Abstract: A modular sonde may be configured in various ways for measurements in open or cased boreholes. The sonde is conveyed on an electric wireline with or without a coiled tubing for conveying hydraulic energy from the surface. Modules common to the configurations include telemetry electronics, orientation, hydraulic energy accumulator, fluid chambers, hydraulic power, pumpout, and flow control. Each configuration has a stress/rheology module suited to the borehole situation. An open-hole sonde configuration has a stress/rheology module with an instrumented, inflatable packer module, an orienting module, and a probe module. A second open-hole sonde configuration has a stress/rheology module with an instrumented straddle-packer assembly. A cased-hole sonde configuration has a gunblock assembly, a gunblock orienting module hydraulics for formation pretest and hydraulics for stressing the formation to obtain data related to formation stress characteristics.

Abstract: A logging-while-drilling apparatus includes a source of exciting radiation, means for illuminating the borehole wall with the radiation and means for detecting radiation returning from the borehole resulting from illumination with the exciting radiation. A bottom hole assembly (BHA) incorporating such apparatus can comprise a drill bit, one or more stabilizers and one or more drill collars and the source and illuminating and detecting means can be located in one of these or distributed therebetween according to requirements. A window can be provided to allow illumination of the borehole and detection of returning radiation.

Abstract: A high voltage DC source for a particle accelerator is an inductively charged, coaxial nest of capacitors. The nest of capacitors comprises coaxial tubes of insulation, one inside the next, and an inductive coil. The inductive coil is wound in several layers between the tubes of insulation. The nest of capacitors is inductively charged by a high turns ratio transformer. The transformer's primary coil is wound the length of the accelerator outside the nested capacitors. The transformer's secondary coil comprises the inductive coil layered between the tubes of insulation. Diodes in series with the secondary coil produce the DC signal of the source.

Abstract: A method of determining the resistivity of an underground formation surrounding a cased borehole including the steps of: a) passing a current along a first pan of the casing and measuring the voltage; b) passing a current along a second part of the casing and measuring the voltage, the second part being spaced from the first part by an intermediate region; c) measuring voltages between the first part of the casing and a point in the intermediate region and between the second part of the casing and the same point; and d) using the measured voltages to derive the resistivity of the formation.

Abstract: An apparatus for electrolyzing fluids is disclosed. The resulting electrolyzed fluids are particularly suited for treating physiological materials such as whole blood, plasma, or cell isolates in order to reduce the effect of harmful microorganisms. A container holds the fluid and a power supply provides a source of electrical current to an anode and a cathode positioned within the container. The anode comprises a base material selected from titanium and niobium. An outer layer of platinum is bonded to the base. The anode comprises a cylindrical shape. The cathode is also connected to the power supply and comprises titanium and has a substantially cylindrical shape. The cathode is positioned concentrically in relation to the anode. The spacing between the cathode and the anode is not greater than a preferred amount. Moreover, the voltage potential between the cathode and the anode is not greater than a preferred amount.

Abstract: A logging tool provides a log of fractional flow characteristics of formations surrounding an earth borehole. The logging tool is suspended in the borehole and resistivity measurements are made at different radial depths of investigation while the logging tool is moved through the borehole to obtain several resistivity logs. Model fractional flow parameters are selected, and a formation conductivity model as a function of the model fractional flow parameters is determined. Several simulated resistivity log values are generated at respective radial depths of investigation from the formation conductivity model. The simulated resistivity log values are compared with values from the resistivity logs of the resistivity measurements to obtain an error indication. The model fractional flow parameters is modified accordingly. Steps are repeated until a predetermined criterion is met, then an output of formation fractional flow characteristics is produced.

Abstract: A method for measuring multiphase flows in a conduit using series of microwave antennae arranged around the circumference of the conduit so as to transmit microwave energy into, or detect propagated microwave energy in the conduit, the method including the steps of: transmitting microwave energy from each antenna in turn while detecting microwave energy at the non-transmitting antenna and integrating the results from all antennae so as to characterize the flow in the conduit. Apparatus for performing the method includes means for exciting each antenna in turn to transmit microwave energy into the pipe and means for detecting microwave energy at the non-transmitting antennae, and means for integrating the results from all transmitters to characterize the flow in the conduit.

Abstract: The disclosure invention is directed to a nuclear magnetic resonance measurement apparatus that can be utilized in a logging device which operates generally centrally in a borehole, and has a generally circumferential region of investigation, but which permits usage of relatively powerful permanent magnets, such as rare-earth magnets, that are not permeable to the RF magnetic field. This is achieved by employing side-by-side spaced apart elongated magnets, and an RF current loop in the region between the magnets. In a disclosed embodiment, the magnets are each in the shape of a segment of a cylinder, and the respective axes of elongation of the magnets are parallel. The magnets have respective casings with electrically conductive surfaces, and the RF current loop includes at least a portion of the conductive surfaces of the magnet casings.

Abstract: Methods and apparatus are provided for determining an indication of a nonlinear property of the formation. A sonic tool is used in a borehole to generate a signal having multiple cycles of a wave of a predetermined frequency. The amplitude of a tube wave resulting from the signal is measured. The measured amplitude is then used to determine an indication of the nonlinearity of the formation according to a relationship which relates the measured amplitude to the amplitude of a second harmonic tube wave which is generated in the borehole by the tube wave of the predetermined frequency due to the nonlinear property of the formation. The indication of nonlinearity may then be utilized to give an indication of the relative consolidation of the formation surrounding the borehole.

Abstract: A method of investigating a formation traversed by a borehole includes, measuring at a plurality of different static borehole pressures the acoustic Stoneley and/or flexural wave velocities of waves propagating through the borehole and formation, and generating an indication of the nonlinearity of the formation by processing the velocity measurements. The velocity measurements are processed either by determining a fractional change in the measured acoustic velocity and dividing that fractional change by the change in borehole pressure to provide frequency dependent acoustoelastic coefficients, or by determining the fractional change in the measured acoustic velocity, and subtracting from the fractional change a component generated by the borehole fluid and a component due to linear aspects of the formation to provide a nonlinear formation component. By processing the velocity measurements at a plurality of frequencies, the nonlinear formation components are used to find nonlinear parameters of the formations.

Abstract: A method for determining the elemental concentrations in an underground formation by irradiating the formation with neutrons, detecting the .gamma. ray spectrum arising from neutron capture by the formation and analyzing the spectrum to determine elemental concentrations. This method avoids the need for activation measurements or natural radiation measurements and which is made possible by modifying the detected yield of iron (Fe) in the spectrum to compensate for the absence of aluminum (Al) and for the absence of potassium (K) when not measured directly. Apparatus for performing this method can comprise a neutron source, such as a broad energy chemical source, e.g. AmBe, or a pulsed accelerator source, a .gamma. ray detector for detecting capture .gamma. rays and means for analyzing the spectra detected by the detector for determining the elemental concentrations in the formation.

Abstract: Characteristics of invasion profiles exhibiting effects of gravity, and particularly their manifestations on resistivity logs of a plurality of different radial depths of investigation, are used to determine formation characteristics, including vertical permeability. One embodiment includes the following steps: suspending a logging tool in the borehole; producing a plurality of resistivity measurements, having respectively different radial depths of investigation, as the logging device is moved through the borehole, to obtain a plurality of resistivity logs; determining the presence of a buoyancy marker in the resistivity logs in a formation bed invaded with filtrate from the drilling mud, and the extent of the buoyancy marker; and determining permeability of the formations as a function of the extent of the buoyancy marker.

Abstract: A logging tool for use in determining the resistivity of an underground formation surrounding a borehole comprises a mandrel with two transmitters spaced apart thereon, each serving to establish a current in the mandrel and in the underground formation. A series of electrodes are spaced along the body between the transmitters and sensors, located at each electrode, measure radial current flow along a path from the mandrel to the underground formation via a respective electrode. Sensors also provide the axial current flowing along the whole mandrel and at positions corresponding to each electrode. A method of determining the formation resistivity includes the steps of measuring the radial currents R.sub.1 R.sub.2 from the mandrel to the formation via each electrode and obtaining the axial currents M.sub.01 M.sub.02 along the mandrel at each electrode due to each transmitter; measuring the total axial current M.sub.

Abstract: The invention concerns a method of and apparatus for measuring the flow rate of a continuous phase in a flowing multiphase fluid. It includes the steps of measuring a velocity of the fluid with a thermal anemometer at a location in the flow and simultaneously measuring the passage of a discontinuous phase at the same location with a local probe system capable of measuring the passage of a discontinuous phase, and then using the measurement of the discontinuous phase to correct the measurement of the continuous phase so as to derive the flow rate thereof.

Abstract: Inelastic scattering gamma ray spectra taken in a borehole are analyzed by a least squares spectral fitting process to determine the relative elemental contributions thereto of chemical elements postulated to be present in unknown earth formations and contributing to the measured spectra from the formations. The relative inelastic yields for silicon, calcium and magnesium are calibrated to provide straightforward estimates of the respective elemental concentrations for those elements and of the volumetric fractions of the elements or associated rock types, such as sandstone, limestone and dolomite, in the formations. The ratio of the relative inelastic yields for magnesium and calcium provides an indication of the degree of dolomitization of a formation. A technique for determining formation iron content from the relative inelastic iron yield in open or cased holes is also disclosed.

Abstract: A two-dimensional array of slot antennas which can provide two-dimensional quantitative dielectric and conductivity images of formations in the region surrounding an earth borehole. The antennas are mounted in a wall-engaging member of a logging device that is moveable through the borehole. Selected ones of the antennas are energized at given times to transmit electromagnetic energy into the formations, the electromagnetic energy being received at other antennas for processing to obtain formation properties.

Abstract: A logging method and apparatus for investigating the geometrical characteristics of a borehole comprises an array of circumferentially spaced apart azimuthal current electrodes (Aaz.sub.i) disposed on a sonde (21), and an annular current electrode (A) longitudinally spaced apart from the array of azimuthal electrodes. In a method of investigating the geometrical characteristics of the borehole, currents (Ic.sub.i) are emitted between the azimuthal electrodes and the annular electrode (A). Monitor electrodes (M, Maz.sub.i) are respectively associated with the current electrodes (A, Aaz.sub.i). The potential differences (Vc.sub.i) between annular monitor electrodes (MAz.sub.i) are detected. In response to the detected potential differences, output signals (Rc.sub.i) are generated indicative of the distances between the sonde and the wall of the borehole in a plurality of directions around the sonde.

Abstract: The first and second moments of an epithermal neutron slowing down time curve are determined and are combined in accordance with a predetermined empirical relationship to derive a raw measurement of the porosity of an earth formation surrounding a borehole. The raw porosity value is then combined with the second moment in accordance with further predetermined empirical relationships to derive a standoff measurement and a standoff-correction factor to be applied to the raw porosity measurement to produce a standoff-corrected porosity measurement. Where the raw porosity value changes appreciably from depth level to depth level, a differential spatial filter is applied to the raw porosity measurement and to the standoff-correction factor to provide a more precise standoff-corrected porosity measurement.

Abstract: A method and apparatus for determining the setting time of a cement slurry. An acoustic shear wave signal is generated and introduced at a first location in the slurry. The signal is monitored at a second location for direct transmission of the shear wave signal. The time of first detection is determined at the second location which is taken as the setting time of the slurry.

Abstract: A slot antenna has a square aperture and two current probes at angles to each other in the aperture. The two current probes are excited simultaneously or separately with different signals. By adjusting the amplitude or phase of the signals in the current probes, the angle of the magnetic moment of the antenna can be adjusted. An array of such antennas in an electromagnetic propagation tool for a well-logging device simultaneously provides better standoff performance by adjusting tile magnetic moment to be parallel to a borehole axis, and better image response by adjusting the magnetic moment to be perpendicular to the formation bed. The array can be excited to function as an endfire and broadside array of an electromagnetic propagation tool.