Patent Publication Number: US-10316629-B2

Title: Pressure-restrictor plate for a partially loaded perforating gun

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a U.S. national phase under 35 U.S.C. 371 of International Patent Application No. PCT/US2014/042916, titled “Pressure-Restrictor Plate For A Partially Loaded Perforating Gun” and filed Jun. 18, 2014, the entirety of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates generally to devices for use in well systems. More specifically, but not by way of limitation, this disclosure relates to a pressure-restrictor plate for a partially loaded perforating gun. 
     BACKGROUND 
     A well system (e.g., an oil or gas well) can include a wellbore drilled for extracting hydrocarbons from a hydrocarbon reservoir in a subterranean formation. The wellbore can be drilled into or through the hydrocarbon reservoir to provide access to the targeted hydrocarbons. After the wellbore has been drilled, the wellbore is completed. Completing a wellbore can include running a casing into the wellbore to prevent the wellbore from closing on itself. Cement can be pumped into the space between the wall of the wellbore and the casing to seal the wellbore from extraneous fluid and fix the casing in the wellbore. Casing and cementing the wellbore, however, can also seal the wellbore from the hydrocarbon reservoir, inhibiting the extraction of the targeted hydrocarbons. It can be desirable to reestablish access to the hydrocarbon reservoir, typically by using a perforating gun. 
     A perforating gun can include an explosive device that can be positioned in a wellbore adjacent to a hydrocarbon reservoir. When detonated, the perforating gun can pierce portions of the lining (e.g., the casing and cement) of the wellbore, thereby making the hydrocarbon reservoir accessible. Detonating the perforating gun, however, can cause the perforating gun to structurally deform and become trapped in the wellbore. This can render the perforating gun or a wellbore section inoperable. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of a well system that can include a pressure-restrictor plate for a partially loaded perforating gun according to one embodiment of the present disclosure. 
         FIG. 2  is a cross-sectional side view of the partially loaded perforating gun shown in  FIG. 1  according to one embodiment of the present disclosure. 
         FIG. 3  is a side view of a pressure-restrictor plate according to one embodiment of the present disclosure. 
         FIG. 4  is a side view of a pressure-restrictor plate according to another embodiment of the present disclosure. 
         FIG. 5  is a cross-sectional side view of the partially loaded perforating gun shown in  FIG. 1  according another embodiment of the present disclosure. 
         FIG. 6  is an example of a flow chart of a process for using a pressure-restrictor plate for a partially loaded perforating gun according to one embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Certain aspects and features of the present disclosure are directed to a partially loaded perforating gun with a pressure-restrictor plate. The partially loaded perforating gun can include a charge tube for housing explosive charges. The charge tube may not extend through the full length of the partially loaded perforating gun, so that the partially loaded perforating gun is partially loaded, rather than fully loaded. The segment of a partially loaded perforating gun that includes the charge tube is referred to as the “loaded-gun section.” The segment of the partially loaded perforating gun that does not include the charge tube is referred to as the “blank-gun section.” 
     In some embodiments, the partially loaded perforating gun can include a pressure-restrictor plate. The pressure-restrictor plate can include a substantially cylindrical shape. The pressure-restrictor plate can be positioned between the blank-gun section and the loaded-gun section of the partially loaded perforating gun. The pressure-restrictor plate can create a pressure seal between the blank-gun section and the loaded-gun section of the partially loaded perforating gun. In some embodiments, a sealing device (e.g., an O-ring) can be positioned around the outer circumference of the pressure-restrictor plate, for example in a groove. The sealing device can enhance the pressure seal between the loaded-gun section and the blank-gun section of the partially loaded perforating gun. 
     In some embodiments, the pressure-restrictor plate can include an insert. The insert can include a substantially cylindrical shape with a smaller diameter than the diameter of the charge tube. The insert can be positioned within an end of the charge tube, for example, to help align or secure the pressure-restrictor plate between the loaded-gun section and the blank-gun section of the partially loaded perforating gun. 
     In some embodiments, the partially loaded perforating gun can include a rod. One end of the rod can be coupled to the pressure-restrictor plate. The other end of the rod can be coupled to an end plate. The end plate can be, or can be coupled to, a housing of the partially loaded perforating gun. The rod can help position or secure the pressure-restrictor plate between the loaded-gun section and the blank-gun section of the partially loaded perforating gun. 
     In one example, a partially loaded perforating gun can be positioned in a wellbore and adjacent to a hydrocarbon reservoir for piercing a lining (e.g., a casing) of the wellbore to access the hydrocarbon reservoir. The partially loaded perforating gun can include a pressure-restrictor plate. When detonated, the explosive charges in the loaded-gun section of the partially loaded perforating gun can emit one or more pressure waves. The pressure-restrictor plate can prevent the pressure waves from entering the blank-gun section of the partially loaded perforating gun to prevent the perforating gun from collapsing, rupturing, or deforming structurally. In some embodiments, the pressure waves can generate fractures or perforations in the wellbore lining, which can establish a way to access the hydrocarbon reservoir. 
     These illustrative examples are given to introduce the reader to the general subject matter discussed here and are not intended to limit the scope of the disclosed concepts. The following sections describe various additional features and examples with reference to the drawings in which like numerals indicate like elements, and directional descriptions are used to describe the illustrative aspects but, like the illustrative aspects, should not be used to limit the present disclosure. 
       FIG. 1  is a cross-sectional view of a well system  100  for a pressure-restrictor plate for a partially loaded perforating gun according to one aspect of the present disclosure. The well system  100  (e.g., an oil or gas well for extracting fluids from a subterranean formation) includes a wellbore  102 . The wellbore  102  can include a casing  104 . The casing  104  can include multiple connected tubes of the same length or different lengths, or the same diameter or different diameters, positioned in the wellbore  102 . In some embodiments, cement  106  can be disposed between the casing  104  and the wellbore  102 . In other embodiments, the wellbore  102  can include the casing  104  but not the cement  106 . 
     The well system  100  can further include a hydrocarbon reservoir  108 . The hydrocarbon reservoir  108  can include the targeted hydrocarbons. A partially loaded perforating gun  110  can be positioned in the wellbore  102 , for example, adjacent to the hydrocarbon reservoir  108 . In some embodiments, the partially loaded perforating gun  110  can be positioned in the wellbore  102  by, for example, a wireline  112 , a slickline, or a coiled tubing. 
     The partially loaded perforating gun  110  can include explosive charges. The explosive charges can be detonated, for example by a well operator, thereby piercing the lining (e.g., the casing  104  or cement  106 ) of the wellbore  102 . Upon piercing the lining of the wellbore  102 , the hydrocarbons can flow from the hydrocarbon reservoir  108  into the wellbore  102 . The hydrocarbons can be used in or extracted from the well system  100 . 
       FIG. 2  is a cross-sectional side view of the partially loaded perforating gun  110  shown in  FIG. 1  according to one embodiment of the present disclosure. The partially loaded perforating gun  110  can include a housing  202 . A charge tube  204  can be disposed within the housing  202 . The charge tube  204  can include one or more explosive charges  206 , and can position the explosive charges  206  in the partially loaded perforating gun  110 . In some embodiments, the explosive charges  206  can be shaped charges. 
     A pressure-restrictor plate  212  can be positioned adjacent to the charge tube  204  and can fit within the housing  202  of the partially loaded perforating gun  110 . The pressure-restrictor plate  212  can have a substantially cylindrical shape. In some embodiments, the pressure-restrictor plate  212  can include an insert  214 . Although the embodiment shown in  FIG. 2  depicts the insert  214  having a substantially cylindrical shape, the insert  214  can include any other suitable shape. For example, the insert  214  can include a cube shape. The insert  214  can have a smaller diameter than the charge tube  204  and can be positioned within an end of the charge tube  204 . In some embodiments, positioning the insert  214  within the end of the charge tube  204  can help align or secure the pressure-restrictor plate  212  in place. 
     The pressure-restrictor plate  212  and the insert  214  can include one or more holes for communicating a detonation cord  222  between the blank-gun section  210  and the loaded-gun section  208  of the partially loaded perforating gun  110 . The detonation cord  222  can be coupled to the explosive charges  206  for detonating the partially loaded perforating gun  110 . 
     The pressure-restrictor plate  212  can separate and define the boundaries of the loaded-gun section  208  and the blank-gun section  210 . In some embodiments, the pressure-restrictor plate  212  can create a pressure seal between the loaded-gun section  208  and blank-gun section  210  of the partially loaded perforating gun  110 . The pressure-restrictor plate  212  can include any suitable material. An example of a suitable material is metal, such as steel. In some embodiments, one or more sealing devices  216 , such as O-rings, can be coupled to the pressure-restrictor plate  212  for creating or enhancing the pressure seal between the loaded-gun section  208  and blank-gun section  210 . Unlike with traditional partially loaded perforating guns, upon detonating the partially loaded perforating gun  110 , the pressure-restrictor plate  212  can prevent pressure waves from the loaded-gun section  208  from entering the blank-gun section  210 . This can prevent the partially loaded perforating gun  110  from collapsing, rupturing, or deforming structurally. 
     The partially loaded perforating gun  110  can include a rod  218 . The rod  218  can include any suitable material. An example of a suitable material is metal, such as steel. In some embodiments, one end  224  of a rod  218  can be coupled to the pressure-restrictor plate  212  and the other end  226  of the rod  218  can be coupled to an end plate  220 . The end plate  220  can be a part of, or can be positioned within, a housing  202  of the partially loaded perforating gun  110 . The rod  218  can be coupled to the pressure-restrictor plate  212  or the end plate  220  by, for example, a threaded connection, an insert, or by welding. The rod  218  can be hollow in some examples. In some embodiments, the length of the rod  218  can be adjustable. For example, the length of the rod  218  can be selectively modified for positioning the pressure-restrictor plate  212  in the partially loaded perforating gun  110 . The detonation cord  222  can be wrapped around the rod  218  or disposed within the rod  218  (e.g., if the rod  218  is hollow) for communicating a detonation signal to the explosive charges  206 . 
     Although the embodiment shown in  FIG. 2  depicts the blank-gun section  210  positioned in the longitudinal bottom of the partially loaded perforating gun  110  and the loaded-gun section  208  positioned in the longitudinal top of the partially loaded perforating gun  110 , the positions of the blank-gun section  210  and the loaded-gun section  208  can be switched. For example, the blank-gun section  210  can be positioned in the longitudinal top of the partially loaded perforating gun  110  and the loaded-gun section  208  can be positioned in the longitudinal bottom of the partially loaded perforating gun  110 . Further, in some embodiments, the partially loaded perforating gun  110  can include multiple blank-gun sections  210 , multiple loaded-gun sections  208 , multiple pressure-restrictor plates  212 , multiple rods  218  (described further with respect to  FIG. 5 ), or multiples of any combination of these. 
       FIG. 3  is a side view of a pressure-restrictor plate  212  according to one embodiment of the present disclosure. As described above, in some embodiments, the pressure-restrictor plate  212  can include a cylindrical shape or a circular shape. Further, the pressure-restrictor plate  212  can include an insert  214 . The insert  214  can include a cylindrical shape, or any other suitable shape. Further, in some embodiments, one or more sealing devices  216  can be coupled to the pressure-restrictor plate  212 , such as being coupled to the outer circumference of the pressure-restrictor plate  212 . The sealing devices  216  can create or enhance a pressure seal between the blank-gun section and the loaded-gun section of the partially loaded perforating gun. In some embodiments, the pressure-restrictor plate can include a channel or groove (for example, the groove  402  shown in  FIG. 4 ). The channel or groove can be positioned around the outer circumference of the pressure-restrictor plate  212 , for example, for receiving the sealing device  216 . 
     In some embodiments, a rod (not shown) can be coupled to the bottom  302  of the pressure-restrictor plate  212 , for example, to the cross-sectional center of the bottom  302  of the pressure-restrictor plate  212 . Further, in some embodiments, the pressure-restrictor plate  212  and the insert  214  can include a hole  304 , for example, for threading a detonation cord between the blank-gun section and the loaded-gun section of the partially loaded perforating gun. Although the hole  304  is depicted in  FIG. 3  as including a circular cross-sectional end shape, in other embodiments, the hole  304  can include any suitable shape. Some examples of a suitable shape can include a rectangular, square, oval, or a triangular shape. 
       FIG. 5  is a cross-sectional side view of the partially loaded perforating gun shown in  FIG. 1  according another embodiment of the present disclosure. In this example, the partially loaded perforating gun  110  includes multiple blank-gun sections  210  and multiple loaded-gun sections  208 . The partially loaded perforating gun  110  can include any number of loaded-gun sections  208  and any number of blank-gun sections  210 . 
     The partially loaded perforating gun  110  can include multiple pressure restrictor plates  212 . A pressure-restrictor plate  212  can be positioned for separating each of the multiple blank-gun sections  210  from each of the multiple loaded-gun sections  208 . The pressure-restrictor plates  212  can perform substantially the same functions and have substantially the same characteristics as the pressure-restrictor plate  212  described with respect to  FIGS. 2-4 . In some embodiments, one or more pressure-restrictor plates  212  can include an insert  214 . The insert  214  can be positioned within an end of a charge tube  204  in a loaded-gun section  208 . Further, in some embodiments, the one or more pressure-restrictor plates  212  can include a hole, for example, for communicating a detonation cord between a blank-gun section  210  and a loaded-gun section  208  of the partially loaded perforating gun. 
     The partially loaded perforating gun  110  can also include multiple rods  218 . In some embodiments, a rod  218  can be coupled to a pressure-restrictor plate  212  on one end, and to an end plate  220  on the other end. The end plate  220  can be a part of, or be positioned within, the housing  202  of the partially loaded perforating gun  110 . In other embodiments, a rod  218  can be coupled on each end to a different pressure-restrictor plate  212 . For example, one end of the rod  218  can be coupled to one pressure-restrictor plate  212  and another end of the rod  218  coupled to another pressure-restrictor plate  212 . 
       FIG. 6  is an example of a flow chart of a process for using a pressure-restrictor plate for a partially loaded perforating gun according to one embodiment of the present disclosure. 
     In block  602 , a pressure-restrictor plate creates a pressure seal between a blank-gun section and a loaded-gun section of a partially loaded perforating gun. The pressure-restrictor plate can be positioned between the blank-gun section and the loaded-gun section of the partially loaded perforating gun. In some embodiments, the pressure-restrictor plate can be positioned within the blank-gun section and adjacent to the loaded-gun section of the partially loaded perforating gun. Further, in some embodiments, the pressure-restrictor plan can include a groove for receiving a sealing device (e.g., an O-ring) for enhancing the pressure seal between the blank-gun section and the loaded-gun section of the partially loaded perforating gun. The partially loaded perforating gun can be positioned in a wellbore. 
     In block  604 , a pressure wave is generated in the loaded-gun section. The pressure wave can be generated by detonating one or more explosive charges in the loaded-gun section. 
     In some embodiments, an electrical signal or other ignition source (e.g., fire) can be transmitted to one or more detonation cords coupled to one or more explosive charges within the partially loaded perforating gun. For example, an electrical signal can be transmitted from a power source via a wireline to the one or more detonation cords within the loaded-gun section. The electrical signal or other ignition source can travel through the detonation cord, which can cause the one or more explosive charges to detonate. Detonating the one or more explosive charges can generate one or more pressure waves in the loaded-gun section of the partially loaded perforating gun. 
     In block  606 , the pressure-restrictor plate can prevent the pressure wave from entering the blank-gun section of the partially loaded perforating gun. The pressure-restrictor plate can create a pressure seal to prevent the pressure wave from entering the blank-gun section. Preventing the pressure wave from entering the blank-gun section can prevent the perforating gun from collapsing, rupturing, or deforming structurally. 
     In some aspects, a system for a pressure-restrictor plate for a partially loaded perforating gun is provided according to one or more of the following examples. 
     Example #1 
     An assembly can include a charge tube that can be positioned in a loaded-gun section of a partially loaded perforating gun. The assembly can also include a pressure-restrictor plate that can be positioned between a blank-gun section of the partially loaded perforating gun and adjacent to the charge tube. The assembly can further include a rod for securing the pressure-restrictor plate in a position, the rod having a first end that can be coupled to the pressure-restrictor plate and a second end that can be coupled to an end plate positioned within the partially loaded perforating gun. 
     Example #2 
     The assembly of Example #1 may feature the partially loaded perforating gun including a perforating gun in which the charge tube does not extend a full longitudinal length of the perforating gun. 
     Example #3 
     The assembly of any of Examples #1-2 may feature a second pressure-restrictor plate, a second blank-gun section, and a second rod. The second rod can be coupled to the second pressure-restrictor plate and can be positioned within the second blank-gun section. 
     Example #4 
     The assembly of any of Examples #1-3 may feature an O-ring positioned in a groove around an outer circumference of the pressure-restrictor plate. 
     Example #5 
     The assembly of any of Examples #1-4 may feature the pressure-restrictor plate including a hole for communicating a detonation cord between the blank-gun section and the loaded-gun section. 
     Example #6 
     The assembly of any of Examples #1-5 may feature an insert coupled to the pressure-restrictor plate for aligning or securing the pressure-restrictor plate adjacent to the charge tube. 
     Example #7 
     The assembly of Example #6 may feature the insert being positionable within an end of the charge tube. 
     Example #8 
     The assembly of any of Examples #1-7 may feature the charge tube including multiple shaped charges. 
     Example #9 
     The assembly of any of Examples #1-8 may feature the pressure-restrictor plate positioned for separating the blank-gun section from the loaded-gun section. 
     Example #10 
     The assembly of any of Examples #1-9 may feature the pressure-restrictor plate positioned for creating a pressure seal between the blank-gun section and the loaded-gun section. 
     Example #11 
     An assembly can include a loaded-gun section of a partially loaded perforating gun. The loaded-gun section can include multiple explosive charges. The assembly can also include a pressure-restrictor plate. The pressure-restrictor plate can be positioned for separating the loaded-gun section from a blank-gun section of the partially loaded perforating gun and generating a pressure seal between the loaded-gun section and the blank-gun section. 
     Example #12 
     The assembly of Example #11 may feature the partially loaded perforating gun including a perforating gun in which the loaded-gun section does not extend a full longitudinal length of the perforating gun. 
     Example #13 
     The assembly of any of Examples #11-12 may feature an O-ring positioned in a groove around an outer circumference of the pressure-restrictor plate. 
     Example #14 
     The assembly of any of Examples #11-13 may feature the pressure-restrictor plate including a hole for communicating a detonation cord between the blank-gun section and the loaded-gun section. 
     Example #15 
     The assembly of any of Examples #11-14 may feature an insert coupled to the pressure-restrictor plate for aligning or securing the pressure-restrictor plate adjacent to the charge tube. 
     Example #16 
     The assembly of Example #15 may feature the insert being positionable within an end of the charge tube. 
     Example #17 
     The assembly of any of Examples #11-16 may feature a rod coupled to the pressure-restrictor plate and an end plate for securing the pressure-restrictor plate in a position, the end plate disposed within a housing of the partially-loaded perforating gun. 
     Example #18 
     The assembly of any of Examples #11-17 may feature multiple pressure-restrictor plates, multiple blank-gun sections, and multiple rods. Each of the multiple rods can be coupled to at least one of the multiple pressure-restrictor plates and can be positioned within one of the multiple blank-gun sections. 
     Example #19 
     A method can include pressure sealing, by a pressure-restrictor plate, a blank-gun section of a partially loaded perforating gun from a loaded-gun section of the partially loaded perforating gun. The partially loaded perforating gun can be positioned in a wellbore. The method can also include generating a pressure wave in the loaded-gun section. The method can further including preventing, by the pressure-restrictor plate, the pressure wave from entering the blank-gun section. 
     Example #20 
     The method of Example #19 may feature generating, by the pressure wave, multiple perforations in the lining of the wellbore. 
     The foregoing description of certain embodiments, including illustrated embodiments, has been presented only for the purpose of illustration and description and is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Numerous modifications, adaptations, and uses thereof will be apparent to those skilled in the art without departing from the scope of the disclosure.