Abstract: A test system and method for in line testing of shock suppressor shut-off valves is provided. Vacuum and fluid canisters are mounted to a backpack that can be carried by maintenance personnel to the operating locations of shock suppressors. The fluid canister contains a fluid for being driven through the shut-off valves of the shock suppressor during testing. Fluid lines interconnect the canisters and the shock suppressor. A valve assembly is disposed within the fluid lines for regulating the rate of flow of the fluid from the fluid canister to the shock suppressor. The system further includes structure disposed within the fluid lines for evacuating the fluid lines and the valve assembly prior to testing of the shut-off valves.

Abstract: An automatic control selector responds to demand conditions to select the proper control mode for a compressor system that includes a compressor operable in a plurality of control modes for alternately controlling the compressor according to the demand conditions on the system. Upon the detection of heavy demand conditions and upon the detection of light demand conditions, the automatic control selector automatically switches the system into an appropriate control mode.

Abstract: A servo valve controls the rate and direction of flow of a hydraulic fluid from a fluid power system to impart reciprocating motion to the piston of a hydraulically driven motor. An outer sleeve member of the servo valve has entry and exit ports connected to the source of fluid power and motor control ports connected to the hydraulically driven motor. A slider member is positioned within a cylindrical opening through the sleeve member and includes fluid chambers within the slider for alternating the direction of fluid flowing to the hydraulically driven motor by rotating the slider member. The rate of fluid flow is controlled by the lateral movement of the slider within the sleeve member.

Abstract: Well is first logged with gamma ray detection system to provide a base log. Fluid containing salt of potassium, uranium or thorium is then injected into the well opposite the interval of interest. When the well head pressure is increased, some of the injected fluid will move into the fracture or other highly permeable localized zones. The gamma ray detection system is then run again one or more times through the well to provide a log which is compared with the base log. The fracture is detected by localized drastically higher readings observed on the repeat run of the gamma ray detection logging system.

Abstract: Well is first logged with gamma ray detection system to provide a base log. Fluid containing salt of potassium, uranium or thorium is then injected into the well opposite the interval of interest. When the well head pressure is increased, some of the injected fluid will move into the channel which is allowing fluid to move between different zones in the formations around the well. The gamma ray detection system is then again run through the well to provide a log which is compared with the base log. The channel between zones is detected by localized drastically higher readings observed on the repeat run of the gamma ray detection logging system.

Abstract: A well logging instrument is attached at its first end to a well logging cable and is connected at its second end through a flex joint to a shaft section which through another flex joint is connected at its lower end to a centralizing section. As the well logging instrument traverses an earth borehole, the lower centralizer section maintains the guide nose of the centralizer section away from the ledges encountered along the borehole walls and a shaft flexibly connected between the well logging instrument and the centralizer section ties the gravity decentralized logging instrument to the lower centralizing section and steers the lower guide nose away from the ledges which are encountered.

Abstract: After drilling an earth borehole, the drill pipe and drill bit are removed from the borehole and the drill pipe is reinserted into the borehole. A flexible hose such as a fire hose, and having a retro-nozzle at its lower end, is then pumped down through the interior of the drill pipe and a portion of the hose is pumped out through the end of the drill pipe for a desired distance. A well logging instrument is pumped through the flexible hose which extends down past the bottom of the drill pipe and well logging operations are performed through the flexible hose. In very hot wells, the drilling mud or other circulating fluid can continue to be pumped through the flexible hose to provide cooling of the well logging instrument.

Abstract: A well logging instrument has a fluid chamber at its lower end and a plurality of controlled flow orifices leading from the chamber to the exterior of the instrument. A piston within the chamber, having a spring at its upper end, forces a friction-reduction agent from the chamber through the flow-controlled orifices into the earth borehole to facilitate the movement of the well logging instrument through the borehole. The upper portion of the fluid chamber, above the piston, is also ported to the fluid within the borehole to equalize the pressure across the piston. In an alternative embodiment of the invention, the acceleration of the borehole instrument creates a velocity signal which is compared with the velocity of the logging cable at the earth's surface and upon a sufficient difference in velocity, the friction-reduction agent is caused to be ported into the earth borehole.

Abstract: In order to prevent late arriving and higher amplitude shear waves from saturating the subsurface amplifier, the amplitude of each succeeding positive half cycle of the earlier arriving compressional wave is measured and a negative feedback is supplied to the amplifier if the measured amplitude exceeds 50% of full scale. Circuitry is provided for utilization of a two transmitter, two receiver system using the same type of negative feedback to control the gain of the subsurface amplifier.

Abstract: A logging instrument contains a pulsed neutron source and a pair of radiation detectors spaced along the length of the instrument. The radiation detectors are gated differently from each other to provide an indication of formation porosity which is substantially independent of the formation salinity. In the preferred embodiment, the electrical signals indicative of radiation detected by the long-spaced detector are gated for almost the entire interval between neutron pulses and the short-spaced signals are gated for a significantly smaller time interval which commences soon after the termination of a given neutron burst. The signals from the two detectors are combined in a ratio circuit for determination of porosity.

Abstract: A pulsed neutron generator in a well logging instrument is pulsed at a clock frequency of 20 KHz. Inelastic scatter gamma rays are detected during a first time interval coinciding with the neutron source being on and capture gamma rays are measured during a second interval subsequent to the end of each neutron burst. Only a single detected pulse, assuming detection occurs, is transmitted during each of the two detection intervals. Sync pulses are generated in the well logging instrument scaled down to a frequency of 200 Hz for transmission to the earth's surface. At the earth's surface, the scaled-down sync pulses are applied to a phase-locked loop system for regenerating the sync pulses to the same frequency as that of the clock frequency used to pulse the neutron source and to open the detection gates in the borehole instrument.

Abstract: A pulsed neutron generator in a well logging instrument is pulsed at a clock frequency of 20 KHz. Inelastic scatter gamma rays are detected during a first time interval coinciding with the neutron source being on and capture gamma rays are measured during a second interval subsequent to the end of each neutron burst. Only a single detected pulse, assuming detection occurs, is transmitted during each of the two detection intervals. Sync pulses are generated in the well logging instrument scaled down to a frequency of 200 Hz for transmission to the earth's surface. At the earth's surface, the scaled-down sync pulses are applied to a phase-locked loop system for regenerating the sync pulses to the same frequency as that of the clock frequency used to pulse the neutron source and to open the detection gates in the borehole instrument.

Abstract: A pulsed neutron generator in a well logging instrument is pulsed at a clock frequency of 20 KHz. Inelastic scatter gamma rays are detected during a first time interval coinciding with the neutron source being on and capture gamma rays are measured during a second interval subsequent to the end of each neutron burst. Only a single detected pulse, assuming detection occurs, is transmitted during each of the two detection intervals. Sync pulses are generated in the well logging instrument scaled down to a frequency of 200 Hz for transmission to the earth's surface. At the earth's surface, the scaled-down sync pulses are applied to a phase-locked loop system for regenerating the sync pulses to the same frequency as that of the clock frequency used to pulse the neutron source and to open the detection gates in the borehole instrument.

Abstract: A mechanical arm linkage for use in wellbore measuring instruments provides a linear correcting linkage assembly for pivotally connecting a sensor in linear sliding relationship to a non-linearly articulated moving arm member.