Abstract: A gap sub assembly for electromagnetic telemetry used in downhole drilling. The gap sub comprises a female part comprising a female mating section and a male part comprising a male mating section. The male mating section is matingly received within the female mating section and electrically isolated therefrom. One or more electrically insulating bodies secure the male part axially and torsionally relative to the female part. The electrically insulating bodies also electrically isolate the male part from the female part. The electrically insulating bodies can be installed through apertures in the female part or at least some of the electrically insulating bodies can be installed before the male mating section is inserted into the female mating section. The electrically insulating bodies can be held in place on the male mating section using a retention apparatus such as a ring, a scarf, pods or an adhesive.

Abstract: One or more seals may be provided in a gap sub to prevent the ingress of drilling fluid into an insulating gap between a male member of the gap sub and a female member of the gap sub. A first seal may comprise an internal gap sub seal provided near the tip of the male member of the gap sub. A second seal may comprise an external gap sub seal provided near the tip of the female member of the gap sub. The first and second seals may comprise non-conductive materials. The first and second seals may each comprise one or more O-rings. The first and second seals may comprise one or more lips, protrusions or flanges to engage the male and/or female members of the gap sub for maintaining contact with the male and/or female members during deformation of the gap sub.

Abstract: A gap sub assembly for electromagnetic telemetry used in downhole drilling. The gap sub comprises a female part comprising a female mating section and a male part comprising a male mating section. The male mating section is matingly received within the female mating section and electrically isolated therefrom. One or more electrically insulating bodies secure the male part axially and torsionally relative to the female part. The electrically insulating bodies also electrically isolate the male part from the female part. The electrically insulating bodies can be installed through apertures in the female part or at least some of the electrically insulating bodies can be installed before the male mating section is inserted into the female mating section. The electrically insulating bodies can be held in place on the male mating section using a retention apparatus such as a ring, a scarf, pods or an adhesive.

Abstract: An assembly for receiving telemetry signals from downhole equipment is located at a top end of a drill string above a drill rig floor. The assembly may be configured to receive multiple types of telemetry signals, for example, two or more of electromagnetic telemetry, mud pulse telemetry and drill string acoustic telemetry signals. The assembly may comprise a cap comprising a coupling and an end separated by an electrically-insulating gap region. The end of the cap may be connected to a grounding system for the drill rig.

Abstract: An insulating collar for a gap sub assembly for electromagnetic (EM) telemetry used in downhole drilling is disclosed. The gap sub assembly comprises a female member comprising a female mating section and a male member comprising a male mating section and a gap section. The male mating section is matingly received within the female mating section and electrically isolated therefrom. The insulating collar is positioned on the gap section. The collar is made up of a framework with a plurality of discrete bodies spaced about the framework and a portion of each of the discrete bodies protrudes above the framework. Either the framework or the discrete bodies are made of an electrical insulator material to electrically isolate one end of the collar from the other end of the collar. The collar therefore electrically isolates the male member from the female member and the male member, female member and insulating collar function as the “gap sub” for EM telemetry.

Abstract: An assembly for receiving telemetry signals from downhole equipment is located at a top end of a drill string above a drill rig floor. The assembly may be configured to receive multiple types of telemetry signals, for example, two or more of electromagnetic telemetry, mud pulse telemetry and drill string acoustic telemetry signals. The assembly may comprise a cap comprising a coupling and an end separated by an electrically-insulating gap region. The end of the cap may be connected to a grounding system for the drill rig.

Abstract: An electromagnetic telemetry signal generating assembly comprises a first section of drill string, a second section of drill string, a gap sub configured to insulate the first section from the second section, and a power source configured to provide a first voltage to a control circuit. The control circuit is configured to drive a second voltage between the sections of drill string. The gap sub provides a gap of at least 12 inches (30 cm). The second voltage may be different than the first voltage.

Abstract: A telemetry method transmits data by MP telemetry to a telemetry relay system which retransmits the data by EM telemetry. The method avoids the need to incorporate MP telemetry pressure transducers into rig equipment and permits telemetry from regions unfavorable for EM telemetry because of depth and/or characteristics surrounding formations.

Abstract: An insulating collar for a gap sub assembly for electromagnetic (EM) telemetry used in downhole drilling is disclosed. The gap sub assembly comprises a female member comprising a female mating section and a male member comprising a male mating section and a gap section. The male mating section is matingly received within the female mating section and electrically isolated therefrom. The insulating collar is positioned on the gap section. The collar is made up of a framework with a plurality of discrete bodies spaced about the framework and a portion of each of the discrete bodies protrudes above the framework. Either the framework or the discrete bodies are made of an electrical insulator material to electrically isolate one end of the collar from the other end of the collar. The collar therefore electrically isolates the male member from the female member and the male member, female member and insulating collar function as the “gap sub” for EM telemetry.

Abstract: A housing for a mud motor is disclosed. The housing comprises a female member comprising a female mating section and a male member comprising a male mating section and a housing section. The male mating section is matingly received within the female mating section. The collar is positioned on the housing section. The collar is made up of a framework with a plurality of discrete bodies spaced about the framework and a portion of each of the discrete bodies protrudes above the framework.

Abstract: An electromagnetic telemetry signal generating assembly comprises a first section of drill string, a second section of drill string, a gap sub configured to insulate the first section from the second section, and a power source configured to provide a first voltage to a control circuit. The control circuit is configured to drive a second voltage between the sections of drill string. The gap sub provides a gap of at least 12 inches (30 cm). The second voltage may be different than the first voltage.

Abstract: An assembly for receiving telemetry signals from downhole equipment is located at a top end of a drill string above a drill rig floor. The assembly may be configured to receive multiple types of telemetry signals, for example, two or more of electromagnetic telemetry, mud pulse telemetry and drill string acoustic telemetry signals. The assembly may comprise a cap comprising a coupling and an end separated by an electrically insulating gap region. The end of the cap may be connected to a grounding system for the drill rig.

Abstract: A method and apparatus for joining first and second bodies coaxially together to resist relative axial and rotational movement between the bodies. A male portion of the first body is received in a complementary female portion of the second body, and the male and female portions are aligned axially on a common axis such that respective cooperating grooves in opposing cylindrical or tapered complementary surfaces of the male and female portions are aligned to form a plurality of passageways or a passageway having a plurality of passageway portions, between the opposing cylindrical or tapered complementary surfaces. At least two of the passageways or at least two of the passageway portions are disposed at different angles to the common axis.

Abstract: A method and apparatus for joining first and second bodies coaxially together to resist relative axial and rotational movement between the bodies. A male portion of the first body is received in a complementary female portion of the second body, and the male and female portions are aligned axially on a common axis such that respective cooperating grooves in opposing cylindrical or tapered complementary surfaces of the male and female portions are aligned to form a plurality of passageways or a passageway having a plurality of passageway portions, between the opposing cylindrical or tapered complementary surfaces. At least two of the passageways or at least two of the passageway portions are disposed at different angles to the common axis.