Patent Publication Number: US-2015060059-A1

Title: Sand control system and methodology employing a tracer

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present document is based on and claims priority to U.S. Provisional Application Ser. No. 61/872,311 filed Aug. 30, 2013, and to U.S. Provisional Application Ser. No. 61/878,169 filed Sep. 16, 2013, both of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     Hydrocarbon fluids such as oil and natural gas are obtained from a subterranean geologic formation, referred to as a reservoir, by drilling a well that penetrates the hydrocarbon-bearing formation. Once a wellbore is drilled, various forms of well completion components, including sand control systems, may be installed in the well. In certain applications, detection systems are employed to help operators analyze the types of well fluids, e.g. oil, water, and/or gas, being produced from specific well zones. In many applications, the detection systems are installed during manufacture of the completion system components and lack adaptability with respect to making adjustments to the detection systems in the field. 
     SUMMARY 
     In general, a system and methodology are provided for facilitating detection of constituents, e.g. oil, water, and gas, in a well fluid as it is produced from a reservoir. The technique employs a screen assembly having a base pipe and a filter media coupled with the base pipe. An access opening is provided in the screen assembly for insertion of a tracer into a region between the base pipe and the filter media. The tracer is then secured in the region between the base pipe and the filter media. The technique enables selection and application of specific, interchangeable tracers while in the field, e.g. at a well site. 
     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 schematic illustration of an example of a well system comprising a screen assembly deployed in a wellbore and having an insertable tracer, according to an embodiment of the disclosure; 
         FIG. 2  is an illustration of another example of a screen assembly having an insertable tracer, according to an embodiment of the disclosure; 
         FIG. 3  is an illustration of another example of a screen assembly having an insertable tracer, according to an embodiment of the disclosure; 
         FIG. 4  is an illustration of another example of a screen assembly having an insertable tracer, according to an embodiment of the disclosure; 
         FIG. 5  is an illustration of another example of a screen assembly having an insertable tracer, according to an embodiment of the disclosure; 
         FIG. 6  is an illustration of an example of a screen assembly having an access opening in an open position for insertion of a tracer, according to an embodiment of the disclosure; 
         FIG. 7  is an illustration of another example of a screen assembly having an insertable tracer, according to an embodiment of the disclosure; 
         FIG. 8  is an illustration of another example of a screen assembly having an insertable tracer, according to an embodiment of the disclosure; and 
         FIG. 9  is an illustration of another example of a screen assembly having an insertable tracer, 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 disclosure herein generally involves a tracer which may be combined with a screen assembly of a downhole well completion system. The tracer may comprise chemical elements or other elements which are released upon sufficient exposure to a specific constituent. In well applications, for example, the tracer may release elements indicative of a specific well fluid constituent, such as oil, water, gas, or another constituent, that may be found in the well fluid produced from a subterranean reservoir. 
     In an embodiment, a well system comprises a tracer which may be selected and readily inserted into a completion component while in the field, e.g. at a well site. In this example, the technique facilitates detection of specific well fluid constituents, e.g. water, in a well fluid as it is produced from a reservoir. The technique employs a screen assembly having a base pipe and a filter media coupled with the base pipe. An access opening is provided in the screen assembly for insertion of a tracer into a region between the base pipe and the filter media. The tracer is then secured in the region between the base pipe and the filter media. In some examples, the tracer is secured by attaching a cover over the access opening. This type of system enables the selection and application of specific tracers for specific screen assemblies while in the field, e.g. at a well site. Accordingly, an operator has great flexibility in customizing well fluid monitoring with respect to the parameters of a specific well fluid, well application, and/or subterranean environment. 
     Referring generally to  FIG. 1 , an example of a well system  20  is illustrated in the form of a well string comprising a sand control completion  22  having at least one screen assembly  24 . The screen assembly  24  comprises a base pipe  26  with a port or a plurality of ports  28  extending radially through a base pipe wall  30  between an exterior and an interior passage  32  of the base pipe  26 . The screen assembly  24  further comprises a filter media  34  disposed about the base pipe  26  in a position so as to filter a flow of well fluid during, for example, a production operation. During production, the well fluid may flow from a reservoir/formation  36  and into a wellbore  38  in which the sand control completion  22  is deployed. From an annulus of the wellbore  38 , the well fluid flows inwardly through filter media  34  and through base pipe wall  30 , via ports  28 , to interior passage  32 . The interior passage  32  directs the well fluid to a surface location or other suitable location. 
     In the example illustrated, the filter media  34  is secured to the base pipe  26  by a friction fitted direct wrap filter media  34  and/or by a housing  40 , e.g. an end ring, which may be positioned at an axial end or ends of the filter media  34 . The filter media  34  may comprise wire wrap, mesh, and/or other filter material for filtering sand from the fluid flowing inwardly from the surrounding formation  36 . The screen assembly  24  further comprises an access opening  42  extending to a region  44  between the base pipe  26  and the filter media  34 . By way of example, the access opening  42  may be formed through housing  40  although the access opening  42  may be positioned at other locations. In some applications, the housing  40  may comprise a standard end ring at one longitudinal end of the filter media  34  and an end ring constructed with the access opening  42  at the other longitudinal end of the filter media  34 . 
     A tracer  46  is sized for insertion through the access opening  42 , as represented by arrow  47 . The tracer  46  is inserted into the region  44  between base pipe  26  and filter media  34  after assembly of the base pipe  26  and the filter media  34 . In this example, the tracer  46  is elongated and may be in the form of an elongated rod or strip  48 . The tracer  46  comprises chemical elements or other elements which are released when sufficiently exposed to a specific fluid or fluids, e.g. oil, water, or gas. 
     During a production operation, for example, well fluid flows from reservoir  36 , into wellbore  38 , through filter media  34 , and into contact with tracer  46  in region  44 . The tracer  46  is formulated and selected so that if a specific constituent is present in the well fluid, e.g. water, chemical elements or other elements are released from the tracer  46 . The tracer elements flow with the inflowing fluid through ports  28  and into interior  32  of base pipe  26 . The well fluid then flows along the interior passage  32  to a surface location or other location with appropriate sensors to detect the presence of the tracer elements. Detection of the tracer elements provides a control system/operator with an indication that the specific constituent is present at a specific well zone along the wellbore  38 . 
     Additionally, a cover  50  may be removably positioned over the access opening  42  so as to ensure sand control is maintained and to secure the tracer  46  in region  44  after insertion of the tracer  46  through access opening  42 . The removable cover  50  may be removably attached to housing  40  or to another suitable component by a variety of techniques. In the illustrated embodiment, removable cover  50  is removably attached by a securing device  54 , such as a threaded fastener, latch, pin or other suitable securing device. In some embodiments, removable cover  50  may be a ring or sleeve having threads along its interior for removable attachment to housing  40  by mating with corresponding threads on housing  40 . 
     Referring generally to  FIG. 2 , another embodiment of screen assembly  24  is illustrated. In this embodiment, housing  40  is in the form of an end ring or end rings  55 , and access opening  42  extends through at least one of the end rings  55 . In the example illustrated, the access opening  42  extends through end ring  55  in a longitudinal/axial direction to facilitate longitudinal insertion of tracer  46  into the region  44  between base pipe  26  and filter media  34 . In this example, cover  50  is in the form of a plug, such as a sand controlling fit plug, threaded cap, bolt, or other suitable type plug. In some applications, a plurality of the access openings  42  may be provided through the housing  40  to enable insertion of a plurality of tracers  46  into region  44 . Access opening(s)  42  also may be a radial opening in housing  40  or a slanted opening oriented at a selected angle between radial and longitudinal orientations. 
     In some applications, longitudinal elements  56  may be arranged in region  44  to create longitudinal channels  58  into which the tracer(s)  46  may be inserted, as illustrated in  FIG. 3 . By way of example, the longitudinal elements  56  may comprise axial rods sized to provide a desired distance between base pipe  26  and filter media  34 . However, in some embodiments the longitudinal elements  56  may comprise transport tubes,  60 , packing tubes  62 , and/or other types of tubes or solid members disposed between base pipe  26  and filter media  34 . In the example illustrated in  FIG. 3 , the housing  40  comprises a torque sleeve  64  which may comprise packing tube nozzles  66  in communication with the corresponding packing tubes  62 . The tracer  46  may be inserted through access opening  42  and positioned between the longitudinal elements  56 . It should be noted that portions of the filter media  34  and outer surface of the torque sleeve  64  have been illustrated as see-through surfaces to better illustrate the longitudinal elements  56  and other internal features. 
     Referring generally to  FIG. 4 , another embodiment of screen assembly  24  is illustrated. In this embodiment, a plurality of standoffs  68  may be positioned between the base pipe  26  and the filter media  34  to maintain separation between the filter media  34  and the base pipe  26 , thus maintaining region  44 . By way of example, the standoffs  68  between base pipe  26  and filter media  34  may comprise longitudinal rods  70  or other suitable standoffs which facilitate movement of fluid along region  44 . The longitudinal rods  70  may be circumferentially spaced around the base pipe  26  to create channels for fluid flow, such as the longitudinal channels  58  described above. Additionally, standoffs  68  may be located between base pipe  26  and housing  40 . 
     In the embodiment illustrated, housing  40  comprises an end ring  72  which engages the filter media  34  and the base pipe  26  to provide structural support and a connection between the filter media  34  and the base pipe  26 . The housing  40  further comprises an access assembly  74  which may comprise a bypass ring  76  and a removable ring assembly  78 . In this example, the removable ring assembly  78  serves as cover  50 . The bypass ring  76  may be connected to end ring  72  by welding or by another suitable fastening mechanism. Additionally, the removable ring assembly  78  may be secured to the bypass ring  76  via a threaded engagement region  80  or by another suitable fastener. The removable ring assembly  78  also may be sealed against an external surface of the base pipe  26  by a suitable seal  82 , such as an O-ring seal. The seal  82  may be formed from, for example, a plastic material or a Teflon material to provide a sand seal for the removable ring assembly  78 . 
     In some embodiments, an inflow control device (ICD)  84  may be disposed in the base pipe  26 , as illustrated in  FIG. 5 . By way of example, the ICD  84  may comprise an orifice, nozzle, and/or tortuous flow path which establishes port  28  for communication with interior  32 . A single ICD  84  or a plurality of ICDs  84  may be used to regulate flow into the interior  32  of base pipe  26 . For example, fluid from reservoir  36  flows through filter media  34 , into region  44 , along the channels between standoffs  68 , into access assembly  74 , through the ICD  84 , and into interior  32  of base pipe  26 . However, the ICD  84  can be positioned at other suitable locations. 
     Referring again to the embodiments of  FIGS. 4 and 5 , the access assembly  74  and removable ring assembly  78 /cover  50  are illustrated in a closed position. However, the removable ring assembly  78  may be disconnected from bypass ring  76  via unthreading removable ring assembly  78  from bypass ring  76  at threaded engagement region  80 . The removable ring assembly  78  is then slid away from the bypass ring  76  to provide the access opening  42 , as illustrated in  FIG. 6 . The tracer  46  may then be inserted through access opening  42  and into region  44  between the standoffs  68 . In some embodiments, the tracer  46  is in the form of elongate strip or rod  48  and constructed with limited flexibility so it may be inserted along region  44  with limited bending. 
     As described above, the tracer  46  may comprise chemical elements or other elements which are released as a specific fluid flows past the tracer  46  and into interior  32  of base pipe  26 . The released elements may be monitored at a surface location of the well or at other suitable locations within the well to provide information related to constituents of the well fluid produced from certain well zones into interior  32 . The easy removability of cover  50 /removable ring assembly  78  enables a variety of tracers  46  to be selected at the well site and positioned between the base pipe  26  and filter media  34 . In other words, the desired tracer  46  may be selected in the field rather than being mounted during a manufacturing process at a manufacturing facility. 
     Referring generally to  FIG. 7 , another embodiment of screen assembly  24  is illustrated. In this embodiment, the removable ring assembly  78  and the bypass ring  76  are provided with tapered ends  86  which meet each other to provide a taper fit. The tapered ends  86  effectively provide a sand control seal between the bypass ring  76  and the removable ring assembly  78  when the removable ring assembly  78  is in the closed position. In this example, the removable ring assembly  78  comprises a stationary ring component  88  and an adjustable ring element  90 . The removable ring assembly  78  may further comprise a locking member  92 , such as a lock nut. 
     The adjustable ring element  90  is removably secured to the stationary ring component  88  by, for example, a threaded region  94  or other suitable fastener. This allows the ring element  90  to be unthreaded with respect to stationary ring component  88  so as to separate the tapered ends  86  and to create access opening  42 . The removable ring assembly  78 /cover  50  may again be closed by threading the adjustable ring element  90  with respect to the stationary ring element  88  so as to move tapered ends  86  together and to close the access opening  42 . The tracer  46  may be inserted through the open access opening  42 , as described above. 
     Referring generally to  FIG. 8 , another embodiment of screen assembly  24  is illustrated. This embodiment is similar to the embodiment illustrated in  FIG. 7 , but the locking member  92  comprises a set screw  96  which is threadably engaged with an opening  98  through adjustable ring element  90 . When the adjustable ring element  90  is moved into engagement with bypass ring  76  via engagement of tapered ends  86 , the set screw  96  may be threaded into engagement with base pipe  26 , as illustrated. The set screw  96  is thus able to securely hold the adjustable ring element  90  in the closed position once tracer  46  is inserted into region  44 . 
     In  FIG. 9 , another embodiment is illustrated in which access opening  42  is in the form of a base pipe opening  100 . The base pipe opening  100  provides an opening through which the tracer  46  may be inserted into region  44  from interior  32  of base pipe  26 . The base pipe opening  100  is sized to accommodate tracer  46  and may be angled through the wall  30  of base pipe  26 . For example, the base pipe opening  100  may be angled from 15° to 60° with respect to a perpendicular opening extending radially through wall  30  of base pipe  26 . In some applications the base pipe opening  100  may be sized 2 to 10 times larger in diameter than base pipe ports  28 . The base pipe opening  100  also may comprise a slot aligned with the base pipe axis to guide the tracer  46  into opening  100 . By way of example, the slot may have a length of 2 to 10 times longer than the diameter of base pipe ports  28  and a width at least as wide as the corresponding tracer  46 . 
     In an operational example, the screen assembly  24  is assembled at a manufacturing facility. However, tracers  46  may be selected and inserted into the corresponding screen assembly  24  at a well site. In some applications, the screen assembly  24  is shipped to a staging area at the well site with the access opening  42  in a closed position. At the staging area and prior to running the screen assembly  26  into the well, an operator can choose to insert a selected tracer  46  into region  44  of screen assembly  26  by opening the access opening  42 . This allows the user to select a specific tracer  46  at the time tracer  46  is to be used in the wellbore  38 . The user simply exposes the access opening  42  by removing cover  50 , e.g removing the removable ring assembly  78 , inserting the desired tracer  46 , and closing the access opening  42 . The screen assembly  24  is then delivered downhole into wellbore  38  via well string system  20 . 
     Depending on the application, many types of sand control completions  22  may be employed in the overall well system  20 . Additionally, the sand control completions  22  may comprise single or multiple screen assemblies  24  having many types of base pipes  26 , filter media  34 , housings  40 , and/or tracers  46 . Additionally, the housings  40  may comprise end rings having a variety of components, connections, and/or features depending on the parameters of a given application. Additionally, many types of standoffs, flow tubing, and/or other components may be positioned in the region  44  between the base pipe  26  and the filter media  44 . 
     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.