Deepset receiver for drilling application

Abstract

Drilling telemetry systems and methods include a cable antenna a cable antenna in an auxiliary borehole in a subterranean formation arranged to receive electromagnetic signal transmitted from an EM tool in an adjacent wellbore in the subterranean formation. The cable antenna may include a wireline cable having a center core, an insulated electrical cable head in direct electrical communication with the center core, and an uninsulated signal receiver in direct electrical communication with electrical cable head. The uninsulated signal receiver may have an outer surface formed of a conductive material and configured to contact a natural subterranean formation.

What is claimed is: 
     
       1. A drilling telemetry system comprising:
 an electromagnetic (EM) tool sized and configured to be disposed on a drill string and introduced into a wellbore in a subterranean formation, the EM tool comprising a transmitter configured to transmit an electromagnetic signal through the subterranean formation; and 
 a cable antenna sized and configured to be introduced into an adjacent auxiliary borehole in the subterranean formation and arranged to receive the electromagnetic signal transmitted from the EM tool, the cable antenna comprising:
 a wireline cable having a center core; 
 an electrical cable head having a housing, an electrical conductor in direct electrical communication with the center core of the wireline cable and extending around a distal-most portion of the center core; and 
 an uninsulated signal receiver comprising an outer surface formed from a rigid, conductive material, the uninsulated signal receiver disposed at a distal-most end of the electrical cable head, the uninsulated signal receiver in direct electrical communication with the electrical cable head to provide uninterrupted electrical communication between the conductive outer surface and the electrical conductor of the electrical cable head, the uninsulated signal receiver being exposed to engage against the subterranean formation when the cable antenna is disposed in the adjacent auxiliary borehole. 
 
 
     
     
       2. The drilling telemetry system of  claim 1 , wherein the uninsulated signal receiver has a teardrop shape forming a bulbous head. 
     
     
       3. The drilling telemetry system of  claim 1 , wherein the uninsulated signal receiver further comprises a threaded cavity formed therein for receiving a portion of the electrical cable head. 
     
     
       4. The drilling telemetry system of  claim 1 , wherein the cable antenna further comprises a polymeric jacket around the center core, and a protective layer disposed around the polymeric jacket. 
     
     
       5. The drilling telemetry system of  claim 4 , wherein the protective layer is embedded within and fixedly attaches the electrical cable head to the wireline cable. 
     
     
       6. The drilling telemetry system of  claim 1 , wherein the conductive material of the uninsulated signal receiver comprises stainless steel. 
     
     
       7. The drilling telemetry system of  claim 1 , wherein the EM tool further comprises a power source. 
     
     
       8. The drilling telemetry system of  claim 1 , wherein the uninsulated signal receiver has a diameter of 2 to 12 inches, and a length of 3 to 18 inches. 
     
     
       9. A method of using a drilling telemetry system comprising:
 introducing an electromagnetic (EM) tool to a wellbore, the EM tool sized and configured to be disposed on a drill string, the EM tool comprising a transmitter configured to transmit an electromagnetic signal through a subterranean formation; 
 introducing a signal receiving system comprising an uninsulated signal receiver, an electrical cable head, and a wireline cable to an adjacent auxiliary borehole; 
 transmitting the EM signal from the EM tool in the wellbore; 
 detecting the transmitted EM signal with the uninsulated signal receiver disposed at a distal-most end of the signal receiving system, the uninsulated signal receiver having a conductive exterior surface in direct contact with walls of the auxiliary borehole, the conductive exterior surface being in direct electrical communication with a distal-most end of the electrical cable head to provide uninterrupted electrical communication between the conductive exterior surface and an electrical conductor of the electrical cable head, the electrical cable head being in direct electrical communication with a distal-most end of the wireline cable; and 
 communicating the detected EM signal to a signal processing system in communication with the wireline cable. 
 
     
     
       10. The method of  claim 9 , wherein said detecting the transmitted EM signal with the signal receiver comprises said detecting the transmitted EM signal only at the signal receiver. 
     
     
       11. The method of  claim 9 , further comprising performing a drilling operation, and wherein said transmitting the EM signal from the EM tool occurs during the drilling operation. 
     
     
       12. The method of  claim 9 , further comprising insulating or isolating a conductive center core in the wireline cable and the electrical conductor in the electrical cable head from contact with the walls of the auxiliary borehole. 
     
     
       13. The method of  claim 9 , wherein said communicating the detected EM signal comprises said communicating the detected EM signal through the electrical conductor in the electrical cable head and through a conductive center core of the wireline cable. 
     
     
       14. The method of  claim 9 , wherein the exterior surface of the signal receiver is in direct conductive electrical communication with the electrical conductor in the electrical cable head. 
     
     
       15. The method of  claim 9 , further comprising threading the signal receiver on to the distal-most end of the electrical cable head to place a spring-loaded contact in electrical communication with the signal receiver. 
     
     
       16. The method of  claim 9 , wherein the signal receiver has a teardrop shape forming a bulbous head. 
     
     
       17. The method of  claim 9 , wherein said transmitting the EM signal comprises said transmitting the EM signal representative of one or more detected parameters of the wellbore, an environment surrounding the wellbore, of drilling equipment, of the subterranean formation, or a combination thereof. 
     
     
       18. A drilling telemetry system comprising:
 an electromagnetic (EM) tool sized and configured to be disposed on a drill string and introduced into a wellbore in a subterranean formation, the EM tool comprising a transmitter configured to transmit an electromagnetic signal through the subterranean formation; and 
 a cable antenna sized and configured to be introduced into an adjacent auxiliary borehole in the subterranean formation and to receive the electromagnetic signal transmitted from the EM tool, the cable antenna comprising:
 a wireline cable having a center core, a polymeric insulative layer disposed in the center core, and an outer protective layer disposed in the polymeric insulative layer; 
 an electrical cable head having a housing, an electrical conductor in electrical communication with the center core of the wireline cable and extending through the housing, and a cable anchor attached to the outer protective layer and configured to secure the electrical cable head to a distal-most end of the wireline cable, the housing having a distal end having a spring-loaded contact; and 
 an uninsulated signal receiver disposed at a distal-most end of the cable antenna and formed of a rigid, conductive material having a diameter of 2 to 12 inches, the uninsulated signal receiver having a conductive outer surface exposed to engage against the subterranean formation when the cable antenna is disposed in the adjacent auxiliary borehole, the uninsulated signal receiver being in direct electrical communication with the spring-loaded contact to provide uninterrupted electrical communication between the conductive outer surface and the electrical conductor of the electrical cable head. 
 
 
     
     
       19. The drilling telemetry system of  claim 18 , wherein the uninsulated signal receiver has a teardrop shape forming a bulbous head. 
     
     
       20. The drilling telemetry system of  claim 18 , wherein the uninsulated signal receiver further comprises a threaded cavity formed therein for receiving a portion of the electrical cable head.