Abstract: A method and apparatus for measuring a mixture of oil and water in a well borehole is set forth. The measurement is a measurement of mixture dielectric constant obtained by exposing a pair of windows to the mixture of well borehole liquids. Each window is formed in coaxial cable portions having cuts in the respective surrounding ground sheaths thereof wherein the sheaths are positioned so that the windows are adjacent and parallel. The two windows form a gap which may be approximately three times wider than the windows formed in the sheath. A signal generator drives the system at a specified voltage and frequency, and changes in signal coupled between the cables are measured where the changes derive from changes in the dielectric constant of the mixture of oil and water coupled in the circuit.

Abstract: A method for enhancing a plurality of recorded waveforms from sonic logging is disclosed. As a function of depth along a well borehole, a plurality of sonic waveforms is obtained. Adjacent waveforms are registered by time shifting so that common event coincides between adjacent waveforms. Typically this is the arrival of the P, S or S.sub.t wave component. Then, adjacent waveforms are subtracted from one another to provide a difference waveform, and the difference waveforms are then presented. This enhances oblique occurring events. Further, instantaneous waveform characteristics for each of the recorded waveforms are presented to further assist in data interpretation to locate and identify oblique occurring events.

Abstract: A downhole MWD tool for generating pressure pulses in a drilling fluid comprises an elongate body for positioning in a drill collar and a plurality of blades spaced around the body. Each blade is divided into an independent front section and rear section one of the front and rear sections being mounted on a rotatable shaft such that the front and rear sections are angularly displaceable relative to one another between a first position in which the sections are aligned and a second position in which the rear blades obstruct fluid flow between the front sections to generate a pressure pulse. A hydraulic actuator is operable to rotate the shaft, and is powered by the pressure difference in the drilling fluid between an upstream end of the tool and a position downstream of the tool.

Abstract: The transmitter and receiver coils (35,40) in an electromagnetic dipmeter (10) are separated by a finite spacing (L) to remove borehole positional effects. Dip and strike are then determined with the same methods available for zero spacing devices by pulsing the transmitter signal.

Abstract: A method and apparatus for determining the location in space of a formation sample is set forth. This involves a tool which is typically run on a wireline in a well, the tool supporting orthogonal positioned magnetometers and similar orthogonal accelerometers for measuring movement of the tool along the well borehole whereby components of the magnetic field and gravity field are measured to enable determination of the well in space. The tool supports an axially positioned centrally located core cutting apparatus and a laterally projecting plug cutting apparatus; scribe marks formed on the formation samples orient the samples relative to the tool and the tool is located in space from the above mentioned measurements so that the position of formation samples can be determined.

Abstract: A dipmeter has a coil forming a medium frequency field (e.g., five megahertz); the field interacts with the formation to form induced currents in the formations dependent on resistivity. The formation boundaries create a phase shift contrasting with the shift occurring in the formation so that a pair of closely spaced coils on a shoe locates relative transition of a formation boundary. The boundary is located by the several dipmeter arms.

Abstract: A caliper tool mechanism is set forth. In the preferred and illustrated embodiment, a pair of opposing caliper arms are pivotally mounted on a elongate body and are recessed in elongate slots in said body. The caliper arms are retracted to a parallel position. The arms extend parallel to the elongate body and cover an elongate leaf spring. The spring has a fastened lower end affixed to the lower end of the body, and upper ends joined through moveable lengths to said caliper arms.

Abstract: A multiple arm caliper system for operation of a multiple arm caliper tool is set forth. It incorporates an elongate tool body having a motor means therein. The motor means operates a coupling rod connected to a resilient spring loading a piston within a cylinder. Within the cylinder, and extending through a transverse head defining the cylinder, individual push rods for each caliper arm extend. The push rods are forced from the chamber by fluid pressure within the chamber. Each push rod connects through suitable pivot points to an independent bell crank which is pivotally mounted to rotate each arm. Fluid pressure within the chamber is provided by the motor operating through a push rod which couples through a coil spring in the preferred embodiment to the chamber.

Abstract: Formation fluid flows in earth formations (37) opposite a perforated (40) wellbore (15) zone are measured and monitored by injecting radioactive tracers (50) into the perforations (40), blocking the perforations to retain the tracers (50) in the formation (37), monitoring the apparent decay rates (58) of the injected tracers (50), and then determining the rate at which the tracers are being carrier away by fluid movements in the formation (37). From this the flow rate (60) of the fluids in the earth formations (37) adjacent the borehole interval is inferred.

Abstract: In a logging tool which transmits electromagnetic radiation into adjacent formations, and including such tools which operate as low as 20 Khz (typical for induction logs) up to as high as the gigahertz range, an improved antenna system is set forth. The antenna preferably transmits a circular polarized signal so that reflected and refracted return constituents in the receiver signal can be sorted out. For intermediate frequencies, the antenna can be potted in a high dielectric constant material.

Abstract: A method for fluid pressure testing of a formation behind casing is set forth. A formation testing tool is lowered into the well to a specified depth opposite a formation of interest behind a casing. A test probe is extended and a perforation is formed from the test probe into the formation to obtain fluid communication with the formation. Utilizing a storage container in the testing tool, fluid is pumped from the formation into the test tool, or from the test tool into the formation and formation pressures are measured at selected intervals.

Abstract: An induction tool including a coil array having a plurality of transmitter coils and a plurality of receiver coils. Each plurality of coils is symmetrically arranged on an insulated mandrel about a selected point. The induction tool also includes an oscillator circuit that provides an alternating frequency signal to the transmitter coils. A receiver circuit is connected to the receiver coils to measure signals indicative of the voltages induced on these receiver coils to the surface. By varying the spacing between the receiver coils and transmitter coils it is possible to independently vary the vertical and radial measurement capabilities of the tool of the present invention. A dual induction tool having high vertical resolution is also disclosed. The dual induction tool includes a pair of transmitter/receiver coil arrays, each transmitter/receiver coil array having a different transmitter-to-receiver coil spacing and substantially indentical vertical resolution.

Abstract: A stretch corrected wireline depth measuring system is set forth including method and apparatus. It forms a log quality indication which indicates those occasions where the tool velocity is outside acceptable limits. The apparatus utilizes calibrated encoder wheels, preferably a redundant and duplicate pair, to form pulse trains indicative of surface wireline velocity. Additional measurements are made of wireline tension, and magnetic marks on the wireline are observed. All of this data is input to a CPU which determines the raw depth, and adjusts this value with depth corrections. The device calculates wireline stretch as a function of tension and total wireline in the borehole. This enables formation of output data as a function of depth including cable tension, tool speed, depth correction and log quality in the event that tool velocity is outside an acceptable range.

Abstract: A pulse height analyzer for spectrocopy thermal multigate decay well logging systems is disclosed and has an input section comprising a peak time determining circuit locating a peak occurrence. The peak is determined relative to a threshold voltage determining circuit. On peak detection, a timing signal is formed for a control circuit. This operates a sample and hold switch at the output of an amplifier for the input. This switch inputs to an A/D converter driving a buffer. Various handshake signals cooperate with a telemetry system to transfer the peak time A/D valve for pulse height measurement.

Abstract: An acoustin transducer system for a borehole televiewing apparatus is set forth. In the preferred embodiment, a ceramic circular disc is used and is divided by grooves selected thereon into a set of N concentric rings where N is a whole number integer. Each ring has its own associated transmitter and they are fired in a controlled sequence. Each ring operates as a receiver, and they form output signals which are amplified and controlled delay at the respective delay lines, the several output signals are summed. This assures that the illuminated regions of the borehole is in focus and has a greater depth of field. And a method is also described whereby multiple simultaneous electronically formed acoustic beams are utilized in a differential mode to achieve high spatial resolution in time of flight measurements.

Abstract: A fluid flow and simultaneous fluid density measuring device is set forth. The preferred embodiment incorporates a sonde having a lower inlet port, an upper outlet port, a lengthwise tube extending through the sonde and connected with the ports. A packer provides external isolation to direct all fluid flow into the tube. A float within the tube is buoyantly raised primarily as a function of fluid velocity and fluid density, and the position of the float is measured by placing a radioactive source in the float and measuring the count rate at spaced detectors to ascertain float location. Fluid is simultaneously measured by determining the radiation count rate attenuation of the fluid. With other fixed parameters and measurement of the float position and fluid density, the fluid flow rate can be determined. Both method and apparatus are set forth.

Abstract: A coil array which is installed on a MWD drill collar for use in a resistivity logging system. The drill collar is provided with upper and lower coil support rings. These are toroids which support individual coil segments, and are connected by suitable magnetic shorting bars. The coil segments and shorting bars inscribe a specified solid angle or azimuthal extent. By connecting the outputs of the several coils through a combining circuit, the coils on a single coil form can be connected in series additive, or subtractive relationship. Through the use of two such coil forms with aligned coils on each, an azimuthally oriented window is thereby defined. By proper switching multiple azimuthally oriented windows can be made operative so that there is an azimuthal orientation to the current flow pattern relative to the MWD resistivity logging tool.

Abstract: A borehole televiewer system is disclosed which includes a sonde adapted to be suspended in a borehole containing borehole fluids. A variable speed brushless DC motor within the sonde is utilized to drive a rotatable mount at selected speeds in order to maintain a rotational speed in proportion to the linear speed of the sonde through the borehole. A "quick-disconnect" transducer head, including diametrically opposed acoustic transducers, is mounted to the rotatable mount in direct contact with the borehole fluids and is utilized to repetitively transmit energy pulses at the wall of the borehole throughout each rotation. Receiver circuitry is then utilized to determine the amplitude and transit time for each reflected pulse in order to determine parameters of interest for the borehole wall. In a preferred mode of the present invention, the reflected pulses are then utilized to generate a video representation of the borehole wall in addition to providing a graphic plot.

Abstract: A perforating gun assembly is set forth. It incorporates a swivel connected with a cable head assembly and a navigation system for determining the instantaneous angle of the tool with respect to a vertical reference. There are first and second spaced cages formed of sleeves supported on bearing assemblies. The sleeves support free wheeling rollers which engage the casing when the tool is in the slant hole region of the well. There is an eccentric which falls downwardly, i.e., pointing toward gravity, and thereby defines a vertical reference and hence a horizontal reference. This eccentric mounts an elongate tubular housing for the shaped charges. Initially, the angle of firing of the shaped charges is adjusted at the time of installation with respect to the horizon and that in turn is correlated to the formation of interest in the well borehole which is then perforated with perforations which are parallel to the formation bedding plane.

Abstract: High resolution induction logs (28) are obtained through borehole casing (15) by magnetically saturating the casing (15), logging with a tool (10) having different transmitter (35a, 35b)-to-receiver (40) coil spacings, and determining the formation (30) conductivities as a function of the coil spacings, coil frequency, and phase difference between the signals at these spacings. The logging is preferably done at an intermediate frequency which gives good resolution but is little affected by the saturated casing.