Abstract: An improved method and apparatus are provided for orienting a particular well completion in accordance with azimuths determined with respect to magnetic north. The invention permits the perforating gun of a wireline tool to be properly oriented in either a vertical or non-vertical wellbore. A wireline tool is described whose lower section contains a gun section and is rotatably joined to the upper section and may be rotated about a swivel joint assembly to move independently of the upper section and in accordance with an orienting means. The rotation may be accomplished by mechanical, hydraulic or electrical means of imparting rotation. In addition, preferred embodiments of the invention include a distant display such that operators may verify directional orientation of charges prior to initiating them. Alternative embodiments are provided for practicing the invention using multiple passes into the well which involve less risk of damage to portions of the well tool.

Abstract: For use in a pulsed control system in a logging tool cooperative with a neutron generator, a pulsed ion source power supply is set forth in the preferred and illustrated embodiment. A string of field effect transistors (FET) connected between high voltage supply and ground is connected for switching the output voltage to form pulses of a desired amplitude and frequency. A timing circuit forms off and on control signals applied to pulse forming circuits. Pulse forming circuits form signals applied to gates of the FETs for timed control thereof, controlling the formation of a high voltage pulsed output signal applied to the neutron generator.

Abstract: A temperature stabilization system for a radiation detector in a well logging tool includes a temperature sensor which senses the temperature and provides a corresponding signal. Apparatus located within the logging tool and containing the radiation detector provides a controllable temperature environment for the radiation detector. A heat exchanger transfers heat from the apparatus in accordance with the temperature signal so as to stabilize the temperature in the apparatus for the radiation detector. A heat disposing device is arranged with the heat exchanger to dispose of the transferred heat.

Abstract: A system is disclosed for measuring simultaneously the formation and borehole components of thermal neutron lifetime or decay time. The borehole and formation are irradiated with 14 MEV pulsed neutrons. During the internal between neutron pulses capture gamma radiation is measured in at least four, non-overlapping, contiguous time gates. A background radiation measurement is also periodically made. Background corrected capture gamma ray measurements are combined to derive simultaneously the formation and borehole components of thermal neutron lifetime which are recorded as a function of borehole depth.

Abstract: Methods and apparatus are provided for determining the thermal neutron lifetime of earth formations in the vicinity of a well borehole. The borehole environs are irradiated with pulses of fast neutrons. Between neutron pulses capture gamma rays are detected in at least six, non-overlapping, sequential time intervals and count rate signals representative thereof are generated. Comparisons of the six count rate signals are made to determine which ones have been affected by a borehole component. Only those count rate signals not affected by the borehole component are used to determine the thermal neutron lifetime by a least-squares fitting technique.

Abstract: A pulsed neutron well logging system using a sealed off neutron generator tube is provided with a neutron output control system. The control system monitors the target beam current and compares a function of this current with a reference voltage level to develop a control signal. The control signal is used in a series regulator to control the replenisher current of the neutron generator tube.

Abstract: A pulsed neutron well logging system using a sealed off neutron generator tube is provided with a programmable digital neutron output control system. The control system monitors the target beam current and compares a function of this current with a preprogrammed control function to develop a control signal for the neutron generator. The control signal is used in a series regulator to control the average replenisher current of the neutron generator tube. The programmable digital control system of the invention also provides digital control signals as a function of time to provide ion source voltages. This arrangement may be utilized to control neutron pulses durations and repetition rates or to produce other modulated wave forms for intensity modulating the output of the neutron generator as a function of time.

Abstract: A radiation detector assembly is enclosed in a heat pipe which is positioned in a dewar flask. A thermo-electric cooler is joined to one end of the heat pipe. The heat exhaust of the thermo-electric cooler is communicated to a heat dissipation device in the form of a fin assembly. A thermistor senses the temperature at the heat pipe. When the thermistor indicates a temperature in excess of that corresponding to a reference signal, a control signal is produced by a control device to cause a power source to operate the thermo-electric cooler to remove heat from the heat pipe to the fin assembly. The vacuum within the dewar flask effectively limits the environmental heat passing to the heat pipe to radiant heat. The detector assembly and temperature stabilization system may extend to the interior of a conduit or other housing containing material whose radiation is to be detected, while the fin assembly is exposed to the atmosphere.

Abstract: An underground logging tool is equipped with a gamma ray detector encircled by a rotatable shield featuring a collimator slot. After the fluid in a formation is activated by a neutron source, the detector is used to obtain radiation count information as a function of horizontal direction as the shield is rotated. Comparison of count rate data as a function of the shield slot orientation gives information concerning the direction of the formation fluid flow. Measurements at different time intervals following the activation of the fluid, made with the shield retracted from the detector, may also be interpreted in terms of speed of horizontal fluid flow past the tool.

Abstract: Fluid in a pipeline or container at a refinery or at any of various petroleum producing operations is bombarded with neutrons, and high energy gamma rays resulting from capture of thermal neutrons are detected. The spectra of the detected gamma rays are then analyzed to determine the concentration of the element chlorine, which gives an indication of the presence and concentration of salt water in the fluid. The concentration of sulfur and the percentage gas in the fluid may be determined simultaneously with the concentration of chlorine.

Abstract: A radiation detector assembly is enclosed in a heat pipe which is positioned in a dewar flask. A thermo-electric cooler is joined to one end of the heat pipe. The heat exhaust of the thermo-electric cooler is communicated to a heat dissipation device in the form of a fin assembly. A thermistor senses the temperature at the heat pipe. When the thermistor indicates a temperature in excess of that corresponding to a reference signal, a control singal is produced by a control device to cause a power source to operate the thermo-electric cooler to remove heat from the heat pipe to the fin assembly. The vacuum within the dewar flask effectively limits the environmental heat passing to the heat pipe to radiant heat. The detector assembly and temperature stabilization system may extend to the interior of a conduit or other housing containing material whose radiation is to be detected, while the fin assembly is exposed to the atmosphere.

Abstract: Means and method for energizing and regulating a neutron generator tube having a target, an ion source and a replenisher includes providing a negative high voltage to the target and monitoring the target current. A constant current from a constant current source is divided into a shunt current and a replenisher current in accordance with the target current. The replenisher current is applied to the replenisher in a neutron generator tube so as to control the neutron output in accordance with the target current.

Abstract: Measurement of the linear flow velocity and volume flow rate of undesired behind casing water flow is provided. A well tool having a 14 MEV pulsed neutron source is used to irradiate the earth formations behind well casing with bursts of high energy neutrons. This irradiation activates elemental oxygen nuclei comprising the molecular structure of the undesired flow. Dual spaced gamma ray detectors located above or below the neutron source detect the decay of unstable isotope nitrogen 16 produced by the oxygen activation in the time intervals between the neutron bursts. Background radiation due to prompt N-.sigma. radiation is thus largely avoided. From the detected nitrogen 16 characteristic gamma rays the linear flow velocity of the undesired flow is determined. By combining this with an estimation of the distance R to the undesired flow region from the detectors, the volume flow rate V may be deduced.

Abstract: Measurement of the volume flow rate and linear flow velocity of undesired behind casing water flow is provided. A well tool having a 14 MEV neutron source is used to continuously irradiate earth formations behind well casing. The continuous neutron irradiation activates elemental oxygen nuclei comprising the molecular structure of any undesired water flow to be detected. Dual spaced gamma ray detectors located above or below the neutron source detect the decay of unstable isotope nitrogen 16 and from these indications the linear flow velocity of the undesired water flow is deduced. By then estimating the distance R to the undesired flow region the volume flow rate V may be deduced.

Abstract: Equipment for the detection of undesired behind casing water flow in a producing well is provided. A well logging sonde having a modular fluid tight structure is disclosed. Basically, three modules which when joined together form a fluid tight assemblage comprise the sonde. A first module houses a 14 MEV neutron generator and a 125 kilovolt high voltage power supply for operating the neutron generator. A second module houses dual spaced gamma ray detectors for detecting characteristic gamma rays from the decay of radioactive nitrogen 16 at two different longitudinal distances from the neutron source. A third module houses control electronics and data transmission circuits for controlling the neutron generation and receiving detected signals from dual gamma ray detectors and for transmitting data to the surface from the sonde.

Abstract: Earth formations in the vicinity of a well borehole are repetitively bombarded with bursts of high energy neutrons. A radiation detector in a sonde in the borehole senses the gamma rays induced by the capture of thermal neutrons and sends signals representative thereof to the surface. At the surface, two single channel energy analyzers, such as from 1.30 to 2.92 Mev and from 3.43 to 10.0 Mev, sense the formation thermal neutron capture gamma ray response after each neutron burst. The counts of thermal neutron capture gamma rays in these analyzers are used to distinguish between the presence of salt water and hydrocarbons, which is logged. By controlling the repetition rate of the neutron source, measured counting rates in formations with relatively large thermal neutron lifetimes are emphasized, compensating for borehole effects which could otherwise give rise to erroneous results in shale formations, which have a high boron content.

Abstract: A well-logging sonde employes a neutron generator. It has a high-voltage supply for the target of the neutron generator tube. The sonde includes an insulated high-voltage conductor for connecting the supply to target, and there is a metallic ring supported on the insulation surrounding the conductor. The ring and conductor form a capacitor that is connected to a circuit for controlling the deenergization of the high-voltage supply if an arc occurs.

Abstract: Disclosed is a well logging system for performing a continuous log of the oxygen and silicon content of earth formations in the vicinity of a well bore. A downhole sonde housing a pulsed source of 14 mev neutrons is used to irradiate earth formations in the vicinity of the well bore. A NaI (T1) detector spaced approximately 253/8 inches from the source detects gamma rays caused by neutron activation of elemental oxygen and silicon in the formations and produces voltage pulses representative of the elemental oxygen and silicon. The voltage pulses are transmitted to the surface where they are separated, corrected for background radiation and plotted continuously as a function of bore hole depth. The resultant well log traces may be interpreted in terms of lithology or formation water saturation by the use of disclosed techniques.