Detonator assembly for wellbore perforator

The disclosed embodiments include a perforating gun assembly. The perforating gun assembly includes a housing and at least one perforating charge disposed within the housing. Additionally, the perforating gun assembly includes a detonating cord disposed within the housing and ballistically coupled to the at least one perforating charge. Also included in the perforating gun assembly is a detonator assembly disposed in line or adjacent to the detonating cord. The detonator assembly includes a detonator, a ballistic interrupt, an actuator to remove the ballistic interrupt from a line of fire of the detonator, and a detonator control board to control the actuator and firing of the detonator.

BACKGROUND

The present disclosure relates generally to downhole perforating guns used within a well, and more specifically to a detonator assembly used to detonate the downhole perforating guns.

When transporting downhole perforating guns between a gun loading facility and a well site for final use, certain precautions are taken. For example, the downhole perforating guns may include removable ballistic interrupts between detonators and detonating cords of the downhole perforating guns. The removable ballistic interrupt is manually removed prior to deploying the downhole perforating gun within a well. This removal of the ballistic interrupt leads to additional operational steps and manual handling of an armed perforating gun.

DETAILED DESCRIPTION

As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprise” and/or “comprising,” when used in this specification and/or the claims, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. In addition, the steps and components described in the above embodiments and figures are merely illustrative and do not imply that any particular step or component is a requirement of a claimed embodiment.

Unless otherwise specified, any use of any form of the terms “connect,” “engage,” “couple,” “attach,” or any other term describing an interaction between elements is not meant to limit the interaction to direct interaction between the elements and may also include indirect interaction between the elements described. In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to”. Unless otherwise indicated, as used throughout this document, “or” does not require mutual exclusivity.

The present disclosure relates to a perforating gun that punches holes in a casing at a downhole location. More particularly, the present disclosure relates to a detonator assembly that enables transport of the perforating gun while the detonator assembly is attached and reduces manual handling of armed perforating guns. The presently disclosed embodiments may be used in horizontal, vertical, deviated, or otherwise nonlinear wellbores in any type of subterranean formation. Embodiments may be implemented in completions operations to perforate a casing prior to production.

Referring toFIG. 1, a schematic illustration of a perforating gun assembly100is provided. The perforating gun assembly100includes a plurality of charges102that are aimed in various directions radially outward from a longitudinal axis104of the perforating gun assembly100. In other embodiments, the plurality of charges102may all be aimed in a single direction facing radially outward from the longitudinal axis104. The charges102include high explosives that are shaped to produce a pressure punch capable of punching holes in a casing within a well. In an embodiment, the pressure punch is capable of punching holes in steel, cement, rock formations, or any other surfaces that the pressure punch of the charges102may come in contact with in a downhole well. The perforating gun assembly100also includes a housing106that provides structural support to the perforating gun assembly100. Further, the housing106houses detonating cord108located within the perforating gun assembly100used to detonate the charges102. The detonating cord108is ballistically coupled to the charges102to initiate firing of the charges102.

The perforating gun assembly100may be fired in a top down manner, as indicated by arrow110, or in a bottom up manner, as indicated by arrow112. Top down fire (e.g., in the direction of the arrow110) of the perforating gun assembly100is used to have a detonation wave move from an uphole coupling114to a downhole coupling116of the perforating gun assembly100. This configuration reduces wire feed through in the gun assembly100. The top down fire configuration also reduces the ability to select fire a section of the perforating gun assembly100when multiple sections of the perforating gun assembly100are stacked. Bottom up firing of the perforating gun assembly100, for example, allows the ability to select fire each section120of the perforating gun assembly100in an order moving from a furthest downhole section120of the perforating gun assembly100to the most uphole section of the perforating gun assembly100on command. The detonation wave will move from the downhole coupling116of the perforating gun assembly100to the uphole coupling114of the perforating gun assembly100.

In a top down firing of the perforating gun assembly100, the detonating cord108may be positioned within the uphole coupling114and adjacent and/or coupled to a detonator assembly118, as discussed in detail below with reference toFIGS. 3 and 4. In a bottom up firing of the perforating gun assembly100, a signal cord may extend from a surface of a wellbore through the perforating gun assembly100to a detonator assembly118positioned at or near the downhole coupling116to provide firing signals to the detonator assembly118for firing the detonating cord108. In an embodiment, the signal cord may run within the housing106of the perforating gun assembly100to the detonator assembly118located at the downhole coupling116in a bottom up firing arrangement.

The perforating gun assembly100may include multiple sections120coupled end over end. For example, each of the sections120include an uphole coupling114and a downhole coupling116. The uphole coupling114of one section couples to a downhole coupling116of a different section. Accordingly, the perforating gun assembly100is customizable based on a number of charges102desired at a downhole location within the wellbore. Additionally, in an embodiment, only a single detonator assembly118is included for a group of sections120that make up the perforating gun assembly100. In such an embodiment, the detonator assembly118is removable and attachable to any individual section120. In another embodiment, each of the sections120include a detonator assembly118that detonates the detonating cord108of the individual section120.

FIG. 2is a schematic view of the perforating gun assembly100within a wellbore200. The perforating gun assembly100is positioned within a wellbore casing202. In an embodiment, the charges102of the perforating gun assembly100are positioned in close proximity with the wellbore casing202such that the charges102punch holes in the wellbore casing202when fired. The positioning of the charges102in relation to the wellbore casing202may be such that when the charges102punch through the wellbore casing202, effective flow communication is provided between the wellbore200and a geological formation204. As used herein, the term “close proximity” means that the charges102are positioned closer to the wellbore casing202than ten percent of a diameter of the wellbore casing202. In other embodiments, a perforating gun assembly100may be used with a diameter sufficiently smaller than a diameter of the wellbore casing202such that not all of the charges102are positioned in close proximity with the wellbore casing202. In such an embodiment, some or all of the charges102may still be capable of punching holes in the wellbore casing202when fired.

The perforating gun assembly100may be fed into the wellbore200using a wireline206. In some embodiments, the wireline206may be replaced with a slickline, or the perforating gun assembly100may be conveyed by pipe. In an embodiment, the wireline206provides a signal to the detonator assembly118coupled to the perforating gun assembly100. Upon receiving a detonate signal from the wireline206, the detonator assembly118detonates the detonating cord108. The detonating cord108detonates the charges102of the perforating gun assembly100to punch the wellbore casing202.

Referring toFIG. 3, a schematic view of the detonator assembly118in an unarmed state is depicted. As illustrated, the detonator assembly118includes a housing300. A detonator circuit board302and detonator ballistics304are stored within the housing300. Additionally, a ballistic interrupt306and an actuator308are included within the housing300. The detonator circuit board302receives control signals from electrical control paths310, which may originate from the wireline206. The control signals, which may control firing of the detonator ballistics304and actuation of the actuator308, are provided to the detonator circuit board302from an operator at the surface of the wellbore200. In another embodiment, the detonator circuit board302may control firing of the detonator ballistics304and actuation of the actuator308automatically based on pressure sensing, temperature sensing, liquid sensing, or time from deployment of the perforating gun assembly100

The actuator308controls movement of the ballistic interrupt306. As depicted inFIG. 3, the ballistic interrupt306is in a failsafe closed position. In the closed position, the ballistic interrupt306blocks ballistic transfer from the detonator ballistics304to the detonating cord108when the detonator ballistics304are fired. In blocking the ballistic transfer, the perforating gun assembly100is maintained in a mode that prevents initiation of the charges102. Accordingly, the detonator assembly118, which includes the detonator ballistics304, may be stored and transported while coupled to the perforating gun assembly100absent the chance of an unplanned discharge of the detonating cord108. When firing of the perforating gun assembly100is desired, the control signals from the electrical control paths310instruct the detonator circuit board302to control the actuator308to remove the ballistic interrupt306from a line of fire of the detonator ballistics304, as discussed in detail below with respect toFIG. 4.

The ballistic interrupt306may be made from any material suitable to block a ballistic transfer from the detonator ballistics304to the detonating cord108. For example, the ballistic interrupt306may be made from a sheet of aluminum that extends between the actuator308and the housing300and is positioned between the detonator ballistics304and the detonating cord108. Alternatively, the ballistic interrupt306may be made from other metals, a polymeric material, an elastomeric material, or any other material suitable for preventing the ballistic transfer from the detonator ballistics304to the detonating cord108. Because the ballistic interrupt306is maintained in an unarmed position until embedded digital logic is used to transition the ballistic interrupt306to an armed position, the detonator assembly118is maintained in a failsafe state until the detonator assembly118is armed.

FIG. 4is a schematic view of the detonator assembly118in an armed state. The detonator assembly118reaches the armed state when the ballistic interrupt306is removed from a line of fire400of the detonator ballistics304. The actuator308may be an electromechanical actuator with a motor that mechanically transports the ballistic interrupt306away from the line of fire400of the detonator ballistics304. In another embodiment, the actuator308may be spring actuated to maintain the ballistic interrupt306in the unarmed position ofFIG. 3until the detonator control board302provides a signal to release a spring of the actuator308to remove the ballistic interrupt306from the line of fire400. The actuator308may also include other actuator styles sufficient to remove the ballistic interrupt306from the line of fire400.

In an embodiment, the actuator308may be controlled using command and control signals from the detonator control board302. In such an embodiment, the control signals are provided to the detonator control board302by way of the electrical control paths310. In another embodiment, the actuator308may be controlled using analog control that provides control signals to the detonator control board302automatically based on pressure sensing, temperature sensing, liquid sensing, or time from deployment of the perforating gun assembly100. For example, the detonator control board302may be programmed to automatically actuate the actuator308to an armed position and subsequently fire the detonator ballistics304when the perforating gun assembly100experiences a certain pressure, temperature, liquid type, time from deployment, or any combination thereof that provides the perforating gun assembly100with an indication that the perforating gun assembly100is in an appropriate location within the wellbore200. Once the actuator308removes the ballistic interrupt306from the line of fire400, the detonator ballistics304are available to detonate the detonating cord108, which triggers firing of the charges102.

In other embodiments, the ballistic interrupt306may be replaced with a distance barrier configuration. In such an embodiment, instead of the actuator308controlling the ballistic interrupt306into and out of the line of fire400, the actuator308controls the detonator ballistics304toward or away from the detonating cord108. For example, in the embodiment illustrated inFIG. 4, the detonator ballistics304may be maintained within an quarter inch or a half inch from the detonating cord108such that the detonator ballistics304will detonate the detonating cord108upon firing of the detonator ballistics304while the ballistic interrupt306is actuated away from the line of fire400. When the distance barrier configuration is implemented in the detonator assembly118, the detonator ballistics304may be maintained in an unarmed state at a distance of a half inch to three or more inches from the detonating cord108. In such a configuration, the distance of the detonator ballistics304from the detonating cord108prevents the capability of the detonator ballistics304from detonating the detonating cord108when the detonator ballistics304are fired. When the detonator assembly118is moved into an armed state, the actuator308moves the detonator ballistics304toward the detonating cord108to a distance within a half inch of the detonating cord108. Once in the armed state, the detonator ballistics304are sufficiently close to the detonating cord108to detonate the detonating cord108upon firing of the detonator ballistics304. As used herein, the term ballistic barrier may refer to either the ballistic interrupt306or the distance barrier.

Additional embodiments include a top down firing of the detonating cord108using either a ballistic interrupt configuration, as depicted inFIGS. 3 and 4, or using the distance barrier configuration described above. In either case, the detonator assembly118may be positioned such that the detonator ballistics304fire in a downhole direction toward the detonating cord108, as opposed to in a wellbore wall facing direction as depicted inFIGS. 3 and 4. Such an embodiment may include the detonator ballistics304having the line of fire400in line with the detonating cord108, as opposed to the side fire arrangement ofFIGS. 3 and 4. In other embodiments, the detonator assembly118may also be positioned at the downhole coupling116of the perforating gun assembly100. Such a configuration may be used for a bottom up firing configuration of the perforating gun assembly100.

Additionally, in any of the embodiments, multiple sections120of the perforating gun assembly100may be stacked to provide extended perforating capabilities within the wellbore200. In embodiments with multiple sections120, a single detonator assembly118may provide the detonating force to the detonating cord108for all of the sections120of the perforating gun assembly100. In other embodiments with multiple sections120, a detonator assembly118may be deployed at each section120or at multiple sections120of the perforating gun assembly100. When multiple detonator assemblies118are deployed on a string of multiple sections120of the perforating gun assembly100, each of the detonator assemblies118may be uniquely addressable. That is, each of the detonator assemblies118may be individually controlled to initiate firing of just a single section120or group of sections120of the perforating gun assembly100without firing the entire string of sections120.

In any of the embodiments, the perforating gun assembly100or sections120of the perforating gun assembly100may be transported with the detonator assemblies118coupled to the perforating gun assembly100. Because the ballistic interrupt configuration and the distance barrier configuration prevent incidental detonation of the detonating cord108, operators are able to handle and transport the completed perforating gun assembly100.

FIG. 5is a flow-chart of a method500of operating the perforating gun assembly100. Initially, at block502, the perforating gun assembly100is run within the wellbore200to a desired location within the wellbore200. Reaching the desired location within the wellbore200may be determined based on wellbore pressure at the perforating gun assembly100, wellbore temperature at the perforating gun assembly100, run time and speed of the perforating gun assembly100, fluid composition at the perforating gun assembly100, or any other metric that enables an operator to determine a position of the perforating gun assembly100within the wellbore200.

Once the perforating gun assembly100reaches the desired location within the wellbore200, an arm command is sent to the detonator assembly118using control signals from the electrical control path310at block503. The arm command may be sent by a user remotely using the electrical control path310or by a smart device that provides the command through a predetermined setup (e.g., when a temperature, pressure, time from deployment of the perforating gun assembly100, etc. is observed at the perforating gun assembly100). The arm command is provided to the detonator control board302.

Upon receiving the arm command, the detonator assembly118is armed at block504. Arming the detonator assembly118may also occur as soon as the perforating gun assembly100is below the surface of the well within the wellbore200. Arming the detonator assembly118may involve removing the ballistic interrupt306from the line of fire400of the detonator ballistics304. Removing the ballistic interrupt306from the line of fire400enables the detonator ballistics304to detonate the detonating cord108to fire the charges102of the perforating gun assembly100. In a distance barrier configuration of the detonator assembly118, arming the detonator assembly118may involve moving the detonator ballistics304to a position close enough to the detonating cord108to detonate the detonating cord108when firing the detonator ballistics304. In such an embodiment, the detonator ballistics304may move from a distance sufficiently far away from the detonating cord108to not detonate the detonating cord108when the detonator ballistics304are fired, to the closer position that is within a distance that will detonate the detonating cord108when the detonator ballistics304are fired.

After the detonator assembly118is armed, the detonator assembly118receives a fire command at block505. The fire command may originate from the control signals received from the surface using the electrical control path310and provided to the detonator control board302. Upon receiving the fire command, the detonator assembly118is fired at block506. In another embodiment, the detonator assembly118may be fired automatically when the detonator assembly118senses that the perforating gun assembly100has moved into the desired downhole position within the wellbore200, and the detonator assembly118has transitioned into the armed state. In either embodiment, the detonator control board302provides a fire signal to the detonator ballistics304, which results in the firing of the detonator ballistics304and subsequent detonation of the detonating cord108and the charges102of the perforating gun assembly100.

The above-disclosed embodiments have been presented for purposes of illustration and to enable one of ordinary skill in the art to practice the disclosure, but the disclosure is not intended to be exhaustive or limited to the forms disclosed. Many insubstantial modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. The scope of the claims is intended to broadly cover the disclosed embodiments and any such modification. Further, the following clauses represent additional embodiments of the disclosure and should be considered within the scope of the disclosure:

Clause 1, a perforating gun assembly, comprising: a housing; at least one perforating charge disposed within the housing; a detonating cord disposed within the housing and ballistically coupled to the at least one perforating charge; and a detonator assembly disposed in line adjacent to the detonating cord, the detonator assembly comprising: a detonator; a ballistic interrupt; an actuator configured to remove the ballistic interrupt from a line of fire of the detonator; and a detonator control board configured to control the actuator and firing of the detonator.

Clause 2, the assembly of clause 1, wherein the detonator control board is configured to receive a firing signal to control firing of the detonator.

Clause 3, the assembly of clause 1 or 2, wherein the actuator removes the ballistic interrupt from the line of fire of the detonator when the perforating gun assembly is beneath a surface of a well.

Clause 4, the assembly of at least one of clauses 1-3, wherein the ballistic interrupt comprises a sheet of metal extending between the detonator and the detonating cord.

Clause 5, the assembly of at least one of clauses 1-4, wherein the detonator control board is uniquely addressable by control signals.

Clause 6, the assembly of at least one of clauses 1-5, wherein the perforating gun assembly is configured to couple to an additional perforating gun assembly.

Clause 7, the assembly of at least one of clauses 1-6, wherein the at least one perforating charge is configured to punch holes in a casing of a wellbore.

Clause 8, the assembly of at least one of clauses 1-7, wherein the ballistic interrupt comprises a distance barrier.

Clause 9, the assembly of at least one of clauses 1-8, wherein the detonator assembly is controlled using analog control that provides control signals to the detonator control board automatically based on pressure sensing, temperature sensing, liquid sensing, time from deployment of the perforating gun assembly, or any combination thereof.

Clause 10, a method to fire a perforating gun, comprising: running the perforating gun downhole within a wellbore to a desired perforating location; removing a first ballistic interrupt from a first line of fire of a first detonator of the perforating gun; and firing a first section of the perforating gun by detonating the first detonator.

Clause 11, the method of clause 10, comprising: removing a second ballistic interrupt from a second line of fire of a second detonator of the perforating gun; and firing a second section of the perforating gun by detonating the second detonator.

Clause 12, the method of clause 11, comprising: running the perforating gun within the wellbore to a second desired perforating location prior to firing the second section of the perforating gun.

Clause 13, the method of at least one of clauses 10-12, wherein the first section of the perforating gun is located further downhole than a remainder of sections of the perforating gun.

Clause 14, the method of at least one of clauses 10-13, wherein the first section of the perforating gun is located further uphole than a remainder of sections of the perforating gun.

Clause 15, the method of at least one of clauses 10-14, wherein the first detonator is uniquely addressable by control signals.

Clause 16, the method of at least one of clauses 10-15, wherein removing the first ballistic interrupt occurs when the perforating gun is below a surface of the wellbore.

Clause 17, a detonator assembly, comprising: detonator ballistics; a ballistic barrier; an actuator configured to remove the ballistic barrier from a line of fire of the detonator ballistics; and a detonator control board configured to control the actuator and firing of the detonator ballistics.

Clause 18, the detonator assembly of clause 17, wherein the ballistic barrier comprises a ballistic interrupt.

Clause 19, the detonator assembly of clause 17, wherein the ballistic barrier comprises a distance barrier.

Clause 20, the detonator assembly of clause 19, wherein removing the ballistic barrier from the line of fire of the detonator ballistics comprises moving the detonator ballistics closer to a detonating cord.

While this specification provides specific details related to certain components related to a perforating gun assembly, it may be appreciated that the list of components is illustrative only and is not intended to be exhaustive or limited to the forms disclosed. Other components related to perforating gun assemblies will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. Further, the scope of the claims is intended to broadly cover the disclosed components and any such components that are apparent to those of ordinary skill in the art.

It should be apparent from the foregoing disclosure of illustrative embodiments that significant advantages have been provided. The illustrative embodiments are not limited solely to the descriptions and illustrations included herein and are instead capable of various changes and modifications without departing from the spirit of the disclosure.