Patent Publication Number: US-11384628-B2

Title: Open hole displacement with sacrificial screen

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based on and claims priority to U.S. Provisional Application Ser. No. 62/686,501, filed Jun. 18, 2018, which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     In various well applications, a wellbore is drilled into a hydrocarbon bearing reservoir and an open hole completion is deployed. With open hole completions, the drilling fluid is displaced by completions fluid which is delivered downhole. There are several methodologies that can facilitate this process. Some of those methodologies are employed prior to setting the gravel pack packer while others are employed after setting the gravel pack packer. 
     With respect to methodologies occurring following setting of the packer, various approaches may be employed. For example, when a standard sand screen is used in a standard circulation, the fluid is moved through the screen wellbore/casing annulus until such point that it is energetically more favorable for the carrier fluid to pass through the screen jacket, base pipe perforations, and wash pipe/base pipe annulus before entering the wash pipe to return to the casing annulus and then to the surface. This is reversed for the reverse circulation. When using sand screens which incorporate inflow control devices, however, flow through the sand screens is greatly restricted. This leads to a situation where fluid distributes itself (in inflow or outflow) across the entire completion. Such distribution leads to an inefficient sweep of the open hole which can result in poor results from subsequent gravel packing operations. 
     SUMMARY 
     In general, a downhole completion system and methodology is provided for use in a well. The downhole completion comprises a packer and a plurality of flow control sand screens. Each flow control sand screen has an inflow control device (ICD). The downhole completion further comprises at least one lower sand screen positioned below the plurality of flow control sand screens. The at least one lower sand screen is configured without an ICD and may be used as a sacrificial screen. A flow restrictor is disposed between the plurality of flow control sand screens and the at least one lower sand screen. 
     However, many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Certain embodiments of the disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood, however, that the accompanying figures illustrate the various implementations described herein and are not meant to limit the scope of various technologies described herein, and: 
         FIG. 1  is a partially cutaway illustration of an example of a completion system which may be deployed in an open hole borehole, according to an embodiment of the disclosure; 
         FIG. 2  is a schematic illustration of an example of a downhole completion constructed to facilitate a fluid displacement process and deployed in an open borehole, according to an embodiment of the disclosure; 
         FIG. 3  is a schematic illustration similar to that of  FIG. 2  but during a different operational stage, according to an embodiment of the disclosure; 
         FIG. 4  is a schematic illustration similar to that of  FIG. 3  but during a different operational stage, according to an embodiment of the disclosure; 
         FIG. 5  is a schematic illustration similar to that of  FIG. 4  but during a different operational stage, according to an embodiment of the disclosure; 
         FIG. 6  is a schematic illustration similar to that of  FIG. 5  but during a different operational stage, according to an embodiment of the disclosure; 
         FIG. 7  is a schematic illustration similar to that of  FIG. 6  but during a different operational stage, according to an embodiment of the disclosure; 
         FIG. 8  is a schematic illustration similar to that of  FIG. 7  but during a different operational stage, according to an embodiment of the disclosure; 
         FIG. 9  is a schematic illustration similar to that of  FIG. 8  but during a different operational stage, according to an embodiment of the disclosure; 
         FIG. 10  is a cross-sectional illustration of an example of a flow restrictor which may be positioned between sand screens with and without an inflow control device (ICD), according to an embodiment of the disclosure; 
         FIG. 11  is a schematic illustration similar to that of  FIG. 10  but during a different operational stage, according to an embodiment of the disclosure; and 
         FIG. 12  is a schematic illustration similar to that of  FIG. 10  but during a different operational stage, according to an embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, numerous details are set forth to provide an understanding of some embodiments of the present disclosure. However, it will be understood by those of ordinary skill in the art that the system and/or methodology may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible. 
     The present disclosure generally relates to a system and methodology which facilitate a fluid displacement process in which drilling fluid is displaced by completions fluid. According to an embodiment, a downhole completion system is provided for use in a well. The downhole completion comprises a packer and a plurality of flow control sand screens. Each flow control sand screen has an inflow control device (ICD). The downhole completion further comprises a lower sand screen positioned below the plurality of flow control sand screens. The lower sand screen is configured without an ICD and may serve as a sacrificial screen. One or more embodiments of the present disclosure may include one or more lower sand screens configured without an ICD positioned below the plurality of flow control sand screens. For example, there may be as many as two, three, or more lower sand screens configured without an ICD positioned below the plurality of flow control sand screens. A flow restrictor is disposed between the plurality of flow control sand screens and the at least one lower sand screen to enable selective sacrificing, e.g. isolation, of the at least one lower sand screen with respect to the flow control sand screens. That is, according to one or more embodiments of the present disclosure, using the flow restrictor to isolate the at least one lower sand screen effectively shuts off all flow to the at least one lower sand screen such that all flow is directed through the ICDs of the plurality of flow control sand screens. In some embodiments, other types of sand screens could be combined with the plurality of flow control sand screens located above the flow restrictor. Further, in some embodiments, one or more of flow control sand screens and/or lower sand screens may be a port instead of a sand screen. For example, the port may be configured with a housing and a sliding sleeve, where the port is able to be closed. 
     According to an embodiment, a downhole completion is deployed in a borehole, e.g. an open wellbore. The downhole completion comprises at least one flow control sand screen having, for example, an ICD, e.g. a plurality of sand screens with ICDs. The downhole completion also comprises a sand screen located below the at least one flow control sand screen. This lower sand screen does not contain a flow control device such as an ICD. The configuration of the downhole completion enables a fluid displacement process that facilitates open hole displacement of drilling fluid when the downhole completion includes a plurality of inflow (or outflow) restricted sand screens. The downhole completion may comprise a flow restrictor positioned between the flow control sand screens and the lower sand screen. The lower sand screen enables substantial flow, and the flow restrictor may be selectively actuated to sacrifice, e.g. separate, the lower sand screen to restrict flow from this high flow region. 
     Referring generally to  FIG. 1 , an example of a downhole completion  10  is illustrated. In this embodiment, the downhole completion  10  may be configured for use in an open hole borehole, e.g. an open hole wellbore. By way of example, the downhole completion may comprise a packer  12  which may be selectively set against a surrounding borehole wall. An extension  14  may be positioned between the packer  12  and a fluid loss control device  16 , e.g. a flapper valve or other type of fluid loss control device. 
     Beneath the fluid loss control device  16 , the downhole completion  10  includes at least one flow control sand screen  18 . For example, the at least one flow control sand screen  18  may comprise a plurality of sequential flow control sand screens  18  which each have an ICD  20  or ICDs  20  (or other type of flow restriction device). The downhole completion  10  also includes a sand screen without flow restriction devices  24 , e.g. without ICDs  20 , to provide a high flow region between an exterior and an interior of the downhole completion  10 . 
     As illustrated, a flow restrictor  24  may be positioned between the flow control sand screens  18  and the sand screen without flow restrictor  24  to enable selective sacrifice, e.g. isolation, of the sand screen without flow restrictor  24 . The sand screen without flow restrictor  24  may be referred to as a lower sand screen  22 , which means it is positioned farther downhole relative to the at least one flow control sand screen  18 , e.g. the plurality of flow control sand screens  18 . In some embodiments, the downhole completion  10  also comprises a washdown shoe  26 , which may be located below the lower sand screen  22 . 
     According to an operational example, the downhole completion  10  is in the form of a bottom hole assembly, which may be run in a wellbore having a cased section  11  and a lower open hole section  13 , as illustrated in  FIG. 2 . A service tool  28  may be simultaneously run with the downhole completion  10 /bottom hole assembly or subsequently run. By way of example, the service tool  28  may comprise a service string tubing, e.g. washpipe  30 , which extends down through an interior of the plurality of flow control sand screens  18 , the flow restrictor  24 , and the lower sand screen  22 . 
     As illustrated in  FIG. 3 , the packer  12  of the downhole completion  10  may be selectively set by applying a suitable tubing pressure as represented by the arrow illustrated within the work string tubing  31 , e.g. drill pipe. Subsequently, the service tool  28  may be actuated, e.g. moved, to a circulating position. In this position, the service tool  28  positions a crossover port  32  in a gravel packing position and provides a service tool return port  34  above the packer, as illustrated in  FIG. 4 . 
     At this stage, completions fluid may be introduced into an annulus  36  above the packer  12 , as illustrated by the pair of arrows in  FIG. 5 . This stage effectively positions the completions fluid, e.g. fluid train that is to displace the drilling fluid, into the annular area around the top of the packer  12 . It should be noted that in this embodiment, the fluid is illustrated as being pumped from the surface. In other embodiments, however, the fluid could be displaced by the service tool  28  through the gravel pack crossover port  32  before going to the circulating position illustrated in  FIG. 4 . 
     As further illustrated in  FIG. 6 , the completions fluid may then be routed down through the service tool  28  and into the interior of the wash pipe  30 . As the fluid pressure above the packer  12  increases, a flow path for displacement is created and the fluid enters the service tool return ports  34 , passes through the service tool  28  (in the reverse direction to the gravel packing flow), and flows into the wash pipe  30  as illustrated by the arrows in  FIG. 6 . The fluid flow continues down through the wash pipe  30  and exits the wash pipe  30  into the annulus  36  between the wash pipe  30  and the base pipe of the lower sand screen  22 . 
     This fluid continues to flow out through the free-flowing lower sand screen  22 , as illustrated in  FIG. 7 . The lower sand screen  22  has many perforations, so the fluid is able to easily exit the sand screen  22  and flow into the surrounding open hole annulus  36 , as illustrated by arrows in  FIG. 7 . The fluid then flows upwardly through this annulus  36  to continually displace the drilling fluid, as illustrated in  FIG. 8 . As the displacement continues, the fluid will sweep the open hole removing debris and drilling fluids. 
     The debris and drilling fluid will exit the system via the gravel packing crossover port  32  and then flow up through an interior of the work string  31  (drill pipe), as illustrated in  FIG. 9 . This displacement process is continued until a pre-determined amount of fluid has been displaced through the open hole so as to guarantee the system is clean and free of debris. Once this process is completed, the well can be gravel packed as per standard procedures or the service string can be removed. Removal of the service string also can be used to close the flow restrictor  24  and to thus sacrifice/isolate the lower sand screen  22  with respect to fluid flow therethrough. 
     Depending on the parameters of a given application, the flow restrictor  24  may have various configurations. For example, the flow restrictor  24  may comprise a flapper valve controlled by a sliding sleeve, a ball valve, a formation isolation valve, a plug, a single or series of sliding sleeves, or various other flow control devices which may be selectively actuated to restrict or block further inflow (or outflow) through the lower sand screen  22 . It should be noted that in the embodiments illustrated, no polished bore receptacles are shown above the washdown shoe  26  or adjacent the flow restrictor  24 . In other embodiments, however, polished bore receptacles could be included. 
     Referring generally to  FIGS. 10-12 , an example of a flow restrictor  24  is illustrated and is of the type that may be used in the downhole completion  10  between the flow control sand screens  18  and the lower sand screen  22 . The illustrated example effectively provides a modified flapper valve  38  that will close and seal in a flow direction but can be held open by a sleeve  40  to avoid interaction with downhole tools. In normal operations, for example, the flow restrictor  24  is held in an open position by a sleeve  40 , as illustrated in  FIG. 10 , so that the normal operations are not impacted. 
     In  FIG. 10 , a tubing, e.g. a service tool string washpipe  30 /tubing, is illustrated as extending through an interior of the sleeve  40  and an interior of the flow restrictor  24  as the flapper valve  38  is held in an open position via the sleeve  40 . The service tool string  28  may comprise a shifting tool  42  which is used to shift the sleeve  40 , as illustrated in  FIG. 11 . Once the sleeve  40  is shifted to the close position, the flapper valve  38  is able to close, thus restricting or blocking flow as illustrated in  FIG. 12 . By way of example, the shifting tool  42  may be positioned at a lower end of the service tool string  28  so that the sleeve  40  may be shifted and the flow restrictor  24  closed when the service tool string  28  is pulled out of hole. 
     In the specific example illustrated, the flow restrictor  24  is constructed to prevent inflow of fluid through the lower sand screen  22  but other embodiments may be constructed to restrict the inflow of fluid. In some embodiments, the flow restrictor  24  also may be located at other positions along the downhole completion  10 , and it is not restricted to positions above the lowest sand screen  22  or even to positions in the lower completion. 
     Depending on the application, many types of flow restrictors  24  and shifting tools  42  may be used. Additionally, the flow control sand screens  18  may incorporate various types of inflow control devices  20  or other flow restriction devices. Each of the flow control sand screens  18  comprises some type of ICD  20  or other flow control device, but additional sand screens having other configurations also may be located above the flow restrictor  24 . The sand screen  22  located below the flow restrictor  24  may be a single sand screen  24  or a plurality of sand screens  24  and also may have various configurations to facilitate a freer flow of fluid to facilitate the fluid displacement operation. Additionally, the size and configuration of various components, such as the packer  12 , extension  14 , fluid loss control device  16 , flow control sand screens  18 , lower sand screen  22 , washdown shoe  26 , and polished bore receptacle(s), may be adjusted according to the parameters of a given operation and environment. 
     Although a few embodiments of the disclosure have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims.