Patent ID: 12252964

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

DETAILED DESCRIPTION

The perforation tools described herein use frames for shaped charges that accommodate large charges that extend across the diameter of the tool, which is generally tubular or cylindrical, and that provide ballistic and electrical transfer integrated into the frame. Some embodiments herein are also indexable so that individual frames can point the shaped charges in different directions that can be selected, while maintaining ballistic transfer and electrical connectivity.

FIG.1Ais a cross-sectional view of a perforation tool100according to one embodiment. The perforation tool100uses one or more frames102to hold shaped charges in a container104. The tool100is deployed in a well drilled into a formation. When activated, the shaped charges produce a jet of reaction products that pierce the container104and penetrate the formation to facilitate recovery of resources from the formation. The container104has an outer wall105with a reduced thickness zone107at a location adjacent to a frame cavity109of the container104. The frame cavity109is defined by a ledge111extending inward from the outer wall105. The ledge111supports the frame102at the desired location adjacent to the reduced thickness zone107, and may extend entirely around the circumference of the container104, or partway, or piecewise around the circumference of the container104. The reduced thickness zone107may form a band around the container104. Thus, the reduced thickness zone107may be a continuous zone that circumscribes the outer wall105of the container104. In some cases, the ledge111may be replaced by a short stub that extends inward from the outer wall105. The reduced thickness zone107may alternately be a zone that proceeds partway around the container104. The reduced thickness zone107allows for penetration of reaction products through the container104. Using a band around the circumference of the container104allows the frame102to be positioned in any desired rotational orientation to provide a jet in the desired direction.

Typically, frames for shaped charges have one or more recesses to hold the shaped charges. The recesses generally have a cone or bell shape, or another shape generally tapering from a wide edge that accommodates the wide end of a shaped charge, to a narrow apex where the corresponding apex of the shaped charge fits. Shaped charge frames have generally cylindrical shapes with a central axis that aligns with, or coincides with, a central axis of the container when installed. The recesses also have central axes that are typically perpendicular to the central axis of the frame. The recesses typically have a wide end and a narrow end that defines an apex of the recess. The shape of the recess is usually defined to follow the shape of the charge to be installed in the recess.

In some cases, the wide end and narrow end of the recess are on the same side of the central axis of the frame, with the apex near the central axis so that communication of various sorts can be deployed along the central axis of the frame. In this way, the apex of the shaped charge can be positioned near the central axis of the frame so the shaped charge can be activated using communication along the central axis of the frame. In such cases, the apex of the recess is between the central axis of the frame and the wide end of the recess. This typically enables positioning multiple recesses around the axis of the charge frame, potentially at the same axial coordinate, with one communication path for all recesses extending along the central axis. Such construction limits the size of the charge that can be installed in the perforation tool.

Other tools have large shaped charges where the central axis of the frame is between the narrow and wide ends of the recess, such that the bulk of the shaped charge extends substantially across the tool from one side to the other. Such shaped charges allow for larger, more penetrating, discharges using a relatively small tool, but the central communication conduit feature described above is not available in such frames. The tools described herein use frames for large shaped charges that have integrated electrical and ballistic communication in a modular construction that is, in many cases, freely indexable to any direction.

The tool100has a generally cylindrical shape, and defines a longitudinal axis106. In the perforation tool100, the frames102have a generally cylindrical shape, with a central axis that coincides with the longitudinal axis106when the frame is deployed in the tool100. Each frame102has one recess108for holding a shaped charge. When the frame102is deployed in the tool100, the longitudinal axis106is located between a narrow end110of the recess108and a wide end112of the recess108. The recesses108in the frames102ofFIG.1Acan thus hold larger shaped charges than frames with recesses that do not extend across the longitudinal axis106.

The frame102is generally made of plastic, or another material having a certain flexibility. The frame102can be molded or 3-d printed, for example, from a tough flexible plastic like polypropylene or polyurethane.

The recess108is configured to hold a shaped charge (not shown) that has a wide end and a narrow end. The shaped charge fits in the recess108with the wide end of the shaped charge at the wide end112of the recess108and the narrow end of the shaped charge at the narrow end110of the recess108. The wide end112of the recess108has a rim156that generally secures the shaped charge in the recess108. The wide end112of the recess108also has a tab158that flexes to capture the wide end of the shaped charge, thus securing the shaped charge into the recess108. The rim156of the recess108may have a finger notch157to facilitate insertion and removal of shaped charges. The narrow end110of the recess108has an opening119for electrical and/or ballistic communication at the apex of the shaped charge.

The perforation tool100has one or more energy modules114with a bulkhead member116at either end of the energy module114. Where multiple energy modules are used, a bulkhead member116separates one energy module114from a neighboring energy module114. The bulkhead member116is a hard, solid mass, usually steel, that fits into an end of the container104, thus sealing the energy module114inside the container104. The bulkhead members116minimize transmission of energy from an energy module114beyond the bulkhead member116. The bulkhead member116may be connected to the container104using a threaded connection or using a non-threaded connection. Here, a non-threaded connection is shown.

The energy module114comprises one or more charge frames102, as described above, along with an initiator module118between the charge frame102and the bulkhead member116. The initiator module118contains circuitry to produce an electrical impulse that activates the shaped charge in the recess108. The circuitry is typically housed in a circuit board120oriented transverse to the central axis106of the tool100. The electrical impulse is used to activate a detonator122housed by the initiator module118and electrically coupled to the circuit board120.

The initiator module118, in this case, has two locations for housing the detonator122. As shown inFIG.1A, a first detonator housing124is located in a peripheral area of the initiator module118. The detonator122is shown installed in the first detonator housing124inFIG.1A. An opening126of the detonator housing124is aligned with an opening128of the frame102. The opening126provides fluid communication between the detonator housing124and a capsule housing127of the frame102. An activation capsule130is disposed in the opening128of the frame102. Activation of the detonator122creates an energy discharge that travels through the opening126of the detonator housing124into the opening128of the frame102and activates the capsule130. Activation of the capsule130, in turn, creates an energy discharge that travels through the opening119at the narrow end110of the recess108and activates the shaped charge disposed in the recess108.

The frame102provides electrical connectivity from the initiator module118to other modules that may be installed in the tool100. The frame102has an electrical conductor132that extends from a first end134of the frame102to a second end136of the frame102opposite from the first end134.FIG.1Bis a back view of the frame102ofFIG.1A.FIG.1Cshows the electrical conductor132. The electrical conductor132is a band or wire with a first end138, which is located at the first end134of the frame102, and a second end140, which is located at the second end136of the frame102. The electrical conductor132is angled in a square “U” shape so that the ends138and140can be located near the center of their respective sides of the frame102while a central portion141of the electrical conductor132, between the first and second ends138and140, is located near a side of the frame102and forms an angle with the first and second sides138and140. The electrical conductor132is disposed with the central portion141in a passage142in a side of the frame102, so the electrical conductor132is detachably integrated with the frame102. Specifically, the electrical conductor132can be detached from the frame102by sliding the electrical conductor132out of the passage142. If necessary, one or both of the first and second ends138and140can be straightened with respect to the central portion141to facilitate insertion or removal. For example, prior to insertion, one of the first or the second end138/140can be substantially parallel with the central portion141for insertion into the passage142. After insertion into the passage142, the “unbent” end can be bent into proximity with the central portion of the side of the frame102. Likewise, to remove the electrical conductor132, one end can be “unbent” to allow easy removal.

The first end138of the electrical conductor132is located near a center of the first end134, where the central axis106intersects the first end134, and the second end140is located near a center of the second end136, where the central axis106intersects the second end136. The electrical conductor132extends around a periphery of the frame102from the first end134to the second end136thereof. The electrical conductor132is a flat-spring-type contact with the first and second ends138and140extending away from the respective first and second ends134and136of the frame102at an angle. When the frame102is disposed in the container104, the ends138and140of the electrical conductor132contact other electrical members of the tool100and flex to provide a contact force for secure electrical contact. In this way, electrical continuity across the frame102is maintained. The ends138and142are shown with connectivity enhancing features143, in this case fingers that make the ends138and142comblike. Any connectivity enhancing features can be used, including different shapes and compositions. For example, a coating, or small spot, of highly conductive material, such as gold, can be applied to the electrical conductor132to enhance connectivity. Alternately, a brush-like or wool-like conductive material can be used at the ends138and140to enhance electrical connectivity.

The electrical conductor132provides electrical continuity from a central area of the first end134to a central area of the second end136passing along a periphery of the frame102. The flat-spring ends of the electrical conductor132provide resilient, deformable electrical contacts for securing electrical continuity at both ends of the frame. In other embodiments, resilient electrical contacts may be located at the central areas of the first end134and the second end136, and the resilient electrical contacts can be electrically coupled to an electrical conductor disposed within the frame in a non-removable manner. The resilient electrical contacts may be any kind of spring, such as a flat spring or coil spring, and may be electrically coupled to the electrical conductor at any location between the central area of the frame ends and a peripheral area of the frame ends. Different types of resilient electrical contacts can be used at the ends of the frame, if desired.

Referring again toFIG.1A, the electrical conductor132may be electrically coupled to the initiator module118by contact with an electrical member144of the initiator module118disposed along the central axis106. The electrical member144extends from a contact surface at a first end146of the initiator module118to an electrical assembly148at a second end150of the initiator module118. The electrical member144contacts the electrical conductor132of the frame102at the first end of the initiator module118to provide electrical feedthrough to the frame102.

The frame102is stackable with other frames. Specifically, more than one of the frames102can be included in a perforation tool.FIG.2is an exploded view of an energy module200useable in a perforation tool, according to one embodiment. The energy module200features the initiation module118with two shaped charge frames102, a first shaped charge frame102A and a second shaped charge frame102B. The initiation module118, first shaped charge frame102A, and second shaped charge frame102B have alignment features that preserve alignment of the ballistic communication pathway that activates the shaped charges in the frames102A and B. Each of the frames102A and B has a post208for mating with an opening210to maintain alignment. The initiator module118also has one of the openings210to align with the first shaped charge204.

The alignment features maintain alignment of ballistic communication pathways. Specifically, the first and second charge frames102A and102B each have the capsule housing127and the opening128. Together with the first detonator housing124, the openings128and capsule housings127provide a fluid communication pathway from the first detonator housing124to the narrow ends of the recesses108of the first and second charge frames102A and B to activate charges in the frames102A and B. The alignment features can take any form or configuration, such as pumps, posts, tabs, and the like, with the openings taking any commensurate shape as well. It should be noted that any number of charge frames102can be used in this way in the energy module200.

Here, the posts208extend in a direction parallel to the central axis106. Each post208is spaced apart from the longitudinal axis106by an arbitrary distance. In this case, each post208and each opening210, is located near an outer edge of the frames204and206, and the initiator module202. Thus, all the components of the energy module200can be maintained in alignment. If a particular alignment within the container104(FIG.1) is desired, a notch212in the edge of the initiator module202can be engaged with a ridge (not shown) that can be provided along an interior wall of the container104to align all the members of the energy module.

FIG.3is a cross-sectional view of a perforation tool300according to another embodiment. The initiator module118has a second detonator housing302located along the central axis of the initiator module118, which coincides with the central axis106of the tool300. The second detonator housing302is a tubular member that can hold a detonator such as the detonator122. Here the second detonator housing302is a “half-pipe” in which the detonator122rests, with a clip304that holds the detonator122in the half-pipe. Electrical leads310from the detonator122may be routed to the circuit board120in any convenient way. In this case, the leads are routed through a peripheral opening307into the electrical assembly148.

In the perforation tool300, the detonator122is not physically aligned with the capsule130, but is centrally located along the central axis106of the tool300. Ballistic transfer from the detonator122to the capsule130can be achieved by routing a combustible conduit306between the detonator122and the capsule130through a gap308between the frame102and the initiator module118. The gap308is maintained by a spacing force provided by the electrical conductor132. As noted above, the ends of the electrical conductor132are configured as flat springs to provide the spacing force to maintain the gap308. The combustible conduit306may be a detonation cord or other combustible conduit, and is routed from a location near the detonator and the end of the electrical conductor132to a location near the capsule130in the capsule housing127. Upon activation of the detonator122, energy transfers to the combustible conduit306, and along the combustible conduit306to the capsule130, which in turn activates the shaped charge in the frame102. In such embodiments, the frame102can be oriented in any desired direction to provide a perforating jet in the desired direction, while maintaining electrical and ballistic continuity. To accomplish such rotatability, the alignment features mentioned above in connection withFIG.2can be eliminated, or in other embodiments multiple openings210can be provided in the initiator module118to engage with the post208in multiple indexed orientations.

FIG.4is a cross-sectional view of a perforation tool400according to another embodiment. The perforation tool400uses a plurality of shaped charge frames402. The shaped charge frames402are slightly different from the frames102in that each frame has the opening128that provides ballistic transfer to the capsules130, but each frame402has an outlet404of the conduit127that provides a fluid pathway for the capsule130of one frame402to transfer energy to the capsule of an adjacent frame402through the conduits127of the frames. Any number of the frames402can be used in this way to activate an arbitrary number of shaped charges. Electrical continuity is provided across all the frames402by electrical contact of the conductors132of the adjacent frames402. In this case, alignment of the conduits127is maintained using alignment features such as those described above in connection withFIG.2. It should be noted that, although the detonator122is shown inFIG.4in the central location, using the second detonator housing302and the combustible conduit306, the detonator122could be located in the first detonator housing124. It should also be noted that, where multiple frames are used in an energy module, as shown inFIG.4, each frame will have a corresponding reduced thickness zone107in the outer wall105of the container104.

FIG.5is a cross-sectional view of a perforation tool500according to another embodiment. The tool500uses an energy module502with different features from those of the other perforation tools described above. The energy module502has an initiator module504with a hollow pin connector506at a first end508of the initiator module504. The circuit board120is located at a second end510of the initiator module504, as in other embodiments herein.

The energy module502uses a shaped charge frame512that has a pocket electrical connector514at a first end513of the frame512. The pocket connector514features a recess516with a plurality of bearings518disposed therein. The bearings518, in this case, are cylindrical roller bearings. The pocket connector514is coupled to the electrical conductor132(FIG.1C), not shown inFIG.5. To provide electrical continuity across the frame512, the pin connector506of the initiator module504engages with the pocket connector514by inserting into the recess516. Here, the pin connector506is axially rigid with no axial movement capability such as spring-loading or extension/retraction. The bearings518make contact with the pin connector506, providing electrical continuity between the initiator module504and the frame512. In some embodiments, instead of a plurality of roller bearings, a single band bearing, configured as a hollow cylinder, can be used as a bearing in the recess516. In other embodiments, the pin connector506and pocket connector514, which may be a box connector, make direct electrical contact without the use of a bearing, and the pin connector506is able to rotate within the pocket connector514while maintaining electrical connection.

Ballistic continuity is provided by a tunnel540formed through the frame512. The frame512has an outer wall520that contains the shaped charge within a recess522. The recess522has a wide end524and a narrow end526. The outer wall520has a thin portion528at the wide end524and a thick portion530at the narrow end526. The thickness of the thick portion530increases from a middle location of the outer wall520, about midway between the narrow end526and the wide end524, toward the narrow end526. The tunnel540extends from the pocket connector514to the capsule housing127adjacent to the narrow end526of the recess522. The tunnel540provides fluid communication between the second detonator housing302and the capsule housing127, and is shaped and positioned to support ballistic continuity from the detonator to the capsule130. The pin connector506has a passage550formed therein, along a longitudinal axis thereof. The passage550is in fluid communication with the second detonator housing302. The pocket connector514has an opening552that provides fluid communication between the tunnel540and the passage550. The passage550, opening552, and tunnel540thus provide a continuous fluid pathway from the second detonator housing302to the capsule housing127. Activation of the detonator122in the second detonator housing302projects ballistic energy along the passage550, through the opening552, and along the tunnel540to the capsule housing127, activating the capsule130and the shaped charge in the recess522.

The frame512has a pin connector554at a second end553of the frame512opposite from the first end513. The pin connector554is substantially similar to the pin connector506, and is suitable for engaging with a pocket connector of another component. Here, a bulkhead member556is shown connected to the frame512by a pocket connector558substantially similar to the pocket connector514of the frame512. The pin connector554also has a longitudinal passage555for fluid continuity, should fluid continuity at the pin connector554be desired.

The frame512has an optional second tunnel560that extends from the capsule housing127to the pin connector554. Where the frame512has a second tunnel560, the tunnel540is a first tunnel, and the first and second tunnels540and560provide a fluid pathway through the frame512from the pocket connector506, past the narrow end526of the recess522through the capsule housing127, to the pin connector554, a continuous fluid pathway through the frame512from the first end528to the second end553. The optional second tunnel560can be used to provide ballistic continuity across the frame512, so that activation of the capsule130can provide ballistic energy transfer from the frame512to another component, such as another frame512, connected to the frame512. Because the pin and pocket connectors506,514,554, and558are rotatably engaged using roller bearings, the frame512is free to rotate to any angle while maintaining electrical continuity. The passage550, opening552, and tunnel540provide fluid continuity at any rotation angle of the frame512, and the second tunnel560and passage555provide outlet fluid continuity from the capsule housing127to the pin connector554at any rotation angle of the frame512. In this way, the frame512has integral electrical and ballistic continuity, and is rotatable to any angle to direct discharge from the shaped charge in any desired direction.

As noted above, the frame512uses an electrical conductor like the conductor132ofFIG.1Cdetachably disposed in a passage (FIG.1B) through the frame512along a side thereof. The passage proceeds around the recess522and has openings at the first end528and the second end553of the frame512. The electrical conductor provide electrical continuity across the frame from the pocket connector514to the pin connector554. The tunnel540, capsule housing127, and second tunnel560form a second passage through the frame512from the first end528to the second end553for ballistic continuity. The second passage runs from a central area of the first end528, adjacent to the narrow end of the recess522, to a central area of the second end553. The passage550of the pin contact506of the initiator module504, together with the opening552in the pocket connector514of the frame512, provide fluid communication between the second passage through the frame and the second detonator housing302of the initiator module504. In this way, electrical and ballistic continuity are integral to the frame512. It should be noted that ballistic conduits can be used in the tunnels540and560, or combustible material may be directly inserted into the tunnels540and560for ballistic transfer.

FIG.6is a cross-sectional view of a perforation tool600according to another embodiment. The perforation tool ofFIG.6uses an energy module602that includes the initiator module504and two of the shaped charge frames512connected together to illustrate the electrical and ballistic continuity characteristics of the initiator module504and the frame512. Here, a first frame512A is connected to the initiator module504by a pin-pocket electrical connector, with the pin connector506of the initiator module connected to the pocket connector514A of the first frame512A, the pin connector554A of the first frame512A connected to the pocket connector514B of the second frame512B, and the pin connector554B of the second frame connected to the pocket connector558of the bulkhead member556. The tunnels540A and560A of the first frame512A provide fluid communication from the second detonator housing302of the initiator module504to the longitudinal passage555A of the first frame512A, which in turn fluidly communicates with the tunnels540B and560B of the second frame512B. The continuous fluid pathway from the detonator122in the initiator module504to the capsules130A and130B of the frames512A and512B activates the shaped charges in the frames512A and512B upon activation of the detonator122. The electrical and fluid continuity integral to the frames512A and512B, along with the rotatable nature of the pin pocket connectors, provide the capability to rotate the frames512A and512B to any angle, which may be the same or different for the two frames512A and512B, while maintaining electrical and ballistic continuity.

FIGS.7A and7Bshow two different uses of a shaped charge frame700according to another embodiment.FIG.7Ashows the shaped charge frame700from a first end712thereof andFIG.7Bshows the shaped charge frame700from a second end714thereof. The shaped charge frame700is similar to the shaped charge frame512ofFIG.5, with a first rotatable electrical connector702at the first end712and a second rotatable electrical connector704, which is connectable with the first rotatable electrical connector702, at the second end714. The rotatable electrical connectors702and704may be any type of rotatable connector, of which the pin-pocket connectors ofFIGS.5and6are examples. The rotatable electrical connectors702and704provide free rotation of the frame700when installed in a downhole tool.

The frame700has a plurality of openings706formed in the first end712thereof. The first end712has a substantially solid first disk708, at the center of which the first rotatable connector702is located. The openings706are formed in a peripheral area of the first disk708. The second end714also has a substantially solid second disk710, at the center of which the second rotatable connector704is located. The second disk710also has a plurality of openings716. The openings706and716may be used as alignment features when two of the frames700are disposed in a downhole tool. Because the frame700can freely rotate while maintaining electrical and fluid continuity, one frame700can be installed in a downhole tool with a first angular orientation and a second frame700can be installed in the same downhole tool with a second angular orientation different from the first angular orientation. To avoid unwanted rotation of the frames700, a pin can be installed that extends from one of the openings716of a first frame700of the downhole tool to one of the openings706of a second frame700of the downhole tool to maintain angular orientation of the frames700. A similar opening can be provided at an end of the initiator module504, if desired, to lock rotation of the frames700with respect to the initiator module504.

The openings706and716can also be used to provide self-orienting for the frame700. A weight718can be installed in one of the openings706or the openings716. Where the frame700is in a substantially non-vertical orientation, the weight718can provide imbalance in the mass distribution of the frame700that results in gravitational self-orientation of the frame700. The weight718causes the frame700to rotate about the rotatable connectors702and704such that the weight718moves to a lowest position, orienting the frame700with shaped charged therein at a desired angular orientation to provide discharge in a desired direction. As shown inFIG.7, the plurality of openings706and716can be used to provide self-orientation of the frame700in many directions.

FIGS.8A and8Billustrate how weights718can be used in the frames700to provide fractionally indexed angular self-orientation of the frames700. Here, two weights718are used to provide a fractional angular orientation that is between the angular orientations provided by use of single weights718. Here, two weights provide a distributed mass imbalance that moves to a lowest gravitational energy position. With10openings706and716at either end of the frame700, up to 20 weights718can be inserted into the openings to provide a very large number of unique orientations for the frames700to assume in a non-axial gravitational field. Of course, any number of openings can be provided in the frame700. For example, the frame700might have just one opening, or just two openings, or any integer number of openings. The openings can be sized to provide space for the desired number of openings. The weights718are made of a dense material such as a dense metal that can substantially alter the mass distribution of the frame700.

FIG.9illustrates the use of the self-orienting frames700in a downhole tool in the presence of a non-axial gravitational field. Here a first frame700A has a first weight718A in one of the openings706A in the first end712A of the first frame700A, and a second frame700B has a second weight7186in one of the openings706B in the first end712B of the second frame700B. The two weights718A and718B are disposed in different openings such that the two frames700A and700B have different mass distributions. Upon encountering a non-axial gravitational field, the two frames700A and700B rotate to lowest gravitational energy positions, with the weights718A and718B at lowest positions. This results in the frames self-orienting to different angular orientations, as shown by arrows902. Here, two frames700are shown, but any number of frames can be used in one energy module of a downhole tool to provide directional discharges in selected directions using self-orienting shaped charge frames.

FIG.10Ais a cross-sectional view of a perforation apparatus1000according to one embodiment. The perforation apparatus1000has a loading tube1002for holding explosive charges, an initiator module1004that initiates discharge of the explosive charges, and a bulkhead member1006that separates the explosive charges of the loading tube1002from sensitive electronics in the initiator module1004. The loading tube1002has a plurality of recesses1008for receiving explosive charges and orienting the charges in a phased orientation. Thus, in this case, the perforation apparatus1000activates a plurality of shaped charges using one initiator module1004and one bulkhead member1006. Here, the recesses1008are arranged in a spiral arrangement pointing in various directions from the central axis of the perforation apparatus1000to provide phased discharge. In this case, each recess1008points in a different direction than the other recesses1008, but some of the recesses1008could point in the same direction. Here, each recess1008points in a direction, and the direction of each recess1008forms a constant angle with the direction of neighboring recesses1008. That is to say, in this case, the direction of each recess i and the direction of the neighboring recess i+1 forms an angle that is constant for all recesses i.

FIG.10Bis a detail view of the bulkhead member1006ofFIG.10A. The bulkhead member1006has a generally cylindrical body1010, or a shape conducive to housing in a desired casing. The body1010of the bulkhead member1006may be solid, or may be mostly hollow, as in this case. Here, the body1010has an outer shell1011with a central plate1012transverse to a longitudinal axis of the body1010. The outer surface of the outer shell1011has conveniently placed grooves1013to receive seal members1015for sealing against an outer casing. The central plate1012provides structural support for components of the bulkhead member1006, while the hollow configuration of the body1010reduces weight. The central plate1012defines a first cavity1014, generally facing a first end1016of the body1010, and a second cavity1018, generally facing a second end1020of the body1010. The central plate1012separates the first cavity1014from the second cavity1018such that when the bulkhead member1006is assembled into a perforating tool, the first cavity1014faces a first tool member and the second cavity1018faces a second tool member. In the case ofFIG.10A, the first cavity1014faces the initiator module1004and the second cavity1018faces the loading tube1002.

The central plate1012supports a feedthrough1022, which provides a conduit for electrical conductivity from the first end1016to the second end1020of the bulkhead member1006. The feedthrough1022has a central bore1025, oriented along the longitudinal axis of the bulkhead member1006, that extends through the central plate1012from the first cavity1014to the second cavity1018. A first protrusion1024extends from a first side1026of the central plate1012into the first cavity1014, and a second protrusion1028extends from a second side1030of the central plate1012into the second cavity1018. The central bore1025extends along and within the first protrusion1024, through the central plate1012, and along and within the second protrusion1028to provide a pathway through the central plate1012from the first cavity1014to the second cavity1018.

The bulkhead member1006, here, is non-symmetric. The bulkhead member1006has a generally cylindrical shape with a central longitudinal axis1001that generally resembles a cylindrical axis. In one aspect, a center of mass of the bulkhead member1006is closer to the first end1016of the bulkhead member1006than to the second end1020of the bulkhead member1006. In another aspect, the bulkhead member1006has no plane of symmetry that intersects the central longitudinal axis1001. For example, the bulkhead member1006has no transverse plane of symmetry.

An electrical conductor1032is disposed in the central bore1025to provide electrical conductivity from the first end1016to the second end1020of the bulkhead member1006. The electrical conductor1032has a pin connection1034at a first end thereof and a box connection1036at a second end thereof opposite from the first end. When the electrical conductor1032is installed in the bulkhead member1006, the pin connection1034is disposed in the first protrusion1024and the box connection1036extends beyond the second protrusion1028. The electrical conductor1032is a rod-like member that extends from the pin connection1034at the first end to the box connection1036at the other end The box connection1036is a hollow cylindrical member with diameter larger than a diameter of the rest of the electrical conductor1032so that the box connection1036can receive an electrical connector of another tool into the hollow cylindrical box connection1036. In some embodiments, the box connection1036may be described as a “female” electrical connection, while the pin connection1034may be described as a “male” electrical connection. Here, the pin connection1034is axially rigid with no axial movement capability such as spring-loading or extension/retraction.

An electrical insulator1038is disposed within the central bore1025around the electrical conductor1032to prevent electrical connection between the electrical conductor1032and the body1010. The body1010is typically made of steel to provide pressure insulation between the loading tube1002, where the charges discharge, and the initiator module1004, where sensitive electronics are located to control operation of the tool. In some embodiments, where the body1010can be made from a dense, hard, non-conducive material, such as hard plastic, the electrical insulator1038might not be needed. The electrical insulator1038has a seal portion1040that inserts into a throat1042of the central bore that extends into the central plate1025. The seal portion1040has a groove1044that accommodates a seal member1046to provide a secure fit for the electrical conductor1032within the central bore1025. The electrical insulator1038extends from the seal portion1040to an entry portion1047that houses the box connection1036of the electrical conductor1032. The entry portion1047has a shape similar to the shape of the box connection1036, in this case a hollow cylindrical shape with an inner diameter approximately equal to an outer diameter of the box connection1036so that an inner surface of the electrical insulator1038contacts an outer surface of the box connection1036. The seal members1015and1046provide pressure seal against the hydrostatic pressure of the well environment, as well as pressure seal between adjacent tools.

The electrical conductor1032extends beyond the seal portion1040of the electrical insulator1038through the central plate1012, where the central bore1025defines an annular gap1050around the electrical conductor1038. A wall1053extends radially inward from an interior wall of the central bore1025toward the electrical conductor1032to define the gap1050. The electrical conductor1032further extends into the first protrusion1024to the pin connection1034. The electrical insulator1038thus extends from the box connection1038partway along the length of the electrical conductor1032to the annular gap1050. Each of the electrical insulator1038and the electrical conductor1032extends beyond the second protrusion into the second cavity1018and beyond the second end of the body1010to provide an accessible electrical connection to accommodate another tool.

InFIG.10B, the loading tube1002has a connector1052that can be inserted into the box connection1038of the bulkhead member1006. The connector1052has a metal pin1054and a metal stub1056over the metal pin1054, with an overmolded plastic body1058that locates the metal pin1054and metal stub1056at the end of the loading tube1002. Inserting the metal stub1056into the box connection1038of the bulkhead member1006establishes electrical connection between the bulkhead member1006and the loading tube1002.

A plug connector1060is disposed within the end of the first protrusion1024around the pin connection1036of the electrical conductor1032. The plug connector1060provides electrical connection to a wire contact1062of the initiator module1004. The plug connector1060can be an RCA connector, or another convenient type of connector. The wire contact1062connecting with the plug connector1060electrically connects the bulkhead member1006with the initiator module1004. In this way, electrical connection is established from the initiator module1004, through the bulkhead member1006, to the loading tube1002.

Returning toFIG.10A, electrical conductivity is established along the loading tube1002by connecting a wire (not shown) to the connector1052. The connector1052is a first connector of the loading tube1002, located at a first end1066thereof. The loading tube1002has a second connector1064located at a second end1068thereof, opposite from the first end. The wire is connected from the first connector1052to the second connector1064, traversing the length of the loading tube1002according to any convenient path.

A second loading tube1002is shown inFIG.10Ato illustrate connection of the loading tube1002, at the second end1068thereof, to the initiator module1004. A band connector1070is disposed in a central recess1072of the second connector1064. The band connector1070makes electrical contact with a housing1074of the initiator module1004. The housing provides electrical connection to the wire contact1062(FIG.10B) of the initiator module1004and a circuit board1076disposed at an end of the initiator module1004that connects to the bulkhead member1006, and oriented generally transverse to the longitudinal axis of the perforation tool1000. Alternately, in embodiments where the housing1074is made of a non-conductive material, an electrical contact can be provided for connecting with the band connector1070, and an electrical conductor can be routed through the housing1074for connection with the wire contact1062and the circuit board1076.

The loading tube1002, initiator module1004, and bulkhead member1006all fit within a housing1007. InFIG.10A, the housings1007of two adjacent and connected perforation assemblies are shown connected by a threaded connection1009, each end of each housing1007having threads. Each housing1007has a first end1003and a second end1005, opposite from the first end1003, with each end1003and1005having threads. Here, the bulkhead member1006is shown connecting with each end1003and1005of a housing1007. Referring again toFIG.10B, the first end1016of the bulkhead member1006engages with a first end1003of a first housing1007while the second end1020of the bulkhead member1006engages with a second end1005of a second housing1007, which is coupled to the first housing1007. In this case, the bulkhead member1006connects with each housing using a friction fit, with a non-threaded connection, but a threaded connection can be used to connect the bulkhead member1006with either the first end1003or the second end1005of a housing1007.

In operation a detonator1080(FIG.10A) is disposed in a recess of the initiator module1004. The detonator1080extends into the central recess1072of the second connector1064of the loading tube1002. A booster (not shown) is also disposed in the central recess1072of the second connector1064. Detonation cord is connected to the booster and routed along the loading tube1002to the charges held therein. An electrical signal received at the circuit board1076, causes the circuit board to send an electrical signal that activates the detonator1080, which in turn discharges the booster. The ballistic discharge of the booster is transmitted by the detonation cord to the charges held in the loading tube1002.

FIG.11Ais a perspective side view of an energy module1100according to another embodiment. The energy module1100is a modular assembly, with a plurality of shaped charge frames1102that connect together. Here, each shaped charge frame1102holds one shaped charge, similar to the shaped charge frames102ofFIG.2. Each shaped charge frame1102has at least two prongs1104at a first end1106of the frame1102, and a matching number of openings1108at a second end1110of the frame1102to receive the prongs1104of another frame1102. In this way, multiple frames1102can be connected together to form a shaped charge frame assembly1100. Like the posts208ofFIG.2, the prongs1104and openings1108align the frames1102and maintain alignment of the frames1102. The frames1102are rotatable using the rotation methods and apparatus described herein.

It should be noted that the shaped charge frames1102could hold more than one shaped charge.FIG.11Bis a perspective side view of a modular shaped charge frame1152, like the shaped charge frame1102, that holds four shaped charges. Here, four of the frames1102are yoked together to form the modular frame1152. The frame1152uses detonation cord for ballistic continuity from the initiator module to the four shaped charges, and can use the various electrical continuity methods described elsewhere herein. Each of the frames1102has a peripheral conduit1154that runs adjacent to the narrow end of each shaped charge receptacle in each frame1102. The conduits1154form a continuous passage along the periphery of the modular frame1152to accommodate the detonation cord, or other ballistic transfer mechanism. The frame1152can also engage or connect with the initiator modules and bulkhead members described herein, can rotate using the rotation methods and apparatus described herein, and can self-orient using weight members to adjust center of gravity, as described herein.

At least one of the shaped charge frames1102has openings1112at the first end1106, the second end1108, or both to receive weight members1114to make the energy module1100self-orienting, as described elsewhere herein. Ballistic continuity is accomplished in the shaped charge frames1102using methods and apparatus described herein. Each of the frames1102has an external conduit1116that extends along an external radius1118of the frame1102in an axial direction thereof. The external conduits1116of connected frames1102form a single external conduit1120along the external radius1118of the frames1102from a first end1122of the energy module1100to a second end1124of the energy module1100, opposite from the first end.

An electrical conductor1126, similar to the electrical conductor132ofFIG.1C, can be disposed through the external conduit1120from the first end1122to the second end1124. The electrical conductor1126, so disposed, provides electrical continuity from the first end1122to the second end1124of the energy module1100. Any number of the frames1102can be thus chained together to house shaped charges in an energy module between an initiator module and a bulkhead member according to the manner ofFIG.11A.

While the foregoing is directed to embodiments of the present invention, other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.