other screens or zones (although one valve could be used for multiple zones if desired). A control line  46  may run from the surface or from a downhole controller to each of the valves  44  so that the position of the valve may be controlled. Other intelligent completions devices may be placed in the inner completion  40  as well. The control line  46  may extend through bypass lines in the inner packers  80  which may be eccentric to provide additional area for running of the control lines  46  therethrough.  
         [0036]    When a device is described herein as providing a seal, some leakage through the seal may occur. Thus, a seal includes an arrangement that substantially restricts the flow. The term “seal” as used herein refers generically to seal assemblies, packers, cup packers, and other isolation devices.  
         [0037]    Also note that in each of the above-described embodiments, the sand screen  18  may be replaced with a slotted liner as an alternative form of sand control. The term “sand control device” is used to generally describe sand screens, liners, and other types of conduits used to prevent migration of sand into the production.  
         [0038]    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.