Apparatus and method for selective actuation of downhole tools
View Patent ↗The present invention provides systems, methods and devices for selectively firing a gun train formed of a plurality of guns. Conventionally, the guns each include a detonator assembly that detonates upon receiving a firing signal transmitted by a surface source. In one embodiment of the present invention, an operator provided in the gun train selectively couples one or more of the guns to the signal transmission medium. The operator has an safe state wherein the operator isolates the gun from the firing signal and an armed state wherein the operator enable the transmission of the firing signal to the gun. A control signal is used to move operator between the safe state and the armed state. In some embodiments, two or more guns are each provided with a separate operator. In other embodiments, one operator can selectively engage two or more guns.
1. An apparatus for perforating a wellbore, comprising:
(a) a gun train formed by serially coupling a plurality of guns,
(b) a detonator assembly associated with each gun;
(c) a signal transmission medium for conveying a firing signal to each detonator assembly from a surface controller, the detonator assembly detonating the associated gun in response to the firing signal;
(d) an operator interposed between the signal transmission medium and at least one detonator assembly to enable selective transmission of the firing signal from the surface controller to the at least one detonator assembly, the operator allowing transmission of the firing signal to the at least one detonator assembly only in response to a control signal transmitted from the surface controller; and
(e) a wiring harness having a contact plate coupled to the at least one detonator assembly, wherein the operator selectively engages the contact plate.
2. The apparatus according to claim 1 , wherein the operator selectively substantially isolates the at least one detonator assembly by forming a gap in a signal path between the detonator and the signal transmission medium.
3. The apparatus according to claim 1 , wherein the operator selectively forms a signal conducting path with the detonator, the firing signal being conveyed to the at least one detonator via the signal conducting path.
4. The apparatus according to claim 1 , wherein the operator includes a motor for driving a shaft into contact with the detonator upon receiving the control signal.
5. The apparatus according to claim 1 , wherein the signal transmission medium includes an electrical wiring bundle extending from the surface controller to the gun train.
6. An apparatus for providing selective firing of a gun train formed of a plurality of guns, each gun detonating upon receiving a firing signal conveyed by a signal transmission medium, the apparatus comprising:
(a) an operator selectively coupling at least one gun of the gun train to a signal transmission medium, the operator having a safe state wherein the operator isolates the gun from the firing signal conveyed by the signal transmission medium and an armed state wherein the operator forms a signal path between the gun and the signal transmission medium to thereby convey the firing signal to the gun, the operator moving from a safe state to an armed state upon receiving a control signal from a surface source, wherein the firing signal is an electrical signal of one polarity and the control signal is an electrical signal of a polarity opposite to that of the firing signal.
7. The apparatus according to claim 6 , wherein the operator includes a conductive member that selectively engages the detonator.
8. The apparatus according to claim 6 , wherein the operator includes a motor for moving a conductive member into engagement with the at least one gun to thereby form a signal path for transmitting the firing signal to the at least one gun.
9. The apparatus according to claim 6 further comprising at least two operators, each operator being associated with at least one gun.
10. The apparatus according to claim 6 , wherein the operator is associated with at least two guns.
11. A method for perforating a wellbore, comprising:
(a) forming a gun train by serially coupling a plurality of guns, each gun being coupled to a detonator assembly;
(b) providing a signal transmission medium for conveying a firing signal to each the detonator, each the detonator assembly detonating an associated gun in response to the firing signal;
(c) connecting a first gun of the plurality of guns to the signal transmission medium with an operator, the operator being configured to selectively engage a first detonator assembly coupled to the first gun, the operator initially being disengaged from the first detonator assembly;
(d) conveying the gun train into the wellbore;
(e) positioning the gun train in the wellbore at a depth corresponding to a section of the wellbore to be perforated;
(f) transmitting a control signal to the operator from the surface, the operator engaging the first detonator assembly in response to the control signal;
(g) transmitting a firing signal to detonate the first detonator assembly and thereby fire the first gun, and
(h) transmitting a third control signal to the first operator, the first operator disengaging from the first detonator upon receiving the third control signal.
12. The method according to claim 11 , wherein the operator connects at least two guns to the signal transmission medium.
13. The method according to claim 11 further comprising:
(a) connecting a second gun to the signal conveyance medium using a second operator;
(b) transmitting a second control signal to the second operator from the surface, the second operator engaging a second detonator assembly in response to the second control signal; and
(c) transmitting a second firing signal to detonate the second detonator assembly and thereby fire the second gun.
14. The method according to claim 13 further comprising transmitting the first and second firing signal at one of: (i) sequentially, and (ii) concurrently.
15. The method according to claim 13 further comprising repositioning the gun train after transmitting the first firing signal.
16. The method according to claim 11 , wherein the first firing signal is one of: (i) an electrical signal, (ii) an acoustic signal, (iii) a pressure signal, (iv) a thermal signal, and (v) a ballistic signal.
17. The method according to claim 11 , wherein the first control signal is one of: (i) an electrical signal, (ii) an acoustic signal, (iii) a pressure signal, (iv) a thermal signal, and (v) a ballistic signal.
18. An apparatus for providing selective firing of a gun train formed of a plurality of guns, each gun detonating upon receiving a firing signal conveyed by a signal transmission medium, the apparatus comprising:
(a) an operator selectively coupling at least one gun of the gun train to a signal transmission medium, the operator having a safe state wherein the operator isolates the gun from the firing signal conveyed by the signal transmission medium and an armed state wherein the operator forms a signal path between the gun and the signal transmission medium to thereby convey the firing signal to the gun, the operator moving from a safe state to an armed state upon receiving a control signal from a surface source, wherein the signal transmission medium is an electrical wiring bundle adapted to convey the firing signal and the control signal and the operator includes an electrical motor responsive to the control signal.