Abstract: Systems and methods for downhole telemetry diagnosis. A downhole telemetry system includes a plurality of joints of wired drill pipe connected end-to-end, a first repeater sub, and a second repeater sub. The first repeater sub is connected to an uphole end of the plurality of joints of wired drill pipe. The second repeater sub connected to a downhole end of the plurality of joints of wired drill pipe. The first repeater sub is configured to transmit a signal into one of the joints of wired drill pipe that is connected to the first repeater sub; to detect energy of the transmitted signal returned to the first repeater sub; to measure duration of the returned energy; and to determine an operational state of the first repeater sub based on the measured duration of the returned energy.

Abstract: Systems and methods for downhole telemetry diagnosis. A downhole telemetry system includes a plurality of joints of wired drill pipe connected end-to-end, a first repeater sub, and a second repeater sub. The first repeater sub is connected to an uphole end of the plurality of joints of wired drill pipe. The second repeater sub connected to a downhole end of the plurality of joints of wired drill pipe. The first repeater sub is configured to transmit a signal into one of the joints of wired drill pipe that is connected to the first repeater sub; to detect energy of the transmitted signal returned to the first repeater sub; to measure duration of the returned energy; and to determine an operational state of the first repeater sub based on the measured duration of the returned energy.

Abstract: A method for collecting and analyzing downhole pressure data includes disposing a plurality of pressure sensors at axially spaced locations along a drill string disposed in a well. A first data set that includes a data point for each of the pressure sensors is collected. Each data point includes a pressure value and a depth value. A value of modified equivalent circulating density (ECDm) is calculated for at least one data point. ECDm includes a static pressure component and a dynamic pressure component. Calculating the ECDm includes computing the static pressure component based on the true vertical depth of the pressure sensor, and computing the dynamic pressure component based on a second depth value that differs from the true vertical depth and is common to all the pressure sensors for which ECDm is calculated.

Abstract: An automatic, on-board system for orbiting spacecraft that controls and reduces short-term transients caused by roll momentum unloads by manipulating the states of the nutation damper through resetting one of the states in the polynomial transfer function to a value in proportion to the magnitude of the expected roll momentum unload and creating a transient equal and opposite in magnitude to that expected by the roll unload. The compensator will, of its own accord, automatically damp out the resulting transient. Thus the short-term transient is reduced without biasing the spacecraft in roll. No angle bias need be changed or removed.