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: 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 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: A method for determining a rotational position of a rotor in a fluid pressure pulse generator of a downhole telemetry tool comprises: for at least one rotational position of the rotor, determining an expected pressure of a drilling fluid at the fluid pressure pulse generator that corresponds to the at least one rotational position; forming a rotor position map of rotor rotational positions and corresponding expected drilling fluid pressures from the at least one rotational position of the rotor and the corresponding determined expected pressure; measuring a pressure of the drilling fluid at the fluid pressure pulse generator, and determining the rotational position of the rotor at the measured pressure by associating the measured pressure to an expected pressure and corresponding rotor rotational position in the rotor position map.

Abstract: Adjustment of the angle of a bent sub or other steering feature in a drill string relative to a reference angle of a downhole sensor is facilitated by a rotatable coupling between the bent sub and the sensor. The rotatable coupling may be rotated to align the high side with a reference indicium and locked at the set angle. Rows of ceramic balls retained in circumferential channels may be provided to permit rotation while carrying tensile and compressional forces. Calibration of the sensor is facilitated and opportunities for certain measurement errors are eliminated. An embodiment provides a mechanism for locking the rotatable coupling at a desired angle. The embodiment comprises a ring with teeth that engage a downhole portion of the coupling and depressions that engage an uphole portion of the coupling.

Abstract: A downhole probe is adapted to be supported in drill string sections having different internal diameters with the use of a set of interchangeable centralizers. Each centralizer is dimensioned to snugly receive the downhole probe and to bear against the bore wall of a drill-string section. Interchangeable axial supports such as spiders may also be provided in a set. The downhole probe may comprise a slick body. As drilling progresses the downhole probe may be adapted to be received in drill string sections of varying diameters.

Abstract: A seal and seal assembly for a fluid pressure pulse generating tool. The seal comprises an annular seal section comprising an internal sealing surface and an external sealing surface; and an annular heel section. The seal assembly comprises a seal assembly housing with a longitudinally extending bore therethrough for receiving a driveshaft of the tool and the seal enclosed by the seal assembly housing and configured to surround a portion of the driveshaft. The internal sealing surface of the seal is configured to be in sealing contact with the driveshaft and the external sealing surface of the seal is configured to be in sealing contact with an internal surface of the seal assembly housing. The annular heel section of the seal is configured to provide an interference fit with the driveshaft or with the internal surface of the seal assembly housing.

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 EM uplink transmission.

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: A fluid pressure pulse generator for a telemetry tool comprising a stator and a rotor. The stator comprising a stator body and a plurality of radially extending stator projections spaced around the stator body, whereby adjacently spaced stator projections define stator flow channels extending therebetween. The rotor comprising a rotor body and a plurality of radially extending rotor projections spaced around the rotor body. The rotor projections are axially adjacent the stator projections and the rotor is rotatable relative to the stator such that the rotor projections move in and out of fluid communication with the stator flow channels to generate fluid pressure pulses in fluid flowing through the stator flow channels.

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: Method and apparatus for transmitting data to or from a downhole tool while the tool is at or near the surface using a wireless data link. A downhole tool comprising a gap sub having a tubular section with first and second longitudinally spaced-apart electrically-conducting parts that are electrically isolated from each other. An electromagnetic telemetry transmitter is connected to apply a potential difference between the first and second electrically conductive parts. A single-wire bus provides a data connection between one of the first and second electrically conductive parts and a data processor.

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 in a drill string section by centralizing features that are integral with the drill string section. A bore wall of the drill string section is fluted to provide inward contact points that support the downhole probe. The downhole probe may be supported for substantially its entire length. A vibration damping and/or electrically insulating material may optionally be provided between the downhole probe and the drill string section.

Abstract: A drill string section receives an electronics package. A flow channel extends through an aperture in the electronics package. The flow channel carries a flow of drilling fluid through the drill string section. The flow channel is sealed to a body of the drill string section. The electronics package need not be pressure-rated.

Abstract: A telemetry system useful in drilling operations receives and displays telemetry data. The telemetry system also determines and displays information regarding the status of the telemetry transmission. The telemetry system may display which data will be updated next, when the update is expected to be complete, and how reliable is the currently displayed data. The system can facilitate efficient drilling operations.

Abstract: A method for selecting a drilling fluid pressure pulse transmission frequency in a downhole telemetry tool comprises: emitting a frequency sweep wave in a drilling fluid that comprises pressure pulses over a range of frequencies and over a period of time; measuring a pressure of the drilling fluid at the telemetry tool while the frequency sweep wave is being emitted; determining a signal strength at each frequency in the range of frequencies from the measured pressure of the drilling fluid; and selecting at least one frequency in the range of frequencies that meets a selected signal strength threshold as a telemetry signal transmission frequency for the telemetry tool.

Abstract: A downhole system provides a data interface to a first downhole tool such as a steerable rotary tool. The data interface uses a close proximity data connection such as a connection between inductive loops or coils or a direct wired or optical connection. The interface provides data to a second downhole tool in a drill string section adjacent to the first downhole tool. In some embodiments data is passed to a third downhole tool that includes a telemetry transmitter. The third downhole tool may comprise a MWD (measurement while drilling) tool.

Abstract: A drill string section includes one or two tool joints that are removable from a body. Tool joints with different thread configurations may be interchangeably used with the same body. The tool joints have a compact construction that can facilitate making the drill string section short. The body overlaps with threads of one or both of the tool joints. The drill string section has non-exclusive application between a mud motor and a drill bit.

Abstract: A jig and method useful for coupling and/or uncoupling drill string sections. In some embodiments, the jig comprises a body having an outer surface for engaging a torqueing tool and a cavity extending from a first end to a second end of the body and an engagement means at the first end of the body. The engagement means may be dimensioned to non-rotationally engage an outer surface of a first end of a drill string section and the cavity may be sized to fit about a drill string section.