Patent Publication Number: US-11391127-B1

Title: Adjustable perforating gun orientation system

Description:
BACKGROUND 
     After drilling a wellbore in a subterranean formation for recovering hydrocarbons such as oil and gas lying beneath the surface, a casing string may be fed into the wellbore. Generally, the casing string protects the wellbore from failure (e.g., collapse, erosion) and provides a fluid path for hydrocarbons during production. Traditionally the casing string is cemented to the wellbore. To access the hydrocarbons for production, a perforating gun system may be deployed into the casing string via a tool string. The tool string (e.g., a tubing string, wireline, slick line, coil tubing) lowers the perforating gun system into the casing string to a desired position within the wellbore. Once the perforating gun system is in position such that shaped charges are disposed adjacent to a subterranean formation having hydrocarbons, the shaped charges are detonated. The detonation perforates the casing string, the cementing, and the subterranean formation such that hydrocarbons may flow into the casing string via the perforation. 
     Some perforating gun systems are configured to aim the shaped charges in particular directions to improve production and/or avoid particular portions of the subterranean formation. Indeed, some perforating gun systems are configured to dynamically adjust an orientation of the shaped charges. That is a rotating member holding the shaped charges is configured to rotate within the perforating gun due to gravitational forces based on a center gravity of the rotating member. To aim the shaped charges in particular directions, the shaped charges and/or portions of the rotating members are configured (e.g., positioned, adjusted, etc.) before installing the rotating member in the perforating gun, such that the dynamical adjustment moves the shaped charges into desired orientations within the wellbore. 
     However, in these traditional systems, re-positioning and/or adjusting the shaped charges to modify the orientations of the shaped charges within the wellbore after initial installation requires disassembly of the perforating guns. That is, the rotating members and other perforating gun components must be removed from the perforating gun bodies to provide access to re-position and/or adjust the shaped charge holders, replace the rotating member, etc. Unfortunately, removing rotating members and other perforating gun components to adjust the orientations of the shaped charges is costly, time consuming, and may hinder efficiency of production operations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These drawings illustrate certain aspects of some of the embodiments of the present disclosure and should not be used to limit or define the method. 
         FIG. 1  illustrates a side elevation, partial cross-sectional view of an operational environment for a drilling system in accordance with one or more embodiments of the disclosure. 
         FIGS. 2A and 2B  illustrate respective cross-sectional views of the charge tube of the perforating gun system, in accordance with one or more embodiments of the disclosure. 
         FIG. 3  illustrates a cross-sectional view of the perforating gun system, in accordance with some embodiments of the present disclosure. 
         FIG. 4  illustrates a perspective view of the weighted feature secured to the charge tube of the perforating gun system, in accordance with some embodiments of the present disclosure. 
         FIG. 5  illustrates a cross-sectional view of a compliant housing for securing the weighted feature to the charge tube, in accordance with some embodiments of the present disclosure. 
         FIG. 6  illustrates a perspective view of an adjustment arm for adjusting the angular orientation of the weighted feature, in accordance with some embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Provided are systems for perforating a subterranean formation and, more particularly, example embodiments may include a perforating gun system configured to dynamically adjust an orientation of a charge tube, via gravitational forces, such that shaped charges in the perforating gun system shoot in desired directions upon detonation. Without disassembling the perforating gun system, a perforating gun system may be configured modify a center of gravity of the charge tube, to change a resting orientation of the charge tube resulting from the dynamical adjustment of the charge tube. In particular, the perforating gun system may be configured to modify the center of gravity of the charge tube while the charge tube is disposed within and rotatably mounted to a gun body of the perforating gun system. 
       FIG. 1  illustrates a side elevation, partial cross-sectional view of an operational environment for a drilling and completion system in accordance with one or more embodiments of the disclosure. It should be noted that while  FIG. 1  generally depicts a land-based drilling and completion assembly, those skilled in the art will readily recognize that the principles described herein are equally applicable to subsea drilling and completion operations that employ floating or sea-based platforms and rigs, without departing from the scope of the disclosure. As illustrated, the drilling and completion assembly  100  includes a platform  102  that supports a derrick  104  having a traveling block  106  for raising and lowering a tool string  108 . The tool string  108  includes, but is not limited to, a work string  110 , a perforating gun system  112 , and any other suitable tools, as generally known to those skilled in the art. While not shown, tubing string, wireline, slick line, and/or coil tubing may be used instead of convention work string  110  for supporting the perforating gun system  112 . 
     The work string  110  is configured to lower the perforating gun system  112  into a wellbore  114 . As illustrated, the wellbore  114  may be lined with casing  116  cemented to a wellbore wall  118 . The casing  116  is configured to protect the wellbore  114  from failure (e.g., collapse, erosion) and to provide a fluid path for hydrocarbons during production. To access the hydrocarbons, the work string  110  lowers the perforating gun system  112  to a position such that shaped charges  120  are disposed adjacent to a subterranean formation  122  having the hydrocarbons, and the perforating gun system  112  detonates the shaped charges  120 . In some embodiments, the shaped charges  120  may be sequentially detonated by the perforating gun system  112  in a downhole to uphole direction  124  or an uphole to downhole direction  126 . The detonations perforate the casing  116 , the cementing, and the subterranean formation  122  in the respective paths of the shaped charge detonations such that hydrocarbons may flow into the casing  116  string via the perforations. 
     In the illustrated embodiment, the wellbore  114  has a vertical portion  128  and a horizontal portion  130  with the perforating gun system  112  being disposed in the horizontal portion  130 . The perforating gun system  112  includes a charge tube  132  (e.g., a rotating member holding the shaped charges  120 ) rotatably mounted within a gun body  134  of the perforating gun system  112 . As set forth in greater detail below, the perforating gun system  112  is configured to dynamically adjust the orientation of a charge tube  132  to the resting orientation  136  based on a center of gravity  138  of a charge tube  132  (shown in  FIG. 2A ). That is, with the perforating gun system  112  disposed in the horizontal portion  130  of the wellbore  114 , the charge tube  132  is biased by gravity to rotate (e.g., dynamically adjusted) until the center of gravity  138  of the charge tube  132  is disposed directly below a rotational axis  140  of the charge tube  132  (e.g., the resting orientation  136 ). Although the illustrated embodiment shows the perforating gun system  112  disposed in the horizontal portion  130 , the perforating gun system  112  may be configured to dynamically adjust the orientations of the shaped charges  120  in any non-vertical portion of the wellbore  114 . 
       FIGS. 2A and 2B  illustrate respective cross-sectional views of the charge tube  132  of the perforating gun system  112 , in accordance with one or more embodiments of the disclosure. In some embodiments, the shaped charges  120  are fixed to the charge tube  132 . Thus, to aim the shaped charges  120  in desired directions  214  (i.e., move the shaped charges  120  into desired orientations with respect to the wellbore  114 ) the perforating gun system  112  is configured to modify the center of gravity  138  of the charge tube  132  to change the resting orientation  136  of the charge tube  132  resulting from the dynamical adjustment (e.g., biasing the charge tube  132  via gravity to rotate about the rotational axis  140  until the center of gravity  138  is disposed directly below the rotational axis  140  of the charge tube  132 ). As the shaped charges  120  are fixed to the charge tube  132 , changing the resting orientation  136  of the charge tube  132  moves the orientation of the shaped charges  120  with respect to the wellbore  114 . For example, in a first position  200  shown in  FIG. 2A , the center of gravity  138  of the charge tube  132  may be disposed ninety degrees counter-clockwise from the shaped charge  120  such that the shaped charge  120  will be directed in a lateral left direction  202  when the charge tube  132  dynamically adjusts from the shown orientation to the resting orientation  136  with the center of gravity  138  disposed directly below the rotational axis  140  of the charge tube  132 . In a second position  204  shown in  FIG. 2B , the center of gravity  138  of the charge tube  132  may be adjusted such that it is disposed one-hundred and eighty degrees counter-clockwise from the shaped charge  120  such that the shaped charge  120  is directed in an upward direction  206  when the charge tube  132  is in the resting orientation  136 . Thus, the perforating gun system  112  is configured to aim the shaped charges  120  in the desired directions  214  by selectively adjusting the center of gravity  138  of the charge tube  132  with respect to the shaped charges  120 . 
     In some embodiments, the perforating gun system  112  includes a weighted feature  208  configured to adjust the center of gravity  138  of the charge tube  132 . That is, the additional mass from the weighted feature  208  is configured to change the center of gravity  138  (e.g., center of mass) of the charge tube  132  based on a position of the weighted feature  208  with respect to the charge tube  132 . The weighted feature  208  may be rigidly attached to the charge tube  132  to add mass to a particular portion of the charge tube  132 . Attaching the weighted feature  208  to the charge tube  132  at a particular position may aim the shaped charge  120  in a corresponding direction. Indeed, an aimed direction  210  of the shaped charge  120  is based at least in part on an angular orientation of the shaped charge  120  with respect to the center of gravity  138  of the charge tube  132 . As such, selectively adjusting the angular orientation  212  of the weighted feature  208  with respect to the shaped charge  120  may move the aimed direction  210  of the shaped charge  120  to the desired direction  214 . 
     In some embodiments, the weighted feature  208  is attached to a radially outward portion of the charge tube  132  proximate an outer diameter of the charge tube  132 . A radial positioning of the weighted feature  208  may affect a radial position of the center of gravity  138  of the charge tube  132 . Positioning the weighted feature  208  on the charge tube  132  to move the center of gravity  138  radially outward may increase the moment arm, which may increase the moment (e.g., torque) on the charge tube  132  for rotating the charge tube  132  to the resting orientation  136 . The weighted feature  208  may be positioned to generate more torque to overcome forces (e.g., friction, etc.) resisting rotation of the charge tube  132  with respect to the gun body  134 . Additionally, or alternatively, the mass of the weighted feature  208  may be increased to increase the torque on the charge tube  132 . 
     Moreover, the weighted feature  208  is configured to removably attached to the charge tube  132  such that the weighted feature  208  may be moved to various positions on the charge tube  132 . As set forth above, moving the weighted feature  208  adjust the center of gravity  138  of the charge tube  132  to aim the shaped charges  120  in the desired direction  214 . 
       FIG. 3  illustrates a cross-sectional view of the perforating gun system  112 , in accordance with some embodiments of the present disclosure. As set forth above, the perforating gun system  112  includes the gun body  134  (e.g. gun carrier). The gun body  134  is configured to house the charge tube  132 . In the illustrated embodiment, the charge tube  132  includes a generally cylindrical shape. However, the charge tube  132  may include any suitable shape that permits free rotation of the charge tube  132  within an interior portion  300  of gun body  134 . For example, the charge tube  132  may include an elliptical profile so long as the charge tube  132  may freely rotate within the gun body  134  without contacting an interior surface  302  of the gun body  134 . Contact between the charge tube  132  and gun body  134  may hinder or prevent rotation of the charge tube  132 . 
     In some embodiment, the perforating gun system  112  may include a plurality of mounting devices  304  configured to rotatably mount the charge tube  132  within the gun body  134 . The mounting devices  304  may radially secure the charge tube  132  within the gun body  134  to prevent the exterior surface  306  of the charge tube  132  from contacting the interior surface  302  of the gun body  134 . Further, the mounting devices  304  may include roller elements or bearings  308  configured to permit free rotation of the charge tube  132  with respect to the gun body  134 . The bearings  308  may include ball bearings, roller bearings, plain bearings, or any other suitable type of bearing. In the illustrated embodiment, the plurality of bearings  308  include a first set of bearings  310  secured to an interior portion  300  of the gun body  134  proximate a first axial end  314  of the gun body  134  and a second set of bearings  312  secured to the interior portion  300  of the gun body  134  proximate the second axial end  316  of the gun body  134 . In some embodiment, the perforating gun system  112  may include additional mounting devices  304  to further secure the charge tube  132 . For example, the perforating gun system  112  may include thrust bearings configured to axially secure the charge tube  132  with respect to the gun body  134 . 
     As set forth above, the perforating gun system  112  includes the weighted feature  208  configured to adjust the center of gravity  138  of the charge tube  132 . In the illustrated embodiment, the weighted feature  208  is disposed between a first axial end  320  of the charge tube  132  and the first axial end  314  of the gun body  134 . Positioning the weighted feature  208  between the first axial end  320  of the charge tube  132  and the first axial end  314  of the gun body  134  may provide access to the weighted feature  208  via the first axial end  314  of the gun body  134 . As set forth in more detail below, the positioning (e.g., angular orientation  212  and/or radial position) of the weighted feature  208  with respect to the charge tube  132  may be adjusted from the first axial end  314  of the gun body  134 . That is, to adjust the weighted feature  208 , the first axial end  314  of the charge tube  132  may be removed such that the weighted feature  208  may be re-positioned while the charge tube  132  is disposed within the gun body  134 . In some embodiments, the weighted feature  208  may be re-positioned without removing the first axial end  314  of the gun body  134 . In some embodiments, the weighted feature  208  is disposed at least partially radially outward from the charge tube  132  along a portion of the charge tube  132 . The weighted feature  208  may be positioned in any suitable position with respect to the charge tube  132  such that the weighted feature  208  may be re-positioned without removing the charge tube  132  from the gun body  134 . 
     Moreover, the perforating gun system  112  also includes the at least one shaped charge  120 . As set forth above, the shaped charge  120  may be mounted within the charge tube  132 . The at least one shaped charge  120  is configured to detonate to perforate the casing  116 , the cementing, and the subterranean formation  122 . The perforating gun system  112  further includes a detonating device  322  configured to initiate detonation of the shaped charges  120 . The detonating device  322  may include a detonating cord  324  connected to each shaped charge  120  mounted within the charge tube  132 . 
       FIG. 4  illustrates a perspective view of the weighted feature  208  configured to secure to the charge tube  132  of the perforating gun system  112 , in accordance with some embodiments of the present disclosure. As set forth above, the charge tube  132  is disposed within and rotatably mounted to the gun body  134  via the plurality of bearings  308 . The charge tube  132  has at least one shaped charge  120 . Further, the perforating gun system  112  includes the weighted feature  208  that may be removably or adjustably attached to the charge tube  132  in one of a plurality of angular orientations. The weighted feature  208  may be re-positioned to adjust the center of gravity  138  of the charge tube  132  such that gravity will cause the charge tube  132  to rotate to a corresponding phasing angle (e.g., resting orientation  136 ). 
     In some embodiments, the charge tube  132  includes a receiving feature  400  disposed at the first axial end  320  of the charge tube  132 . In the illustrated embodiment, the receiving feature  400  includes a plurality of axial slots  402  disposed in a circular pattern around the first axial end  320  of the charge tube  132 . However, the receiving feature  400  may include any suitable feature configured to receive a corresponding attachment feature  404 . The axial slots  402  may be angularly offset  406  by a particular angle. For example, the axial slots  402  may be angularly offset  406  from each other by forty-five degrees such that the receiving feature  400  includes a set of eight axial slots  402  angularly offset  406  from each other around the axial end of the charge tube  132 . However, the receiving feature  400  may include any number of axial slots  402 . Further, in some embodiments, the axial slots  402  of the receiving feature  400  may be radially offset (not shown) from each other. Moreover, each axial slot  402  may include a circular bore  408  in the first axial end  320  of the charge tube  132 . Alternatively, the axial slots  402  may include other bores with alternative shapes (e.g., rectangular, hexagonal, star, cross, etc.). Further, each axial slot  402  of the receiving feature  400  may include a lip feature  410  configured to secure the attachment feature  404  within the respective axial slot  402 . For example, the lip feature  410  may be configured to provide a snap-fit between the receiving feature  400  and the attachment feature  404 . In some embodiments, the axial slots  402  may be tapped such that they are configured to receive corresponding threaded portions of the attachment feature  404 . 
     The attachment feature  404  may be mounted to the weighted feature  208  and configured to interface with the receiving feature  400  to adjustably attach to the receiving feature  400 . The attachment feature  404  may be configured to disengage from the receiving feature  400  in a first angular position and re-engage with the receiving feature  400  in another angular position (e.g., a second angular position) to adjust the angular orientation of the weighted feature  208  with respect to the charge tube  132 . As set forth above, the attachment feature  404  may be configured disengage and re-engage with the receiving feature  400  while the charge tube  132  is disposed within and rotatably mounted to the gun body  134 . To disengage the attachment feature  404 , an axial force may be applied to the weighted feature  208  and/or attachment feature  404  in an axial outward direction  414  away from the charge tube  132  and/or receiving feature  400 . In some embodiments, a tool may be secured to the weighted feature  208  to apply the axial force. However, the snap-fit may be configured such that the attachment feature  404  may be disengaged via an operator manually pulling on the weighted feature  208  and/or attachment feature  404 . To re-engage the attachment feature  404 , the weighted feature  208  may be aligned to the desired angular orientation  212  and an axial force may be applied to the weighted feature  208  and/or attachment feature  404  in an axial inward direction  416  toward the charge tube  132 . 
     In the illustrated embodiment, the attachment feature  404  includes a plurality of pins  418  mounted to an axially inner end  420  of the weighted feature  208 . In some embodiments, the pins  418  may be welded, brazed, threaded, or otherwise fastened to the weighted feature  208 . Alternatively, the plurality of pins  418  may be integral to the weighted feature  208 . That is, the weighted feature  208  may be cast to have the plurality of pins  418 , the plurality of pins  418  may be machined into the axial inner end  420  of the weighted feature  208 , etc. Moreover, as set forth above, the plurality of pins  418  may be configured to interface with the plurality of axial slots  402  of the receiving feature  400  to secure the weighted feature  208  to the charge tube  132  at a particular angular orientation  212 . In the illustrated embodiment, the pins  418  are cylindrically shaped to interface with corresponding cylindrical, axial slots  402  of the receiving system. However, the pins  418  may include any suitable shaped configured to interface with the plurality of axial slots  402  of the receiving system. Moreover, the plurality of pins  418  may include recessed portions configured to interface with the lip feature  410  such that the plurality of pins  418  may snap-fit within the axial slots  402  of the receiving feature  400 . 
     The plurality of pins  418  may be disposed in a similar pattern, with respect to the axial slots  402 , around at least a portion of the axial inner end  420  of the weighted feature  208 . Further, the plurality of pins  418  may include a same angular offset and/or radial offset between pins  418  as with the plurality of axial slots  402 . Alternatively, the pins  418  may be angularly offset from each other by a multiplicative angle with respect to the offset angle of the plurality of axial slots  402 . For example, the plurality of pins  418  may be offset from each other by substantially ninety degrees in an embodiment having the plurality of axial slots  402  offset by forty-five degrees. As such, a first pin  422  of the plurality of pins  418  may be engage in any of the plurality of axial slots  402  of the receiving feature  400  as the remaining pins  418  may always align with other axial slots  402  of the receiving feature  400  when the first pin  422  is engaged. Accordingly, the angular orientation of the weighted feature  208  may be adjusted with respect to the charge tube  132  by indexing the pins  418  with respect to the axial slots  402 . For example, the plurality of axial slots  402  may be offset from each other by forty-five degrees. Thus, indexing the pins  418  to adjacent axial slots  402  in a counterclockwise direction may rotate the weighted feature  208  forty-five degrees with respect to the charge tube  132 . The receiving feature  400  may include additional axial slots  402  to increase the resolution for adjusting the weighted feature  208  with respect to the charge tube  132 . 
     Moreover, in the illustrated embodiment, the weighted feature  208  includes a semi-cylindrical shape. However, the weighted feature  208  may include any suitable shape having a center of mass that is radially offset from the rotational axis  140  of the charge tube  132  when attached. Further, the weighted feature  208  may include a steel material. Alternatively, the weighted feature  208  may include any suitable material (e.g., lead, tungsten, etc.) having sufficient weight for effectively adjusting the center of gravity  138  of the charge tube  132 . 
       FIG. 5  illustrates a cross-sectional view of a compliant housing for securing the weighted feature  208  to the charge tube  132 , in accordance with some embodiments of the present disclosure. As set forth above, the perforating gun system  112  includes the charge tube  132  that is configured to house shaped charges  120 , disposed within the gun body  134 , and rotatably mounted to the gun body  134  via bearings  308 . Further, the charge tube  132  may include the receiving feature  400  configured to receive the attachment feature  404  such that the weighted feature  208  may removably or adjustably attach the to the charge tube  132 . 
     In the illustrated embodiment, the receiving feature  400  includes plurality of radial slots  500  disposed proximate the first axial end  320  of the charge tube  132 . The radial slots  500  may extend at least partially into an outer wall  502  of the charge tube  132  in a substantially radially outward direction  504 . In some embodiments, the radial slots  500  may extend through the outer wall  502  of the charge tube  132 . The radial slots  500  may be disposed in a circular pattern around an inner surface  506  of the outer wall  502  proximate the first axial end  320  of the charge tube  132 . The radial slots  500  may be angularly offset from each other by a particular angle. For example, the radial slots  500  may be angularly offset from each other by forty-five degrees such that the receiving feature  400  includes a set of eight radial slots  500  angularly offset from each other around the inner surface  506  of the outer wall  502  of the charge tube  132 . In some embodiments, the receiving feature  400  includes an even number of slots, with each radial slot  500  having a corresponding radial slot angularly offset  406  by one-hundred and eighty degrees. However, the receiving feature  400  may include any number of radial slots  500 . Further, in some embodiments, the radial slots  500  of the receiving feature  400  may be axially offset from each other (not shown) such that the position of the weighted feature  208  may be axially adjusted within the gun body  134 . Moreover, each radial slot  500  may include a circular bore configured to receive a corresponding attachment feature  404 . Alternatively, the radial slots  500  may include alternative bore shapes (e.g., rectangular, hexagonal, star, cross, etc.). 
     As illustrated, the attachment feature  404  may include a compliant housing  506  secured to the weighted feature  208 . In some embodiments, the weighted feature  208  may be attached to an exterior portion  508  of the compliant housing  506 . Alternatively, the weighted feature  208  may be housed within an interior portion  510  of the compliant housing  506 . The compliant housing  506  is configured to mount to the receiving feature  400  to removably or adjustably attach the weighted feature  208  to the charge tube  132 . In the illustrated embodiment, the compliant housing  506  includes a plurality of radial pins  512  (e.g., a first radial pin  514  and a second radial pin  516 ) configured to interface with the radial slots  500  of the receiving feature  400  to secure the weighted feature  208  to the charge tube  132  at a particular angular orientation with respect to the charge tube  132 . The plurality of radial pins  512  may extend from the compliant housing  506  in the radially outward direction  504  with respect to the rotational axis  140  of the charge tube  132 . At least an end portion  518  of each of the radial pins  512  may include a substantially cylindrical shape configured to interface with corresponding cylindrical, radial slots  500  (e.g., a first radial slot  520  and a second radial slot  522 ) of the receiving feature  400 . However, the plurality of radial pins  512  may include any suitable shapes configured to interface with the plurality of radial slots  500  of the receiving feature  400 . 
     Moreover, the plurality of radial pins  512  may be disposed at a first end  524  of the compliant housing  506 . The plurality of radial pins  512  may include the first radial pin  514  angularly offset  406  from the second radial pin  516  by substantially one hundred and eighty degrees such that the first radial pin  514  and the second radial pin  516  are disposed on opposing sides (e.g., a first radial side  526  and a second radial side  528 ) of the first end  524  of the compliant housing  506 . The sides of the compliant housing  506  may be connected via a flexible portion  530  of the compliant housing  506 . In the illustrated embodiment, the flexible portion  530  is disposed proximate a second end  532  of the compliant housing  506 . The flexible portion  530  is configured to deflect such that the first radial side  526  and the second radial side  528  move radially inwards towards each other. Applying a radial force to the first radial side  526  and the second radial side  528  of the compliant housing  506  may deflect the flexible portion  530 . In some embodiments, an operator may squeeze the compliant housing  506  by hand or with a tool to deflect the flexible portion  530 . The compliant housing  506  is accessible via the first axial end  314  of the gun body  134  such that the flexible portion  530  may be deflected while the charge tube  132  is disposed within the gun body  134 . Indeed, the compliant housing  506  and weighted feature  208  may be disposed at least partially between the first axial end  320  of the charge tube  132  and the first axial end  314  of the gun body  134  such that the compliant housing  506  is accessible via the first axial end  314  of the gun body  134 . 
     To adjust or re-position the weighted feature  208 , the axial force may be applied to portions of the first radial side  526  and the second radial side  528  of the compliant housing  506  extending out of the charge tube  132  to deflect the flexible portion  530  and retract the first radial pin  512  and the second radial pin  516  away from an inner surface  534  of the outer wall  502  of charge tube  132  in a radially inward direction  536 . Then, the compliant housing  506  may be rotated with respect to the charge tube  132  to a desired angular orientation. When the weighted feature  208  is disposed at the desired angular orientation  212  with respect to the charge tube  132 , the axial force may be released; thereby, releasing the flexible portion  530  to drive the radial pins  512  in the radially outward direction  504  and re-engage the radial pins  512  with the radial slots  500  corresponding to the desired angular orientation  212  of the weighted feature  208  with respect to the charge tube  132 . 
     The receiving feature  400  may include any number of corresponding radial slots  500  to receive the radial pins  512 . The receiving feature  400  may include additional radial slots  500  to increase the resolution for adjusting the angular orientation  212  of the weighted feature  208  with respect to the charge tube  132 . As set forth above, adjusting the angular orientation  212  of the weighted feature  208  is configured to adjust a center of gravity  138  of the charge tube  132  such that gravity will cause the charge tube  132  to rotate to a corresponding phasing angle (e.g., resting orientation). 
       FIG. 6  illustrates a perspective view of an adjustment arm  600  for adjusting the angular orientation of the weighted feature  208 , in accordance with some embodiments of the present disclosure. As set forth above, the perforating gun system  112  includes the charge tube  132  configured to house shaped charges  120 . Further, the charge tube  132  is disposed within the gun body  134  and is rotatably mounted to the gun body  134 . 
     In the illustrated embodiment, the perforating gun system  112  also includes an anchor arm  602  extending out from the first axial end  320  of the charge tube  132 . As illustrated, the anchor arm  602  may include a cylindrical shape, or any other suitable shape. A proximal end  604  of the anchor arm  602  may be integral with or fastened to (e.g., welded, brazed, threaded, etc.) the first axial end  320  of the charge tube  132 . The anchor arm  602  may extend out from a central portion  606  of the first axial end  320  of the charge tube  132 . In the illustrated embodiment, the anchor arm  602  extends out from the first axial end  320  along the rotational axis  140  of the charge tube  132 . However, the anchor arm  602  may extend out from any suitable portion of the first axial end  320  of the charge tube  132  that provides a sufficient radial gap  608  between the anchor arm  602  and the interior surface  302  of the gun body  134 . As set forth in detail below, the weighted feature  208  is configured to rotate around the anchor arm  602 . As such, the radial gap  608  may be larger than a radial width  610  of the weighted feature  208 , such that the weighted feature  208  has sufficient space to rotate around the anchor arm  602 . 
     Moreover, the anchor arm  602  may include a first interlocking feature  612  at a distal end  614  of the anchor arm  602 . In the illustrated embodiment, the distal end  614  of the anchor arm  602  extends past the first axial end  314  of the gun body  134 . Alternatively, the distal end  614  of the anchor arm  602  may be disposed between the first axial end  320  of the charge tube  132  and the first axial end  314  of the gun body  134 . The first interlocking feature  612  may include a spline (e.g., male spline or female spline) having ridges, teeth, and/or grooves. However, the first interlocking feature  612  may include any suitable interlocking feature for interfacing with a corresponding interlocking feature (e.g., a second interlocking feature  616 ) to lock rotational motion and permit axial motion between the corresponding interlocking features. 
     The perforating gun system  112  also includes the adjustment arm  600  that has the second interlocking feature  616  at a proximal end  618  of the adjustment arm  600 . The second interlocking feature  616  may include a spline (e.g., female spline or male spline) configured to interface/interlock with the first interlocking feature  612  at one of a plurality of angular orientations with respect to the charge tube  132 . Moreover, the adjustment arm  600  may include a handle  620  at a distal end  622  of the adjustment arm  600 . The handle  620  may be position outside of the gun body  134  proximate the first axial end  314  of the gun body  134 . However, in some embodiments, the handle  620  may be positioned within the gun body  134  between the first axial end  320  of the charge tube  132  and the first axial end  314  of the gun body  134 . Exerting an axial force on the handle  620  in the axial outward direction  414  (e.g., direction axially away from the charge tube  132 ) may disengage the second interlocking feature  616  from the first interlocking feature  612 , such that the adjustment arm  600  may rotate (e.g., adjust an angular orientation) with respect to the anchor arm  602  and the charge tube  132 . Exerting an axial force in the axial inward direction  416  (e.g., direction axially toward the charge tube  132 ) may re-engage the second interlocking feature  616  with the first interlocking feature  612  to lock rotational movement of the adjustment arm  600  with respect to the anchor arm  602  and the charge tube  132 . 
     Further, the perforating gun system  112  includes the weighted feature  208  rigidly secured to the adjustment arm  600 , such that an angular orientation  212  of the weighted feature  208  with respect to the charge tube  132  is based at least in part on the angular orientation of the adjustment arm  600  with respect to the anchor arm  602 . That is, the weighted feature  208  is configured to rotate about the anchor arm  602  in response to rotation of the adjustment arm  600  with respect to the anchor arm  602 . In some embodiments, the weighted feature  208  may be directly attached to the adjustment arm  600 . However, in the illustrated embodiment, the perforating gun system  112  includes a retainer  624  configured to rigidly secure the weighted feature  208  to the adjustment arm  600 . The retainer  624  includes a first end  626  that is rigidly coupled to the adjustment arm  600 . The first end  626  may be coupled to a portion of the adjustment arm  600  between the second interlocking feature  616  and the handle  620 . A second end  628  of the retainer  624  may be coupled to the weighted feature  208 . The retainer  624  may extend from the first end  626  to the second end  628  in the axial inward direction  416  (e.g., direction axially toward the first axial end of the charge tube  132 ) such that the second end  628  is axially aligned with at least a portion of the anchor arm  602 . Aligning the second end  628  with the anchor arm  602  may axially align the weighted feature  208  with the anchor arm  602  such that the weighted feature  208  rotates about the anchor arm  602 . Further, aligning the second end with the anchor arm  602  may position the weighted feature  208  within the gun body  134  between the first axial end  320  of the charge tube  132  and the first axial end  314  of the gun body  134 . 
     In some embodiments, the perforating gun system  112  further includes a spring feature  630  disposed between the weighted feature  208  and the first axial end  314  of the gun body  134 . The spring feature  630  may be a compression spring configured to bias the weighted feature  208  away from the first axial end  314  of the gun body  134  in the axial inward direction  416 . However, any suitable spring feature  630  may be used to bias the weighted feature  208  in the axial inward direction  416 . The spring feature  630  may be configured to provide the axial force in the direction axially toward the charge tube  132  (e.g., the axial inward direction  416 ) to re-engage the second interlocking feature  616  with the first interlocking feature  612  to lock rotational movement of the adjustment arm  600  with respect to the anchor arm  602  and the charge tube  132 . Further, the spring feature  630  may continually bias the adjustment arm  600 , via the weighted feature  208  and the retainer  624 , in the direction axially toward the charge tube  132  to keep the second interlocking feature  616  axially engaged with the first interlocking feature  612  during operation of the perforating gun system  112 . 
     As set forth above, the perforating gun system  112  may be configured to adjust the angular orientation  212  of the weighted feature  208  with respect to a charge tube  132  to adjust the center of gravity  138  of the charge tube  132 , which adjusts the resting orientation of the charge tube  132 ; thereby, adjusting the aimed direction of the shaped charges  120 . To adjust the angular orientation  212  of the weighted feature  208  in the illustrated embodiment, an operator may pull on the handle  620  to exert the axial force (i.e., greater than the biasing force from the spring feature  630 ) on the adjustment arm  600  in the axial outward direction  414  (e.g., direction axially away from the charge tube  132 ), which moves the adjustment arm  600  axially away from the anchor arm  602  and disengages the second interlocking feature  616  from the first interlocking feature  612 . While disengaged, the operator may rotate the adjustment arm  600 , via the handle  620 , to a desired angular orientation  212  for the weighted feature  208  with respect to the charge tube  132 . As set forth above, rotating the adjustment arm  600  rotates the weighted feature  208  about the anchor arm  602  due to the rigid connection of the weighted feature  208  to the adjustment arm  600  via the retainer  624 . Once the weighted feature  208  is disposed at the desired orientation, the operator may release the handle  620  such that the biasing force from the spring moves the adjustment arm  600  axially toward the charge tube  132  and re-engages the second interlocking feature  616  with the first interlocking feature  612 . 
     Accordingly, the present disclosure provides various systems configured to adjust an angular orientation  212  or radial position of a weighted feature  208  with respect to a charge tube  132  to adjust the center of gravity  138  of the charge tube  132 ; thereby, adjusting a resting orientation of the charge tube  132  to aim shaped charges  120  in the wellbore  114 . In addition to the systems described above, additional systems having ratchet devices, slide locks, collet devices, etc. may also be used to adjust the angular orientation or radial position of the weighted feature  208 . The systems may include any of the various features disclosed herein, including one or more of the following statements. 
     Statement 1. A perforating gun system, comprising: a gun body; a charge tube disposed within and rotatably mounted to the gun body, wherein the charge tube includes a receiving feature disposed at an axial end of the charge tube; at least one charge mounted within the charge tube, wherein the at least one charge is configured to perforate a sidewall of a wellbore upon detonation; and a weighted feature adjustably attached to the receiving feature of the charge tube in one of a plurality of angular positions, wherein adjusting the angular position of the weighted feature is configured to adjust a center of gravity of the charge tube such that gravity will cause the charge tube to rotate to a corresponding phasing angle. 
     Statement 2. The system of statement 1, wherein the weighted feature is disposed between the axial end of the charge tube and an axial end of the gun body. 
     Statement 3. The system of statement 1, further comprising an attachment feature mounted to the weighted feature and configured to interface with the receiving feature, wherein the weighted feature is adjustably attached to the receiving feature via the attachment feature. 
     Statement 4. The system of statement 3, the attachment feature is configured to adjust the angular position of the weighted feature with respect to the charge tube while the charge tube is disposed within and rotatably mounted to the gun body. 
     Statement 5. The system of statement 3, wherein the attachment feature is accessible and adjustable from an axial end of the gun body. 
     Statement 6. The system of statement 3, wherein the attachment feature comprises a plurality of pins mounted to an axial end of the weighted feature, and wherein the receiving feature comprises a plurality of corresponding slots disposed in an axial end of the charge tube, wherein each of the plurality of pins are configured to interface with each of the plurality of slots. 
     Statement 7. The system of statement 6, wherein the plurality of pins are configured to snap-fit to the plurality of corresponding slots. 
     Statement 8. The system of statement 3, wherein the attachment feature comprises a housing configured to mount to the receiving feature and house the weighted feature 
     Statement 9. The system of statement 1, wherein a center of mass of the weighted feature is radially offset from a central axis of the charge tube. 
     Statement 10. The system of statement 1, wherein the weighted feature comprises a semi-cylinder shape. 
     Statement 11. A perforating gun system, comprising: a gun body; a charge tube disposed within and rotatably mounted to the gun body, wherein the charge tube includes a plurality of receiving holes disposed at an axial end of the charge tube; at least one charge mounted within the charge tube, wherein the at least one charge is configured to perforate a sidewall of a wellbore upon detonation; a compliant housing having a plurality of pins disposed at a first end and a flexible portion disposed at a second end, wherein the flexible portion is configured to deflect to retract the plurality of pins with respect to the charge tube and to release to insert the plurality of pins into a set of the receiving holes corresponding to an angular orientation of the compliant housing with respect to the charge tube; and a weighted feature configured to adjust a center of gravity of the charge tube such that gravity will cause the charge tube to rotate to a corresponding phasing angle, wherein the weighted feature is secured to the compliant housing and configured to adjust the center of gravity of the charge tube based on the angular orientation of the compliant housing with respect to the charge tube. 
     Statement 12. The system of statement 11, wherein the plurality of pins extend from the compliant housing in a radially outward direction with respect to the central axis of the charge tube. 
     Statement 13. The system of statement 11, wherein the compliant housing is disposed between the axial end of the charge tube and an axial end of the gun body. 
     Statement 14. The system of statement 11, wherein the charge tube comprises a plurality of sets of receiving holes each corresponding to respective angular orientations of the compliant housing with respect to the charge tube. 
     Statement 15. The system of statement 11, and wherein the flexible portion is accessible via the axial end of the gun body such that the flexible portion may be deflected while the charge tube is disposed within the gun body to adjust the angular orientation of the compliant housing with respect to the charge tube. 
     Statement 16. A perforating gun system, comprising: a gun body; a charge tube disposed within and rotatably mounted to the gun body; at least one charge mounted within the charge tube, wherein the at least one charge is configured to perforate a sidewall of a wellbore upon detonation; an anchor arm extending out from a first axial end of the charge tube, wherein a distal end of the anchor arm comprises a first interlocking feature; an adjustment arm comprising a second interlocking feature configured to interlock with the first interlocking feature at one of a plurality of angular orientations, wherein the adjustment arm is accessible at an axial end of the gun body for disengagement and re-engagement of the adjustment arm with respect to the anchor arm to change the angular orientation of the adjustment arm with respect to the anchor arm; a weighted feature rigidly secured to the adjustment arm, wherein an orientation of the weighted feature with respect to the charge tube is based at least in part on the angular orientation of the adjustment arm with respect to the anchor arm, and wherein changing the orientation of the weighted feature with respect to the charge tube is configured to adjust a center of gravity of the charge tube such that gravity will cause the charge tube to rotate to a corresponding phasing angle. 
     Statement 17. The system of statement 16, wherein the anchor arm is disposed within the gun body between the axial end of the charge tube and an axial end of the gun body. 
     Statement 18. The system of statement 16, further comprising a retainer configured to rigidly secure the weighted feature to the adjustment arm, the retainer having a first end rigidly coupled to the adjustment arm and a second end coupled to the weighted feature, wherein the second end axially aligned with at least a portion of the anchor arm. 
     Statement 19. The system of statement 16, wherein the first interlocking feature comprises a spline interface having a plurality of ridges or teeth configured to mesh with corresponding grooves of the second interlocking feature. 
     Statement 20. The system of statement 16, further comprising a spring feature configured to bias the adjustment arm toward the anchor arm to secure the second interlocking feature against the first interlocking feature during operation of the perforating gun system. 
     For the sake of brevity, only certain ranges are explicitly disclosed herein. However, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as, ranges from any lower limit may be combined with any other lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited. Additionally, whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range are specifically disclosed. In particular, every range of values (of the form, “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a-b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values even if not explicitly recited. Thus, every point or individual value may serve as its own lower or upper limit combined with any other point or individual value or any other lower or upper limit, to recite a range not explicitly recited. 
     Therefore, the present embodiments are well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the present embodiments may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Although individual embodiments are discussed, all combinations of each embodiment are contemplated and covered by the disclosure. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. It is therefore evident that the particular illustrative embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the present disclosure.