Abstract: An assembly for use in subsurface drilling includes a downhole probe supported by a locking mechanism with a bore of a drill string section. The probe comprises a first spider and a second spider at the uphole and downhole sections of the probe. The locking mechanism secures the probes in the bore against axial and rotational movement relative the drill string section.

Abstract: Methods and systems for testing connectivity in an EM telemetry system for transmission of a ground originating uplink EM telemetry signal. The methods and systems comprise a switch coupled to the link and configured to selectively connect the link to a test signal generator or a signal receiver, the test signal generator configured to generate a test signal and to supply it to a ground conductor, and the current within the link is measured to determine whether the link and ground conductor can properly transmit the ground originating uplink EM telemetry signal.

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: 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 measurement-while-drilling (MWD) telemetry system comprises a downhole MWD telemetry tool comprising a mud pulse (MP) telemetry unit and an electromagnetic (EM) telemetry unit. The MWD telemetry tool can be configured to transmit data in an EM-only telemetry mode using only the EM telemetry unit, in an MP-only mode using only the MP telemetry unit, or in a concurrent telemetry mode using both the EM and MP telemetry units concurrently. When transmitting data in the concurrent telemetry mode, the telemetry tool can be configured to transmit in a concurrent confirmation mode wherein the same telemetry data is transmitted by each of the EM and MP telemetry units, or in a concurrent shared mode wherein some of the telemetry data is transmitted by the EM telemetry unit, and the rest of the telemetry data is transmitted by the MP telemetry unit. The telemetry tool can be programmed to change its operating telemetry mode in response to a downlink command sent by an operator at surface.

Abstract: An assembly for use in subsurface drilling includes a downhole probe supported in a drill string section by centralizing features of a centralizer that is slidably removable from the drill string section. The centralizer may comprise a tubular body having a bore defined through it. A bore wall of the centralizer is fluted to provide inward contact points that support the downhole probe. The downhole probe may be supported for substantially its entire length. The centralizer may optionally comprise and/or be coated with a vibration damping and/or electrically insulating material.

Abstract: An assembly for use in subsurface drilling includes a downhole probe supported by a centralizer. The centralizer comprises a tubular member that extends around the downhole probe. A wall of the centralizer is fluted to provide inward contact points that support the downhole probe and outward contact points that bear against a bore wall of a section of drill string. The downhole probe may be supported for substantially its entire length.

Abstract: An assembly for use in subsurface drilling includes a drill collar section having a bore extending longitudinally through an inner surface of the drill collar section. A pocket is formed in a section of the inner surface of the drill collar section. A holster is located in the pocket and a sleeve is snuggly fitted inside the bore in order to secure the holster inside the pocket. The sleeve may be sealed to the drill collar section for example by seals such as O-rings such that the holster is sealed from the bore. O-rings may be located on one or both of the inside of the inner surface of the collar or on the outside of the sleeve.

Abstract: An apparatus for transmitting electromagnetic (EM) telemetry data from a downhole location to surface comprising: an EM signal transmitter configured to generate positive and negative polarity EM pulses corresponding to a telemetry signal; and an electronics subassembly communicative with the EM signal transmitter and comprising a processor and a memory having encoded thereon program code executable by the processor to perform a method comprising encoding measurement data into an EM telemetry signal using a modulation scheme comprising mapping a symbol set to at least one positive polarity EM pulse and one negative polarity EM pulse; and sending a control signal to the EM signal transmitter to generate EM pulses corresponding to the EM telemetry signal.

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: 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: Methods, techniques, and systems for transmitting a data frame of an electromagnetic (EM) telemetry signal to or from a downhole location can be performed using multi-channel transmissions in which at least two different channels at two different frequencies are used to send a long header and the data frame. At least a portion of the long header is transmitted at a first frequency, and at least a portion of the data frame and any remaining portion of the long header not transmitted at the first frequency are transmitted at one or more additional frequencies different from each other and the first frequency. In one example, only two channels are used: one channel is used to transmit all of the long header, another channel is used to transmit all of the data frame, and either of the channels is used to transmit an identifier identifying the type of the data frame.

Abstract: A downhole apparatus for measuring drilling fluid characteristics. The downhole apparatus may comprise one or more sensors located within a housing. The sensors may include one or more of an imaging device, a resistivity/conductivity sensor, a temperature sensor, a pressure sensor, a flowmeter and a fluid density sensor. The downhole apparatus may also include a controller for receiving measurements and/or determining optimal electromagnetic telemetry transmission settings. The downhole apparatus may also comprise a transmitter for transmitting the measurements and/or the optimal electromagnetic transmission settings. The downhole apparatus may be operated to determine optimal transmission settings for an electromagnetic telemetry system. Optimal transmission settings may include settings relating to one or more of frequency, amplitude, voltage, current, and power.

Abstract: The embodiments described herein generally relate a downhole probe assembly incorporating a Bluetooth device for wirelessly transmitting electrical information between the downhole probe assembly and a surface electronic interface such as a computer when the probe assembly is above ground. The downhole probe assembly includes sensors for sensing downhole conditions; a controller in electrical communication with the sensors and configured to receive and process information from the sensors; a housing enclosing the one or more than one sensor and the controller; the Bluetooth device in electrical communication with the controller; and an end cap assembly fitted at one end of the housing. The end cap assembly partially surrounds the Bluetooth device and is configured for transmission of the electrical information therethrough. Also described is an end cap assembly for fitting to one end of a downhole probe assembly including a transmission module mated with and electrically connected to the Bluetooth device.

Abstract: A method for using a downhole probe. The method comprises providing a probe, at least one vertical cross section of the probe having an area of at least pi inches squared. The method further comprises inserting the probe into a bore of a drill collar and passing a drilling fluid through the bore of drill collar at a flow velocity of less than 41 feet per second.

Abstract: A telemetry system with a plurality of controllers and telemetry systems, where the controllers are configured to obtain information from one or more sensors and transmit that information on one or more of the plurality of telemetry systems. The configuration of a controller may be changed so as to change which information is transmitted on a given telemetry system.

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: A gap sub comprises a female member comprising a first and second plurality of apertures, and a male member comprising a first and second plurality of cavities. A plurality of non-conductive pins may be inserted through the second plurality of apertures and the second plurality of cavities, thereby locking the relative positions of the female and male members. A plurality of conductive pins may be inserted through the first plurality of apertures and the first plurality of cavities such that there are no electrical connections between the conductive pins and the male member. A dielectric material may be inserted between the male member and the conductive pins.

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: The embodiments described herein generally relate to a fluid pressure pulse generating apparatus with a primary seal assembly, back up seal assembly and pressure compensation device. The pressure compensation device comprises a membrane support and a longitudinally extending membrane system. The membrane support has a longitudinally extending bore therethrough for receiving a driveshaft of the fluid pressure pulse generating apparatus. The longitudinally extending membrane system comprising a longitudinally extending outer membrane sleeve and a longitudinally extending inner membrane sleeve with the inner membrane sleeve positioned inside the outer membrane sleeve. The membrane system is sealed to the membrane support to allow flexing of the membrane system in response to fluid pressure on either an inner longitudinal surface of the membrane system or an outer longitudinal surface of the membrane system and to prevent fluid on the inner longitudinal surface mixing with fluid on the outer longitudinal surface.