Abstract: Implementations of a partitioned database system and a method of using a database system are disclosed. One system implementation includes storage facilities. Each storage facility includes data from database table rows. The database table rows in each storage facility that correspond to a specific database table are logically ordered according to a row identifier (row ID). The row ID includes a first value that is based on one or more columns of the table. The row ID also includes a second value that is based on one or more columns of the table, which may be different from or the same as those on which the first value is based. The first value of the row ID is predominate in determining the order of the rows in the storage facilities. The second value determines the order of those rows with identical first values.

Abstract: An apparatus and method is disclosed for induction logging of electrical properties of earth formations that operates at low frequencies while remaining resistant to skin effect and maintaining mutual balancing. The apparatus includes a plurality of transmitter coils that are at a plurality of distances from a measure point located at an end of the apparatus, and a receiver coil array coupled to receive induced voltages resulting from currents induced in the earth formations by one or more transmitters of the plurality of transmitter coils, wherein the common measure point is located within the receiver coil array, and wherein one or more of the plurality of distances from the measure point are determined according to a function of one or more frequencies associated with one or more transmitters of the plurality of transmitters. According to an embodiment, the function includes determining the distance that is inversely proportional to a square root of the frequency associated with the one or transmitter.

Abstract: A directional induction logging tool is provided for measurement while drilling. This tool is preferably placed in a side pocket of a drill collar, and it comprises transmitter and receiver coils and an electromagnetic reflector. The reflector, which may be a layer of highly conductive material placed between the coils and the body of the drill collar, serves to focus the electromagnetic fields generated and sensed by the tool in the direction away from the reflector, thus providing a directional response to formation conductivity with a relatively high depth of investigation. In preferred embodiments of the invention, magnetically permeable cores are placed within the coils to concentrate the magnetic fields that pass through them. Circuitry is described for balancing the mutual inductive coupling of the coils by injecting a direct current signal through one or more of the coils, which alters the magnetic permeability of the core material.

Abstract: An inductive collar locator tool is provided that provides improved sensitivity and precision in locating collars and other discontinuities in a casing string. In a preferred embodiment, the collar locator includes a transmitter coil that produces an oscillating magnetic field, which couples to the casing string proximate the tool. The tool also includes a pair of spaced receiver coils connected to signal processing circuitry which provides an output signal representing the difference in the phase of the magnetic field detected by the receiver coils. The phase difference is relatively constant when the tool is in plain casing pipe, but it changes rapidly when the tool passes through pipe that includes discontinuities, such as joints or collars. The collar locator tool may include an on-board oscillator and digital signaling capabilities. The collar locator is preferably enclosed in a titanium pressure housing that is adapted for through-tubing operations.

Abstract: A retrievable resistivity logging system is provided for obtaining directional resistivity information while drilling (e.g., in an MWD system). The information obtained by this system can be used to determine the proximity of resistivity discontinuities and for use in steering the progress of the wellbore in the presence of geological boundaries of interest. In preferred embodiments, the logging system comprises passive transmitter and receiver electrodes built into subs that are incorporated into the drillstring, and a retrievable instrument cartridge that comprises spring loaded contacts that engage contact surfaces in the subs to connect the electrodes to the cartridge. In some embodiments, the cartridge comprises toroidal transformers coaxial to the cartridge for generating the survey current and for detecting the received current from the receive electrode.

Abstract: A system for generating two or more frequencies for a borehole heterodyne measurement system for use in measuring electromagnetic propagation properties of rock is disclosed. A precision clock oscillator supplies a binary counter with clock signals. The output of the binary counter is supplied as address information to one or more pre-programmed ROMs. The ROMs are used to store multiple cycles of desired output signals. Output signals from the counter may also be supplied as square wave local oscillator signals in the system.

Abstract: An improved system for measuring dielectric properties of fluids in an oil well, utilizing the well casing as a waveguide for certain electromagnetic signals. A production logging tool in accordance with the invention includes a cylindrical mandrel sheathed by a housing. Transmitting and receiving coils are contained in annular grooves defined in the mandrel. In operation, the tool is suspended by a wireline logging cable within the casing of a producing well. The transmitting coils generate magnetic fields and azimuthal electric fields, which induce voltages in the receiving coils. These voltages are affected by the dielectric properties of fluids in the casing, and the voltages may be interpreted to determine dielectric properties such as water resistivity, dielectric permittivity, water hold-up, water cut, and water salinity.

Abstract: The present disclosure is directed to a method of obtaining a different radial depth of investigation from an induction log. A typical induction log is moved along a well borehole to obtain two logs one being at a medium depth and the other being at a larger depth of investigation. By utilization of data from the two curves, the present disclosure enables determination of a log at some other depth i.e. a different radius of investigation which is between the medium and deep depths of investigation.

Abstract: In an MWD system, a mandrel for connection to the drill bit is set forth which supports shallow, intermediate and deep measuring resistivity systems. By transmitting upwardly and downwardly in alternate fashion, and receiving the transmitted signal at pairs of receiver coils, transmitted signal phase shift and attenuation are measured. A method of measuring is set forth which includes making resistivity measurements close to the drill bit at increasing ranges from the borehole so that formation resistivity prior to fluid invasion is obtained. Measurements are thus provided of formation resistivity before, during and after fluid invasion. The method also accommodates formations which have a relative dip angle with respect to the well borehole.

Abstract: A method and apparatus for determining the percentage of gas by volume in a well producing mixed phase fluids and flowing up the cased well. A low energy gamma ray source irradiates the flowing fluid and counts are measured by a detector crystal. A metal casing shields the surrounding formations from the gamma radiation so that the detector response is determined primarily by the mixed phase fluids flowing in the well. Calibration enables the determination of gas volume percentage for a specific diameter casing.

Abstract: An apparatus for induction logging is disclosed. By transmitting a sequence of pulses at many frequencies, the formation invaded zone diameter can be distinguished as a result of changes in resistivity. As higher frequencies are swept, dielectric constant varies with frequency and this variation is evident in chart form. An apparatus for controlled antenna field formation is also disclosed including a sonde construction involving antenna coils on the sonde with dielectric discs to reduce parasitic radiation.

Abstract: An improved induction well logging processing technique for determining conductivity measurements of subsurface earth strata. An in-phase conductivity signal and a quadrature conductivity signal are obtained from a downhole induction logging tool. The in-phase conductivity signal and the cubed square root of the in-phase conductivity signal are filtered by a first filter and a second filter, respectively. The outputs of the filters may be summed to provide a first conductivity signal having reduced environmental effects and indicating the conductivity of the earth formation under test. Additionally, the in-phase conductivity signal and the quadrature signal may be filtered and summed to provide a second conductivity signal. A weighted average of the first and second conductivity signals may be used as an indication of the earth formation conductivity.

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: 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 system for measuring the complex dielectric constant of a core sample is set forth. It incorporates a circular wave guide having a central axial transmitter coil. Equally spaced axial receiver coils are placed on both sides of the transmitter coil. The opposite polarity receiver signals are connected to an adder circuit to provide an output signal representing only the difference in the two received signals. By placing a standard such as air between the transmitter coil and one receiver coil, or core sample positioned between the transmitter coil and the other receiver coil provides a system for obtaining an output indicative of complex dielectric constant. Optionally, the system is operated in an oven to provide an elevated temperature, and can also be pressurized with a compressed fluid.

Abstract: A digital induction resistivity logging tool is disclosed for digitally measuring both the in-phase (R) and quadrature (X) phase components in a receiver signal generated in response to transmitter induced currents flowing in the earth's sub-surface formations. The digital indication tool includes a digital sinewave generator for generating a highly phase stable, low distortion transmitter signal, the frequency of which is selectable from among a plurality of transmitter frequencies. One phase sensitive detector is used alternately to detect both the R and the X phase component signals. Automatic phase compensation is included to periodically compensate for both static and dynamic temperature dependent phase shift errors due to circuits of the tool involved in the component measurements. A floating point analog-to-digital converter capable of handling the wide dynamic range in the detected phase component signals is provided to convert the phase detector output into digital signals.

Abstract: A connector for a ceramic hybrid circuit to operatively associate the circuit to a cartridge chassis within a well-logging tool in a well borehole, has a plurality of spring-loaded electrically conductive contact pins which support the ceramic hybrid circuit so that it may sufficiently and freely move, without damage thereto, as a result of thermal expansion and contraction caused by temperature changes in the borehole and the ceramic hybrid circuit is sufficiently restrained to prevent damage thereto from shock and vibration forces exerted upon the well-logging tool.

Abstract: A digital induction resistivity logging system is disclosed for digitally measuring phase components in a receiver signal generated in response to eddy currents flowing in the earth's sub-surface formations. The induction logging system includes a central processing unit (CPU) located at the surface for receiving digital signals from a digital induction logging tool located downhole, and for analyzing the received data. The CPU supplies command and control signals to the induction logging tool to specify operating modes and parameters for obtaining the digital signals. The system further includes a digital telemetry system associated with a wireline cable for transmitting and receiving data between the induction tool and the CPU. The digital induction tool includes a digital sinewave generator for generating a highly phase stable, low distortion transmitter signal whose frequency is selectable from at least two of transmitter frequencies.

Abstract: A digital induction resistivity logging tool is disclosed for digitally measuring both the in-phase (R) and quadrature (X) phase components in a receiver signal generated in response to induce eddy currents flowing in the earth's sub-surface formations. The digital induction tool includes a digital sinewave generator for generating a highly phase stable, low distortion transmitter signal to a transmitter coil. One phase sensitive detector is used to detect both the R and the X phase component signals in the receiver signal. Automatic phase compensation is included to compensate for both static phase shift errors and periodically to compensate for temperature dependent phase shift errors, both static and temperature errors being introduced by circuits of the tool.

Abstract: A digital induction resistivity logging system is disclosed for digitally measuring in one phase sensitive detector both the in-phase (R) and quadrature (X) phase components in a receiver signal generated in response to eddy currents flowing in the earth's sub-surface formations. The induction logging system includes a central processing unit (CPU) located at the surface for receiving digital signals from a digital induction logging tool located downhole, and for processing the received data. The digital induction tool includes a digital sinewave generator for generating a highly phase stable, low distortion transmitter signal the frequency of which is selectable from among at least two transmitter frequencies. Automatic phase compensation is included to dynamically compensate for both static and temperature dependent phase shift errors introduced by circuits of the tool involved in the component measurements.