TRACTOR COMMUNICATION/CONTROL AND SELECT FIRE PERFORATING SWITCH SIMULATIONS

• US 20100286800A1
• Filed: 01/07/2008
• Published: 11/11/2010
• Est. Priority Date: 01/06/2007
• Status: Active Grant

• Current Assignee: Hunting Titan, Inc. (Hunting PLC)
• Original Assignee: Hunting Titan, Inc. (Hunting PLC)
• Inventors: Thomsen, Brian, Larsen, Jesper Oluf, Larsen, Kasper Juul, Lerche, Nolan C., Brooks, James E.
• Granted Patent: US 8,689,868 B2
• Time in Patent Office: Days
• US Class Current: 700/90
• CPC Class Codes: E21B 23/001 Self-propelling systems or apparatus, e.g. for moving tools within the horizontal portion of a borehole
• CPC Class Codes: E21B 43/116 Gun or shaped-charge perforators
• CPC Class Codes: E21B 43/11857 firing indication systems
• CPC Class Codes: E21B 44/00 Automatic control systems specially adapted for drilling operations, i.e. self-operating systems which function to carry out or modify a drilling operation without intervention of a human operator, e.g. computer-controlled drilling systems; Systems specially adapted for monitoring a plurality of drilling variables or conditions
• CPC Class Codes: E21B 47/024 of devices in the borehole determining slope or direction of the borehole E21B47/022
• CPC Class Codes: E21B 47/12 Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling
• CPC Class Codes: E21B 47/13 by electromagnetic energy, e.g. radio frequency

Abstract

Apparatus and methods for controlling and communicating with one or more tools in a downhole tool string including a tractor, an auxiliary tractor tool, a logging tool, a safety sub, a release mechanism, a unit containing sensors for monitoring downhole conditions, a setting tool, and a perforating gun. Control and communication are accomplished by sending signals from the surface to control switches in the control units on the tool, with redundant switches for safety, to state machines in the respective control units, each state machine returning a signal verifying switch status to the surface. The state machine need not return a signal including a unique identifier.

Claims

1. Apparatus for controlling one or more devices in a wellbore comprising:

a surface computer;

a surface controller;

a cable extending into the wellbore; and

one or more control units adapted for bi-directional communication with said surface computer and said surface controller over said cable, each said control unit comprising a state machine for identifying the status of each said control unit, the surface computer and surface controller being adapted to send a plurality of commands to the respective control units.

2. The apparatus of claim 1 wherein said surface computer and said surface controller communicate with each other via either cable or wireless connection.

3. The apparatus of claim 1 wherein said surface computer and said surface controller selectively control said control units using a sequence of commands.

4. The apparatus of claim 1 wherein each said control unit is adapted for communicating status information to said surface computer over said cable.

5. The apparatus of claim 1 wherein one or more of said control units is electrically connected in series, in parallel, or in a combination of series and parallel.

6. The apparatus of claim 1 wherein said control units access none, one, or more than one of the following:

a tractor motor;

sensors for monitoring one or more of the parameters of tractor RPM, temperature, voltage, and/or current either at the surface or at the surface while tractoring;

a mechanism for releasing a tractor from said cable;

a mechanism for releasing one or more tools in a tool string;

a unit containing sensors for monitoring downhole conditions including temperature, pressure, voltage, current, inclination, rotation, and/or acceleration;

a well logging tool;

an auxiliary tractor tool;

a device for blocking voltage;

an explosive initiator;

a perforating gun including an explosive initiator; and

/or a setting tool including an explosive initiator.

7. The apparatus of claim 1 wherein said control unit comprises one or more transistor switches, form-C switches, latching relays, or motorized piston switches.

8. The apparatus of claim 1 additionally comprising voltage-protected circuitry for controlling one or more switches in said control unit.

9. The apparatus of claim 8 wherein said voltage-protected circuitry comprises a shunting device and a fuse element.

10. The apparatus of claim 8 further comprising a circuit containing a transformer or one or more diodes, Zener diodes, triacs, or P- or N-channel FETs.

11. The apparatus of claim 1 wherein the state machine of each of said control units is provided with a pre-assigned identifier for each said control unit.

12. The apparatus of claim 11 wherein the pre-assigned identifier is contained in either a downlink, an uplink, or both downlink and uplink communications.

13. A method of switching wireline voltage between a tractor motor or the tractor output in a downhole tool string including a tractor comprising the steps of.

sending a signal to a control unit on the tractor from the surface;

processing the signal with a state machine on board the tractor for controlling the position of one or more switches located in one or more circuits connecting the wireline to either the tractor motor or a through wire that connects to the tool string; and

returning a signal validating switch action to the surface.

14. The method of claim 13 additionally comprising monitoring one or more operating parameters of the tractor during tractoring.

15. The method of claim 14 wherein the operating parameters of the tractor are monitored by power line carrier communications.

16. The method of claim 13 wherein said switches comprise transistor switches, form-C switches, latching relays, or motorized piston switches.

17. The method of claim 13 wherein signals are transmitted to and from the surface by power line carrier communications.

18. The method of claim 13 wherein the return signal comprises an identifier for each state machine.

19. The method of claim 13 wherein the downhole tool string includes one or more auxiliary tractor tools.

20. A method of switching between a safe mode for tractoring and a perforating mode for perforating in a tool string including a tractor and a perforating gun that has been lowered into a well on a wireline comprising the steps of:

sending a signal to a control unit on the tractor from the surface;

processing the signal with a state machine for controlling the position of one or more switches located in one or more circuits for connecting the wireline to either the tractor motor or a through wire connecting to the perforating gun; and

returning a signal validating switch action to the surface.

21. The method of claim 20 wherein the switches comprise transistor switches, form-C switches, latching relays, or motorized piston switches.

22. The method of claim 20 wherein the tool string includes a safety sub between the tractor and the perforating gun.

23. The method of claim 22 additionally comprising blocking wireline voltage between the safety sub and the perforating gun.

24. The method of claim 22 wherein the state machine and switches are located on the safety sub.

25. The method of claim 20 wherein the tool string includes none, one, or more than one of a safety sub, release device, and/or setting tool.

26. The method of claim 20 wherein signals are transmitted to and from the surface by power line carrier communications.

27. The method of claim 26 additionally comprising shunting the through wire to ground at a frequency higher than communication frequencies.

28. The method of claim 26 wherein perforating is done in one polarity and communications are done in the opposite polarity.

29. The method of claim 20 wherein the return signal comprises an identifier for each state machine.

30. A method for controlling one or more devices on a tool string in a wellbore with a surface computer and surface controller comprising the steps of:

sending a signal down a cable extending into the wellbore to one or more control units located on the devices in the tool string, each said control unit comprising a state machine for identifying the status of each said control unit;

processing the signal with the state machine;

controlling the position of one or more switches located on the device in the tool string when the state machine for that device processes a valid signal; and

returning a signal validating switch action to the surface computer.

31. The method of claim 30 wherein the return signal comprises an identifier for the state machine.

32. The method of claim 30 wherein signals are transmitted to and from the surface by power line carrier communications.

33. The method of claim 30 wherein the switches comprise transistor switches, form-C switches, latching relays, or motorized piston switches.

34. The method of claim 30 wherein the switches controlled by the state machine are located on either a perforating gun or setting tool.

35. An explosive initiator integrated with a control unit comprising:

means for receiving a signal from a cable to which the explosive initiator is electrically connected;

a microcontroller including a state machine for validating a signal from said signal receiving means;

a switch responsive to an output from said microcontroller when a signal is validated by the state machine; and

an explosive initiator connected to said switch.

36. The explosive initiator of claim 35 additionally comprising a switch for passing power, communication signals, or power and communication signals, to a device connected to the cable.

37. The explosive initiator of claim 35 wherein said switch is comprised of an explosive initiator switch and a wireline switch.

38. The explosive initiator of claim 35 wherein the state machine is provided with a pre-assigned identifier.

39. An apparatus for checking the function of one or more downhole tools before lowering the tools into a wellbore comprising:

a pre-check controller;

electrical connections between said pre-check controller and one or more downhole tools to be lowered into a wellbore; and

one or more control units mounted on each downhold tool adapted for bi-directional communication with said pre-check controller, each said control unit comprising a state machine for identifying the status of each said control unit, said pre-check controller being adapted to send a plurality of commands to the respective control units.

40. The apparatus of claim 39 additionally comprising a surface computer, said surface computer communicating with said pre-check controller via either a cable, a wireless connection, or a combination of cable and wireless connection.

41. The apparatus of claim 39 wherein the state machine of each of said control units is provided with a pre-assigned identifier for each said control unit.

42. The apparatus of claim 41 wherein the pre-assigned identifier is contained in either a downlink, an uplink, or both downlink and uplink communications.

43. The apparatus of claim 39 wherein the switches controlled by the state machine are located on either a perforating gun or setting tool.

44. A method for checking one or more devices in a tool string before lowering the tool string into a wellbore comprising the steps of:

sending a signal to one or more control units located on the devices in the tool string, each said control unit comprising a state machine for identifying the status of each said control unit;

processing the signal with the state machine;

controlling the position of one or more switches located on the device in the tool string when the state machine for that device processes a valid signal; and

returning a signal validating switch action from the control unit.

45. The method of claim 44 wherein the state machine of each of said control units is provided with a pre-assigned identifier for each said control unit.