Abstract: A system and method for downhole power delivery. In one embodiment, the system delivers computer-regulated downhole power voltages, and may be configured to customize signal waveforms and power allocation on the various independent signal transmission modes to maximize the power capacity of the logging cable subject to its maximum voltage rating. In one embodiment, the system includes a standard multiconductor logging cable which supports orthogonal signal transmission modes on circumferentially spaced insulated conductors. A high-power power source on the surface is coupled to the insulated conductors in the cable to drive a power signal on the lowest impedance signal transmission mode. The system may further include multiple power sources operating on different independent signal transmission modes, and may also include multiple telemetry channels which share the power transmission modes via frequency multiplexing.

Abstract: A system and method for downhole power delivery. In one embodiment, the system delivers computer-regulated downhole power voltages, and may be configured to customize signal waveforms and power allocation on the various independent signal transmission modes to maximize the power capacity of the logging cable subject to its maximum voltage rating. In one embodiment, the system includes a standard multiconductor logging cable which supports orthogonal signal transmission modes on circumferentially spaced insulated conductors. A high-power power source on the surface is coupled to the insulated conductors in the cable to drive a power signal on the lowest impedance signal transmission mode. The system may further include multiple power sources operating on different independent signal transmission modes, and may also include multiple telemetry channels which share the power transmission modes via frequency multiplexing.

Abstract: A system and method is described for safely and economically providing up to 1800 watts to downhole equipment over existing logging cables. In one embodiment, the system includes a standard multiconductor logging cable which supports orthogonal signal transmission modes on circumferentially spaced insulated conductors. A high-power power source on the surface is coupled to the insulated conductors in the cable to drive a power signal on the lowest impedance signal transmission mode. Bearing in mind that high-power electrical currents can present a safety hazard, system safety may be enhanced by the addition of a reliable current imbalance detector configured to shut down all power sources when currents in the insulated conductors don't add up to zero. The system may further include multiple power sources operating on different independent signal transmission modes, and may also include multiple telemetry channels which share the power transmission modes via frequency multiplexing.

Abstract: A formation tester is set forth. It incorporates a probe having a surrounding elastomeric seal and snorkel for extension into formations. The probe connects with a sample line into the formation tester. On the sample line, a pressure sensor responds to pressure observed in the sample line and provides a signal for use in control of a motor controller opening and closing relative to hard valve elements and valve seats in a choking action to control flow in the sample line. The sample line then goes to a soft seat valve assembly having a valve element and a seat which delivers controlled sample flow into a chamber for storage within the formation tester.

Abstract: For use in a formation testing tool adapted to be lowered into a borehole on a logging cable, apparatus is set forth which conducts formation measurements including extension of a snorkel into a formation of interest, initiating a drawdown beginning at a first time and terminating at a second time. The flow rate in the drawdown is measured. The present apparatus and method further determine a Horner Plot for that particular formation, and measure the slope of the Horner Plot and also extend the Horner Plot to thereby obtain the intercept representative of final formation pressure after build-up. A relationship is evaluated, and computer circuitry for determining permeability responds to the slope of the Horner Plot, formation fluid viscosity, pretest flow rate and formation thickness to yield permeability.

Abstract: For use with casing having flush joint collars, a detection system is set forth which comprises a tool body made of nonmagnetic material and enclosing abutted first, second and third permanent magnets. The magnets are axially aligned, abutted so that opposing poles are in contact with one another, thereby forming a magnetic field from the center magnet which is focused out into the metal of the casing. Separate detection coils spaced along the tool body detect signals induced by variations in magnetic reluctance as the tool traverses the cased well.