Sneak path eliminator for diode multiplexed control of downhole well tools

• US 8,757,278 B2
• Filed: 06/02/2010
• Issued: 06/24/2014
• Est. Priority Date: 09/09/2008
• Status: Active Grant

• Current Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Original Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Inventors: Smithson, Mitchell C.
• Primary Examiner(s): Gay, Jennifer H
• Assistant Examiner(s): GITLIN, ELIZABETH C GOTTLIEB
• Application Number:
  US12/792,298
• Publication Number:
  US 20100237698A1
• Time in Patent Office: 1,483 Days
• Field of Search: 166/381, 166/373, 166/651, 166/316
• US Class Current: 166/381
• CPC Class Codes: E21B 23/00 Apparatus for displacing, setting, locking, releasing or removing tools, packers or the like in boreholes or wells setting of casings, screens or liners E21B43/10
• CPC Class Codes: E21B 34/06 in wells
• CPC Class Codes: E21B 34/066 electrically actuated
• CPC Class Codes: E21B 34/10 operated by control fluid supplied from outside the borehole
• CPC Class Codes: E21B 41/00 Equipment or details not covered by groups E21B15/00 - E21B40/00
• 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 47/125 using earth as an electrical conductor by electromagnetic energy E21B47/13

Abstract

Sneak path elimination in diode multiplexed control of downhole well tools. A system for selectively actuating multiple well tools includes a control device for each tool, a well tool being operable by selecting a respective control device; conductors connected to the control devices, which are selectable by applying a predetermined voltage across a respective predetermined pair of the conductors; and at least one lockout device for each control device, the lockout devices preventing current from flowing through the respective control devices when voltage across the respective predetermined pair of the conductors is less than a predetermined minimum. A method includes selecting a well tools for actuation by applying a predetermined minimum voltage to a set of conductors; and preventing actuation of another well tool when the predetermined minimum voltage is not applied across another set of conductors, at least one conductor being common to the two sets of conductors.

Claims

1. A system for selectively actuating from a remote location multiple downhole well tools in a well, the system comprising:

first, second, and third conductors;

a first control device which controls actuation of a first well tool, wherein the first control device is connected between the first and second conductors, and wherein the first control device is not electrically connected to the third conductor;

a second control device which controls actuation of a second well tool, wherein the second control device is connected between the first and third conductors, and wherein the second control device is not electrically connected to the second conductor,

whereby a respective one of the first and second control devices is selected by applying at least a predetermined minimum voltage potential across a respective pair of the conductors; and

first and second lockout devices, whereby current is prevented from flowing through the second control device when the first control device is selected, and whereby current is prevented from flowing through the first control device when the second control device is selected.

2. The system of claim 1, wherein at least one of the lockout devices includes a relay with a switch, and wherein the relay closes the switch, thereby permitting current flow through the selected control device when the predetermined minimum voltage potential is applied across the respective pair of the conductors.

3. The system of claim 1, wherein at least one of the lockout devices includes a thyristor, and wherein the thyristor permits current flow from a source to a drain of the thyristor, thereby permitting current flow through the selected control device when the predetermined minimum voltage potential is applied across the respective pair of the conductors.

4. The system of claim 1, wherein at least one of the lockout devices includes a zener diode, and wherein current flows through the zener diode, thereby permitting current flow through the selected control device when the predetermined minimum voltage potential is applied across the respective pair of the conductors.

5. The system of claim 1, wherein at least one of the lockout devices includes a transistor, and wherein the transistor permits current flow from a source to a drain of the transistor, thereby permitting current flow through the selected control device when the predetermined minimum voltage potential is applied across the respective pair of the conductors.

6. The system of claim 1, wherein at least one of the lockout devices includes a relay with a switch, and wherein the switch remains open unless the predetermined minimum voltage potential is applied across the respective pair of the conductors.

7. The system of claim 1, wherein at least one of the lockout devices includes a thyristor, and wherein current is prevented from flowing unless the predetermined minimum voltage potential is applied across the respective pair of the conductors.

8. The system of claim 1, wherein at least one of the lockout devices includes a zener diode, and wherein current is prevented from flowing unless the predetermined minimum voltage potential is applied across the respective pair of the conductors.

9. The system of claim 1, wherein at least one of the lockout devices includes a transistor, and wherein current is prevented from flowing unless the predetermined minimum voltage potential is applied across the respective pair of the conductors.

10. A method of selectively actuating from a remote location multiple downhole well tools in a well, the method comprising the steps of:

connecting a first control device of a first well tool between first and second conductors, wherein the first well tool is selected for actuation via the first and second conductors;

connecting a second control device of a second well tool between the first conductor and a third conductor, wherein the second well tool is selected for actuation via the first and third conductors;

selecting a respective one of the first and second well tools for actuation by applying at least a predetermined minimum voltage potential across a respective pair of the conductors; and

providing first and second lockout devices, thereby fully preventing current flow through the first control device of the first well tool when the second well tool is selected for actuation, and thereby fully preventing current flow through the second control device of the second well tool when the first well tool is selected for actuation.

11. The method of claim 10, wherein the selecting step further comprises permitting current flow through the respective control device of the selected well tool when the predetermined minimum voltage potential is applied across the respective pair of the conductors.

12. The method of claim 11, wherein the current flow permitting step further comprises actuating a relay to thereby close a switch, thereby permitting current flow through the respective control device when the predetermined minimum voltage potential is applied across the respective pair of the conductors.

13. The method of claim 11, wherein the current flow permitting step further comprises permitting current flow from a source to a drain of a thyristor, thereby permitting current flow through the respective control device when the predetermined minimum voltage potential is applied across the respective pair of the conductors.

14. The method of claim 11, wherein the current flow permitting step further comprises permitting current flow through a zener diode, thereby permitting current flow through the respective control device when the predetermined minimum voltage potential is applied across the respective pair of the conductors.

15. The method of claim 11, wherein the current flow permitting step further comprises permitting current flow from a source to a drain of a transistor, thereby permitting current flow through the respective control device when the predetermined minimum voltage potential is applied across the respective pair of the conductors.