Abstract: The embodiments described herein generally relate to a method and apparatus for providing a back up system of Directional and Inclination (D&I) information to be gathered and transmitted in addition to primary D&I sensors currently employed in industry. A downhole probe assembly including primary sensors, back up sensors and a controller is disclosed. The primary sensors comprise primary accelerometers and primary magnetometers configured to gather information relating to each of orthogonal axes X, Y and Z. The back up sensors comprise back up accelerometers configured to gather information relating to each of orthogonal axes X, Y and Z, the back up accelerometers being solid state accelerometers. The controller is in electrical communication with the primary sensors and the back up sensors.

Abstract: A downhole system comprises a main sensor, such as a gamma sensor, and a backup sensor. The backup sensor may be of a different type from the main sensor. In some embodiments the backup sensor is a high reliability sensor that may have a different sensitivity from the main sensor. The system operates both the main and backup sensors and generates calibration data for the backup sensor. If the main sensor fails the calibration data may be applied to process data from the backup sensor to yield an estimate of the data that the main sensor would have yielded if it had remained operational. The calibration data may compensate for temperature variations and/or temporal drift, for example.

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 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 for sealing a gap sub wherein injected material is used to secure a seal member in a gap. The seal member is positioned in the gap, and the material is then injected into the gap and against the seal member, seating the seal member and securing it in place once the material solidifies. The injected material is preferably electrically non-conductive.

Abstract: A sealing member or gasket for sealing a space between two adjacent surfaces, the sealing member having at least one non-helical circumferential extension or ridge configured for size-on-size or press fit engagement with a corresponding recess in at least one of the surfaces being sealed. The sealing member can be formed by molding followed by insertion between the two adjacent surfaces, or by positioning the surfaces adjacent one another and then injecting or pouring the sealing member material into the space and allowing it to solidify in place.

Abstract: The embodiments described herein generally relate to a method for detecting gamma radiation downhole using a downhole probe assembly. The method includes rotating the downhole probe assembly and measuring gamma radiation passing through a window of a gamma sensor module and hitting a gamma sensor therebelow. A gyroscope output is sampled at predetermined time intervals to indicate the speed of rotation of the downhole probe assembly. The angle of rotation of the window is calculated based on the speed of rotation of the downhole probe assembly. Each revolution of the downhole probe assembly is conceptually divided up into a plurality of bins. Measured gamma radiation is allocated to one of the plurality of bins based on the calculated angle of rotation of the window to provide a real time indication of the direction and strength of gamma radiation emitted by the formation surrounding the borehole. This information can be used for real time geosteering of the drill bit during downhole drilling.

Abstract: An electromagnetic telemetry system adjusts telemetry parameters which may include carrier frequency, signal amplitude and/or data encoding protocol to achieve reliable data transmission and to conserve power. In some embodiments, sweep signals transmit a range of carrier frequencies and the parameters are determined in part by analyzing the received sweep signals. In some embodiments, different parameters are selected automatically based on a mode of drilling.

Abstract: A range of apparatus and methods for providing local and long range data telemetry within a wellbore is described. These apparatus and methods may be combined in a wide variety of ways. In some embodiments data is transmitted across a gap in a drill string using signals of a higher frequency for which an electrical impedance of the gap or of a filter connected across the gap is low. Low-frequency EM telemetry signals may be applied across the gap. The gap and any filter connected across the gap present a high impedance to the low-frequency EM telemetry signals. The described technology may be applied for transferring sensor readings between downhole electrical packages. In some embodiments sensors are electrically connected across electrically insulating gaps in the drill string.

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: The embodiments described herein generally relate to a method for detecting gamma radiation downhole using a downhole probe assembly. The method includes rotating the downhole probe assembly and measuring gamma radiation passing through a window of a gamma sensor module and hitting a gamma sensor therebelow. A gyroscope output is sampled at predetermined time intervals to indicate the speed of rotation of the downhole probe assembly. The angle of rotation of the window is calculated based on the speed of rotation of the downhole probe assembly. Each revolution of the downhole probe assembly is conceptually divided up into a plurality of bins. Measured gamma radiation is allocated to one of the plurality of bins based on the calculated angle of rotation of the window to provide a real time indication of the direction and strength of gamma radiation emitted by the formation surrounding the borehole. This information can be used for real time geosteering of the drill bit during downhole drilling.

Abstract: A wireless communications system for a downhole drilling operation comprises surface communications equipment and a downhole telemetry tool. The surface communications equipment comprises a surface EM communications module with an EM downlink transmitter configured to transmit an EM downlink transmission at a frequency between 0.01 Hz and 0.1 Hz. The downhole telemetry tool is mountable to a drill string and has a downhole electromagnetic (EM) communications unit with an EM downlink receiver configured to receive the EM downlink transmission. The downhole EM communications unit can further comprise an EM uplink transmitter configured to transmit an EM uplink transmission at a frequency greater than 0.5 Hz, in which case the surface EM communications module further comprises an EM uplink receiver configured to receive the FIG. 1 EM uplink transmission.

Abstract: The embodiments described herein generally relate to a method and apparatus for providing a back up system of Directional and Inclination (D&I) information to be gathered and transmitted in addition to primary D&I sensors currently employed in industry. A downhole probe assembly including primary sensors, back up sensors and a controller is disclosed. The primary sensors comprise primary accelerometers and primary magnetometers configured to gather information relating to each of orthogonal axes X, Y and Z. The back up sensors comprise back up accelerometers configured to gather information relating to each of orthogonal axes X, Y and Z, the back up accelerometers being solid state accelerometers. The controller is in electrical communication with the primary sensors and the back up sensors.