Abstract: Apparatus for generation of shear or compressional type vibrations within a borehole wherein oppositely oriented first and second acoustic energy sources are energized to produce output tube waves which, in turn, are equally deflected to propagate energy toward opposite sides of the borehole. Energization of the sources in-phase effects output of compressional wave energy and energization of sources 180.degree. out of phase results in shear wave generation.

Abstract: Apparatus and methods are disclosed in which a radar target can be electronically disguised to appear like another target.The technique is based on the generation of a desired synthetic target signature that is superimposed on the normal radar echo for the simulation platform. The simulation system consists of multiple antennas with tapped delay lines and signal modulators to provide the means of generating the desired target signal that is extended in angle and range. It is possible to utilize very realistic models of the desired target; the necessary information can be collected on a high-resolution measurement range. The general technique works against any pulsed radar in a monostatic geometry. A modified technique for operation against continued wave and bistatic radars is also discussed. The applications of the technique include the testing of missileborne guidance radars against cooperative targets and electronic countermeasures (ECM) applied to a target vehicle to deceive the radar.

Abstract: A method and system are provided for well velocity shooting and vertical seismic profiling utilizing mobile seismic land sources for transmitting powerful seismic energy impulses into the earth. A plurality of nesting pairs of tanks are transported on a single vehicle to a well site where the tanks are unloaded and arranged in a suitable array, for example, in a linear array or uniformly spaced around the mouth of the well. The tanks each have a displaceable end portion serving as a diaphragm placed in contact with the ground near the well. Then the tanks are filled with a noncompressible liquid. The total effective mass of the liquid may be increased by adding density-increasing materials thereto. Air guns are suspended in the tanks submerged in the liquid therein. The air guns are fired in a predetermined manner, abruptly releasing pressurized gas into the liquid contained in the tanks for providing powerful seismic impulses which are transmitted into the ground by the displaceable diaphragms.

Abstract: Method for generating a composite logging data base from two separate historical data bases in a form suitable for further on-site computerized analysis and processing. A generalized system is provided for automatically producing, as a function of a plurality of elected options, an output which is either a merger of logging curves from the two data bases, a replacement of one or more logging curves or portions thereof from one data base with those of a correlative curve or curves from the second data base, or a splice of one or more logging curves from one data base derived over one borehole increment with a curve or curves from the second data base derived over a different borehole increment, with further provision for automated renaming and reordering of curves as they appear in the output as well as compatibility checks between the two data bases thus being combined in terms of logging parameters and borehole increments as a function of the elected option.

Abstract: A magnetohydrodynamic geophone for seismological detection. The geophone is of rigid shock resistant design, including a sealed, rigid generally conically shaped housing which is adapted to be firmly embedded within the ground in bedrock or the like, in or adjacent to an area to be seismologically monitored. The shock resistant housing includes an isolated interior for receiving an MHD sensor which detects the seismological vibration. The sensor includes a generally tubular conduit containing an electrically conductive fluid, preferably mercury or an electrolyte. A very strong magnetic field is set up perpendicularly with respect to the plane occupied by the conduit. An electric field is generated through the Faraday Effect in response to vibrations. Preferably the conduit is of ring shaped configuration, and the conductive fluid is continuously circulated throughout it.

Abstract: A submersible well pump has a system for monitoring the pressure and temperature in the vicinity of the motor. The system includes a downhole assembly in the well that has a transmitter for generating a signal and superimposing the signal onto the power cable. Transducers in the downhole assembly sense physical parameters such as pressure and temperature and provide electrical responses corresponding to the physical parameters. The transducers are connected to a modulator which modulates the signal provided by the transmitter according to the electrical response of the transducers. The modulated carrier signal is converted at the surface into a readout signal proportional to the physical parameters.

Abstract: For use in an acoustic logging tool having a sonde adapted to be lowered in a borehole, an improved acoustic transducer comprising a pyramidal frustrum is disclosed. The preferred embodiment incorporates fifteen sides. Each side mounts a piezoelectric crystal for receiving. Mechanical resonant frequencies of the transducer are outside the receiver band width which is about 25 kHz. The resonant frequencies are above 25 kHz, thereby avoiding primary resonant frequencies within the band width.

Abstract: A method and apparatus for estimating shear wave velocities where such velocities are difficult or impossible to measure because the shear energy transmission is attenuated or its velocity is equal to or less than direct mud velocity or because the shear wave may not propagate at all under certain conditions. The method and apparatus relate to an indirect technique for determining shear modulus by measuring the phase velocity of the Stoneley wave excitation and using it to estimate the shear modulus and the shear velocity. Using at least two receivers, a window is placed over the Stoneley arrival of the wave detected at each receiver and the Fourier transform of each wave is taken. The difference in phase of the Stoneley wave arrivals is determined. The relative shear modulus involving the Lame constants is estimated by a procedure which includes matching two points on Stoneley wave dispersion curves.

Abstract: In accordance with the present invention, progressive changes in amplitude as a function of offset of common gathers can be more easily identified by displaying difference envelopes of "near" and "far" amplitude vs. time traces of each gather, as a function of common groups of centerpoints. A significant--and progressive--change in P-wave reflection coefficient as a function of the angle of incidence (within sections) indicates valuable characteristics, such as hydrocarbon-bearing potential and/or lithology of the reflecting horizon.

Abstract: A radar antenna with a collector of microwave energy incident along the main lobe of its radiation pattern, feeding a processor whose principal channel generates a raw output signal, is provided within the effective area of that collector with one or more ancillary radiation receivers intercepting energy from side lobes encumbered by interfering signals from directional jammers. The output signals of auxiliary channels connected to the ancillary radiation receivers are subtracted in the processor, at an intermediate-frequency level, from the raw output signal of the principal channel to produce a useful signal which is fed back to an adaptive cancellation loop in each of these auxiliary channels.

Abstract: This invention consists of producing a two-dimensional display from exploration seismic data designed to indicate zones of anomalous low velocity in the subsurface. Such zones may be indicative of porosity and the possible occurrence of hydrocarbons. They will be localized in terms of position along the seismic profile and in approximate zone of reflection arrival time. Data used in making the display are derived from both the CDP stacked seismic profile and corresponding velocity analyses used also to stack the data itself. Stacking velocity curves are plotted according to CDP location for each reflector designated by an interpreter to be of interest. These curves are overlain in pairs using calibration calculations and empirical criteria. Calibration helps smooth "noisy" values and compensates for velocity variations resulting from changes in separation or dip of the two reflectors from which the overlain velocity curves derive.

Abstract: An FMCW distance measuring device is disclosed which enables increased accuracy by detecting the nearest return. A portion of the transmitted wave in an FMCW altimeter is mixed with the received signal indicating distance to ground to produce a beat frequency between the transmitted wave and the received wave. The beat frequency is a spectrum of frequencies, the lowest of which indicates the nearest return in a target area. The beat frequency spectrum is coupled for sampling by an analog-to-digital converter and then coupled to an apparatus for performing a Fast Fourier Transform to isolate the nearest return. In an altimeter, the Fast Fourier Transform of the return spectrum enables the FMCW radar to have an accuracy approaching that of pulsed radars without the associated disadvantages.

Abstract: In order to compensate the unwanted echo caused by the movement of a moving radar device, an arrangement is provided between the output of a coherent oscillator and the input of a phase discriminator. This arrangement comprises a signal processing stage containing two series-connected phase regulating circuits, namely phase-locked loops. The output signal of the first phase-locked loop displays a mixed frequency which is formed by the sum of the frequency of the output signal of a signal generator and a displacement frequency modulated by the Doppler frequency of the unwanted echo caused by the movement of the radar device. In the second phase-locked loop the output signal of the first phase-locked loop is mixed with a further signal containing the displacement frequency.

Abstract: An electronic recording device and multiple sensors for measuring various parameters at locations remote from the recording device. The multiple sensors can be joined together to comprise a downhole tool for measuring various parameters within a well bore and transmitting information concerning each parameter to the recording device via a single conductor electrical wireline. The embodiment disclosed within this patent measures the parameters of pressure, temperature, flow rate plus direction, and collar location. A wide variety of sensors can be included within the downhole tool to measure additional parameters as desired. This invention allows the multiple sensors to measure various parameters at any location remote from the recording device and to transmit information concerning each parameter to the recording device on single conductor electrical line as a composite signal.

Abstract: A method for optimizing the acoustic signal-to-noise ratio during a useful maximal-length recording cycle within the time frame of a minimal-length recording episode. To implement the method, during an intermittent-tow seismic operation, the noise level due to cable manipulation during an entire recording episode is monitored. A quiet-window of a desired length is established by adjusting the length of the interval during which the seismic cable is at rest. The initiation of a recording cycle is adjusted relative to the quiet window to take maximum advantage of the quiet period.

Abstract: Acoustic energy is propagated through earth material between an electro-acoustic generator and a receiver which converts the received acoustic energy into electrical signals. A closed loop is formed by a variable gain amplifier system connected between the receiver and the generator. The gain of the amplifier system is increased until sustained oscillations are produced in the closed loop. The frequency of the oscillations is measured as an indication of the acoustic propagation velocity through the earth material. The amplifier gain is measured as an indication of the acoustic attenuation through the earth materials. The method is also applicable to the non-destructive testing of structural materials, such as steel, aluminum and concrete.

Abstract: A feature referenced error correction apparatus utilizing the multiple images of the interstage level image format to compensate for positional displacement errors in the synthetic aperture radar imaging. Error compensation is accomplished through the registration of key features of sub-aperture images and by the generation of an error correction signal in response to the sub-frame registration errors.

Abstract: In a borehole telemetry system for acoustically transmitting data over a pipe suspended in a borehole, the level of noise in the data stream is inherently high due to the environment existing in a drilling operation and to the physical characteristics of a drill string. It has been discovered that certain discrete frequency passbands exist in a drill string which permit transmission of an acoustic signal with a minimum level of attenuation. In addition, it is now known that a fine structure exists within these frequency passbands which presents gaps or voids that attenuate the signal at a much higher rate. These gaps are on the order of 20 Hz.By generating an acoustic signal at a precise frequency spectrum within these passbands and then phase shifting the signal before its transmission, the energy spectrum of the transmitted signal is spread out over a sufficient frequency range to bridge these gaps.

Abstract: In a system for displaying geophysical information on a video screen, data representative of spaced subsurface strata are stored in a computer memory. The data are extracted, plane by plane, and data bytes representative of the planes are stored in pairs in memories in an image processor. The data representative of one plane is displayed and recorded on a medium such as video tape. An image is then formed using a large fraction of the value of the data representative of one plane and a smaller fraction of the data representative of the next plane, and that image is stored. Successive images are formed using decreasing fractional amounts of the data representative of the first plane and increasing fractional amounts of the data in the next plane. Each image is stored and displayed, the display presenting a sequence of images which appear to merge or dissolve smoothly from one to the next. The process is repeated through all stored strata.

Abstract: A radar system operating by means of frequency-modulated pulsed waves comprises an aerial system for directing such waves to at least one target located at a distance D and for receiving the waves reflected from said target, a mixer circuit having a first input for receiving a local signal, a second input for receiving the reflected signal received by the aerial system, and an output for producing information about the distance D, a frequency-modulated (FM) wave generator, a change-over device cooperating with a control circuit for temporarily connecting the FM wave aerial system to the generator, while the first input of the mixer circuit receives a signal derived from the output signal of the FM wave generator by means of a coupler. The control circuit comprises means for connecting the aerial system to the output of the FM wave generator during one of equal fixed time durations selected in a pseudo-random manner within a time interval of a fixed duration.