Abstract: A seismic vibrator system for imparting compressional and shear wave vibrations into the earth has an earth contacting base with a vertical post. A tubular hub is slidably received on the post in a piston/cylinder relationship. Spaced apart horizontal top and bottom plates are secured to the hub. A mass is slidably supported between the plates. Pistons interconnect the hub and the mass. Hydraulic energy is used to reciprocate the mass vertically on the post and horizontally between the plates.

Abstract: This method and system for estimating Earth environmental effects in relation to planetary orbital dynamics provides for integrating seemingly diverse data input sources gathered from historical data, field data, meteorological sensors, satellites, and the like for geophysical, meteorological, archeological and astrophysical purposes to perform comparison, correlation, time and date determinations for historical analysis and future event prediction. Computer systems which are used to collect and store necessary data are linked by the most appropriate transmission means given the location and data transmission characteristics to be networked. A data base module is used to store historical or archival data as well as large input current data.

Abstract: A system for synchronizing a seismic system having multiple subsystems. A control system transmits a message to selected subsystems and an internal subsystem counter is zeroed to a selected epoch. Depending on the message or on an internal instruction code, each subsystem initiates an event or sequence of events synchronized to the selected epoch. The system is based on the relative occurrence of cyclic events and does not depend on the transmission of an absolute time signal. The system is self rectifying, reduces systemic errors, and reduces the data transmission required for system control and operation. The system permits autonomous, asynchronous operation by a subsystem without continuous control by a central controller as a function of time, and can interactively respond to events without intervention from the central controller.

Abstract: An interpretation workstation based apparatus having an "Auto Fault" software stored therein automatically identifies a plurality of fault cuts in each of a plurality of horizons in a seismic data volume in response to a plurality of predetermined "horizon time structures".

Abstract: A method and apparatus for detecting underground liquids is disclosed in which the electrical potential generated by a seismic shock is detected and measured with respect to a base point insulated from the earth.

Abstract: An improved bottom cable for a seismic marine data acquisition system 10. The bottom cable 30 includes a cable section 30b having a bus 48. The cable, along with the cable section and bus, are used to electrically connect a master control unit 40 to first and second modules 32b and 32c, respectively. The bus 48 includes first and second switches 48b and 48c, respectively, located near opposite ends of the bus. In this way, if a leak R1 occurs in the bus, the first and second switches can be opened, thereby electrically isolating the bus and stopping the leak.

Abstract: Method and apparatus are provided for a new type of geophysical prospecting. The method applies an electric field to a fluid-containing porous subsurface formation to create a fluid pulse from changes in the polarization of pore fluid dipoles. The fluid pulse propagates in the subsurface as a seismic wave that may be detected by an appropriate array of seismic detectors. The apparatus is a pulsed DC or AC source for generating an applied electric field and a seismic detector.

Abstract: An unconstrained transformation filter operator that is efficient in terms of computer resources and that improves circularly symmetric migrated impulse response for steep dips. The filter operator combines selected desirable attributes of the more efficient McClellan transformation filter with selected desirable attributes of the more accurate Laplacian transformation filter. The novel filter operator is not constrained along the k.sub.x and k.sub.y spatial axes by the requirement that it equal cos (k). The transformation filter is averaged over all azimuths to improve its accuracy of response.

Abstract: An acoustic wave transducer useful in sonic logging while drilling a borehole through an adjacent earth formation includes an array of transducer elements mounted circumferentially around a drill collar. The elements are bonded in an elastomer ring that is received in an external groove in the collar and are protected by a shield having windows. The elements are electrically connected in parallel so that when excited by an electrical pulse, the elements generate a monopole acoustic wave that propagates out into the formation. When used as a receiver, the electrically connected array of elements detect averaged acoustic waves from the formation around the circumference of the drill collar and have minimum sensitivity to acoustic multipole waves traveling through the drill collar.

Abstract: An apparatus for measuring in situ stresses surrounding an active earthquake fault and forecasting shallow earthquakes includes a network of monitoring stations, each operating a respective borehole assembly for measuring in situ lateral stresses. The monitoring stations are arrayed along a recognized fault plane and arranged to straddle the fault plane, so that lateral stress readings may be obtained throughout the ground media surrounding the fault zone. All of the monitoring stations communicate with a central data-gathering facility, so that real-time analysis of changes in lateral stress orientation and magnitude surrounding the fault zone may be undertaken, and the results used to forecast forthcoming seismic events. Each borehole probe assembly includes a trio of single fracture expansion probes operated periodically, reiteratively, and automatically to expand against the borehole wall and determine the principal maximum and minimum lateral stress vectors in the underground media.

Abstract: An apparatus for outputting images and any associated audio stored on a photo compact disc includes a compact disc reader and a control device. The compact disc reader is adapted to have at least two heads which are able to read multiple video and audio tracks on the photo compact discs. The reader has a first video and audio output representative of one image and any associated audio stored of the photo compact disc and has a second video and audio output representative of another image and any associated audio stored on the photo compact disc. The control device has display video and audio outputs and an first/second switch. The first/second switch is coupled between the first and second video and audio outputs and the display video and audio outputs.

Abstract: A method is provided for simulating a linear solution gas curve for the determination of the gas-oil ratio for a crude oil well at any pressure using only surface measurements of the well's annular gas rate, a determination of the flowing bottom hole pressure, and knowledge of the bubble-point pressure. From the resulting curve, relationships can be formulated for determining the total produced gas rate. In an alternate embodiment, knowing the total gas rate for a crude oil well, a solution gas curve is simulated and the above relationships can be applied in reverse manner to predict several well characteristics, including either of the crude oil bubble-point pressure, the flowing bottom hole pressure, or the annular gas rate.

Abstract: A method for the synchronization of systems for seismic surveys, wherein the systems are composed of subsystems and may be land-based or marine, consists in the survey system being supplied with an absolute time standard and in a time code based on the absolute time standard being generated in the survey system. There is further provided at least one programmable event generator in the survey system and this is synchronized with the absolute time standard. The time for a specific event is predetermined on the basis of given parameters and supplied with the time code which corresponds to this time. The time for a determined event is then supplied to the subsystems which are also provided with the absolute time standard. The event can thereby be executed in one or more of the subsystems on the basis of the supplied absolute time standard and a synchronization is obtained with the desired accuracy.

Abstract: A multivariate stochastic simulation application that involves the mapping of a primary variable from a combination for sparse primary data and more densely sampled secondary data. The method is applicable when the relationship between the simulated primary variable and one or more secondary variables is non-linear. The method employs a Bayesian updating rule to build a local posterior distribution for the primary variable at each simulated location. The posterior distribution is the product of a Gaussian kernel function obtained by simple kriging of the primary variable and a secondary probability function obtained directly from a scatter diagram between primary and secondary variables.

Abstract: A method and apparatus for estimating the earth's resistance (conductivity) as a function of depth using electroseismic prospecting (ESP) or inverse ESP techniques. Resistance is determined by the frequency-dependent attenuation of reflected EM signals which are produced by application of seismic signals to the earth. A seismic wave is generated by conventional means into the earth, and EM waves are generated back to the surface by different reflectors at different depth levels. This propagation attenuates the high frequencies preferentially. EM waves generated at lower depths are further attenuated relative to those waves generated at more shallow depths. The method and apparatus determines the difference in spectral content between the reflected signals from different horizons based on their relative attenuation and uses this difference as a direct measure of the conductivity between the horizons.

Abstract: An apparatus and a method are provided for measuring the caliper of a borehole, and the standoff of a drilling tool from the walls of a borehole during a drilling operation. The apparatus includes three or more sensors, such as acoustic transducers arranged circumferentially around a downhole tool or drill collar. The transducers transmit ultrasonic signals to the borehole wall through the drilling fluid surrounding the drillstring and receive reflected signals back from the wall. Travel times for these signals are used to calculate standoff data for each transducer. The standoff measurements may be used to calculate the caliper of the borehole, the eccentricity of the tool in the borehole, and the angle of eccentricity with respect to the transducer position. The eccentricity and angle computations may be used to detect unusual movements of the drillstring in the borehole, such as sticking, banging, and whirling.

Abstract: Acoustic energy is used to detect and identify objects buried in soil by imaging acoustic energy reflected from the soil and buried objects. Acoustic energy is injected into soil at an oblique angle relative to the surface of the soil, reflected and received. Signals representative of the reflected energy are processed to generate image signals used to generate images representative of the reflected energy. Objects buried within the soil are identified by viewing the images. In one embodiment, obliquely oriented acoustic energy signals are carried from a source to a soil sample by a first duct and reflections of that energy are carried to a receiver within an adjacent second duct. The ducts acoustically isolate the source from the receiver. A beveled end of the first duct and the second duct are supported above the soil sample for noncontact operations. In another embodiment, an acoustic energy source is obliquely supported upon and forced into engagement with soil in a reservoir.

Abstract: A remote seismic sensing system is provided which operates as a bipolarized, differential mode, LDI (laser differential interferometry) system to detect electrical signals produced at a remote location. In preferred embodiments, the system is used in seismic surveying to detect array signals. An amplified array signal (the electrical signal is coupled to an array retroreflector apparatus (target). The array signal is obtained from an array of seismic detectors, e.g., geophones or hydrophones. The amplified array signal increases the velocity of a Doppler shifting optical component on the target. The target converts a defused sensing beam into two polarized return sensing signals, both of the return sensing signals having been Doppler shifted by the target to contain frequency components that represent motions, e.g., ground motions and wind motions, that are common to both signals and to contain a difference signal which represents the array signal.

Abstract: A remote sensing system is provided which operates as a bipolarized, differential mode, LDI (laser differential interferometry) system to detect an electrical signal produced at a remote location. The system is adapted to reduce the effects of turbulence induced frequency fluctuations by using an array retroreflector apparatus which converts a single sensing beam into a single return beam having two, overlapping, transversely polarized sensing signals; thus, turbulence induced noise will be common mode to both return signals and cancel at the receiver.In preferred embodiments, the system is used to remotely detect an amplified array signal from a plurality of seismic detectors (e.g., geophones or hydrophones) connected to form an array at the remote location. The target is coupled to common motions at the selected location and the amplified array signal is coupled to an optical component within the target.

Abstract: An adaptive, or neural, network and a method of operating the same is disclosed which is particularly adapted for performing first break analysis for seismic shot records. The adaptive network is first trained according to the generalized delta rule. The disclosed training method includes selection of the seismic trace with the highest error, where the backpropagation is performed according to the error of this worst trace. The learning and momentum factors in the generalized delta rule are adjusted according to the value of the worst error, so that the learning and momentum factors increase as the error decreases. The training method further includes detection of slow convergence regions, and methods for escaping such regions including restoration of previously trimmed dormant links, renormalization of the weighting factor values, and the addition of new layers to the network. The network, after the addition of a new layer, includes links between nodes which skip the hidden layer.

Abstract: Methods and apparatus are provided for remotely sensing motions of the earth from the Doppler shift of reflected electromagnetic waves. The apparatus is based on a heterodyne continuous wave or pulsed laser system. The airborne laser system described herein is intended to remotely sense seismic motion. Motion of the earth's surface, when coupled to a reflector, causes a continuously shifting frequency (Doppler) of the reflected sensing laser beam, the Doppler frequency being proportional to the particle velocity of the ground. The method uses electromagnetic waves reflected from reflectors, some of which are coupled to the earth's surface. Similarly, "inertial" reflective surfaces (i.e., vibrationally isolated from any earth motions) are also located at the surface of the earth and employed by the apparatus and methods of the present invention. Both an inertial reflector and an earth-coupled reflector are positioned at each location for which seismic signals are desired.

Abstract: An in situ method is disclosed for determining the structural integrity, set time and locations of anomalies or voids within a material as the material is being cured. Surface waves are transmitted and received a known distance along the surface of the material so that a substantially constant surface wave velocity can be calculated by dividing the known distance by the time it takes for the surface waves to travel the known distance. Surface wave velocity remains substantially constant for all wavelength measurements which do not exceed the thickness of the material. Structural integrity of the material, set time of the curing material and the detection of voids within the material can be determined from the substantially constant surface wave velocity. Structural integrity is determined as being proportional to the substantially constant surface wave velocity.

Abstract: Methods and apparatus are provided for sensing motions of the earth caused by seismic waves from the doppler shift of reflected electromagnetic waves. The apparatus is based on a heterodyne continuous wave laser system.

Abstract: A method of electroseismic prospecting is disclosed for detecting either the presence of two immiscible fluids present in a porous subterranean formation or the presence of a high-permeability rock formation including a substantially aqueous phase therein. A seismic impact produces an acoustical wavefront that results in an enhanced electromagnetic signal when it encounters either types of the above-described formations. This resulting enhanced electromagnetic signal is detectable as an indication of a likely hydrocarbon deposit, thereby giving additional data information with conventional seismic data to the geophysical prospector.

Abstract: A computer-integrated survey system which is useful in the location of underground obstacles, such as rocks, concrete, steel and ice is disclosed. Specifically, the detection system of the present invention is operated by a microcomputer, having a series of sensors, which integrate position-determining systems, time, sub-surface radar, sonar, seismograph, laser equipment and earth-resistivity functions to accomplish its stated purpose. The system is specially designed in a compact fashion so that it may easily be hand-held, if so desired. Simultaneous with the detection and measurement of underground obstacles, in a preferred embodiment of the present invention, a permanent record of all information may be constructed for subsequent review and print-out.

Abstract: The method of geophysical prospecting of polymineral ore bodies including registering pulsed electromagnetic radiation generated by the ore bodies under the action of elastic waves excited in the rock block. The radiation is registered as pulse bursts, each burst corresponding to one ore body. The shape of a pulse corresponding to the ore body under investigation is compared with the shapes of pulses corresponding to ore bodies of the known mineral compositions, and one similar pulse is selected from these pulses. Then a pulse from the burst corresponding to the ore body under investigation is subjected to the Fourier transformation to obtain the pulse height-frequency spectrum of this pulse, which is compared with the pulse height-frequency spectrum of the selected pulse, and when at least two frequencies of the maximums of the amplitudes of these respective spectra coincide, there is established correspondence between the mineral compositions of the known ore body and of the ore body under investigation.

Abstract: A seismic geophysical prospecting method and apparatus is described involving the sequential shooting of lump explosive charges spaced apart in a borehole so as to produce seismic wave reinforcement in a given direction. Fast acting electronic switch means control the detonation of each charge responsive to the advance of the seismic waves front substantially independent of formation pressure wave velocity.

Abstract: A method for geophysical prospecting of complex orebodies, wherein elastic waves are excited at least two times in the rock mass containing orebodies and the radio-frequency electromagnetic pulses produced by said orebodies are recorded during each excitation to pinpoint the arrival time of the first and last pulses in each pulse train (1,2,3,4,5,6), then the difference is found between the maximum arrival time of the last pulse and the minimum arrival time of the first pulse in the pulse trains (1,3,5 and 2,4,6) representing one orebody, said differences being the basis for determination of the thickness of each orebody.

Abstract: An assembly for use in seismic surveys of the sea bed is towed behind a vessel and comprises groups of seismic signal transmitters which are towed through the water, being suspended from float buoys which are combined to form one body which may be formed as a sleeve having limited flexibility. The body is formed with a head member shaped for reducing resistance to the water, and connected to a coupling point for a tow wire to the vessel, which point lies forward of the head member and at the same depth as the transmitters.

Abstract: An area of a seam is defined and a series of shot locations and detectors are arranged along one side of the area to determine reflected signals. Transmitted signals are also received from a line of shot locations on the other side of the area. The signals received are processed according to an adaptive lag-summing technique to give a map showing the geological faults in the seam.

Abstract: The disclosed invention is a method of seismic exploration using non-impulsive vibratory sources activated by stationary, Gaussian codes in urban areas. The method adds a distortion-free quality to the full-waveform seismic records.

Abstract: In the hydraulic fracturing of deep geologic formations for the production of fluid hydrocarbons, and where vertical fractures are formed, a method is described, using seismic geophysical techniques, for determining the azimuth and length of the fractures. This is accomplished by injecting into the formation through the fracture a selected fluid, or producing the fluid hydrocarbons from the formation into the fracture, until the formation, over a selected distance from the walls of the fracture, has a different gas saturation from the condition in the formation farther from the fracture. This condition is mapped by seismic methods.

Abstract: The invention includes a method and apparatus for detecting geophysical phenomena by the use of a synthetic pulse radar. A radar transmitter generates a plurality of component signals of different frequencies which approximate at least a portion of the Fourier transform of a radar short pulse. These component signals are transmitted simultaneously for modulation by the geophysical phenomena, and the modulated component signals are substantially simultaneously received in a receiver. The receiver divides the component signals, and as to each determines representative parameters. The invention also includes a heterodyne receiver which operates with a fixed IF frequency and incorporates a single frequency quadrature system.

Abstract: A method of seismic prospecting is disclosed in which the seismic source is excited in such a manner as to maximize the use of the energy generated by the seismic source. In certain cases it may be desirable to convert the received seismic signals to their frequency domain counterparts before performing subsequent processing. Such conversion may be performed using the discrete Fourier transform with the result that transformed values are obtained only at certain discrete frequencies. It may further be desirable that processing be performed only at subsets of the total set of discrete frequencies with the values at the remaining frequencies being discarded. In the practice of the present invention, source energy is generated only at those discrete frequencies at which subsequent processing is to be performed. As a result there is substantially no source energy in the transform values at the frequencies which are discarded.

Abstract: A method of fracturing a deep borehole to form a vertical fracture, and of determining the azimuth of the resulting fracture, comprising pumping a pressurized fracture fluid into said well through a pipe from the surface, to provide a bottom hole pressure P which is less than the normal fracturing press (NFP), and generating a series of sharp pressure pulses (SPP) of selected magnitude, such that when added to the pressure P, provide pressure peaks greater than the NFP. By providing arrays of seismic sensors at the surface and determining the direction of propagation of the seismic waves generated by the SPP, the azimuth of the fracture can be determined.

Abstract: Faults in a mineral seam are located by an in-seam seismic technique which involves locating shots and detectors in the seam and firing the shots sequentially. The detectors pick up the reflections of the shots from faults and a common reflection point is determined by analyzing the seismic traces from the detectors.

Abstract: The present invention relates to testing--at a second recording truck--a positional reference code (generated by a first recording truck); the reference code (associated with next-in-time positions of a source-detector array operatively connected to the second truck) is interrogated using a microcomputer system of a ground positional controller housed in the second truck. Result: coordination of operations (between trucks) is assured.

Abstract: Faults in an underground coal seam are located by firing a shot at one point in the seam and detecting the seismic reflections in an array of geophones. Signals from the geophones are recompressed and analyzed according to an exponential formula to give a holograph of the seam and to predict the fault pattern.

Abstract: Methods of detecting the presence and extent of hydrocarbon accumulations in subterranean formations are provided comprising introducing a first gas into the formation having the property of being substantially unreactive with the formation and with water contained therein but forming a combustible mixture with hydrocarbons and introducing a second gas into the formation having the property of being substantially unreactive with the formation and water but being explosively reactive with the first gas when mixed therewith in the presence of hydrocarbons. The second gas is mixed with the first gas in the formation and when in the presence of hydrocarbons the mixture explodes thereby generating seismic waves which travel through the earth to the surface thereof. The seismic waves are detected on the surface to thereby determine the presence and extent of the hydrocarbon accumulations in the subterranean formation.

Abstract: In the process of recovering minerals, such as hydrocarbons from shallow tar sands, and the like, one method is to create a shallow horizontal fracture within the tar sand. The size and shape of the perimeter is determined, and one or more secondary boreholes are drilled to the formation inside of the perimeter of the fracture. Pressurized air is injected into the fracture and the hydrocarbons are ignited. After a selected period of burning is carried out, the radius to the burn front, surrounding the recovery area, from which the hydrocarbons have been removed, is determined by placing a source of seismic waves at a selected point over the fracture, and a long array of seismic sensors colinear with the source.The source is energized for different conditions of pressurization in the formation and fracture. The reflected seismic waves are converted to electrical signals, which are compared for all sensors.

Abstract: A seismic method for mapping horizontal fractures in the earth resulting from the application of fluid pressure, at a selected point, at a selected depth, in the earth, comprising the steps of creating a seismic wave in the earth over the expected position of the fracture, and detecting the seismic waves reflected upwardly at a reflecting interface, at or near the fracture, at each of a plurality of seismic sensors, in at least one radial array. The received signals are recorded for each of two conditions: a first case, when the fracture is pressurized, and filled with fluid, and the roof of the fracture is separated from the base of the fracture; and a second case when the fracture is depressurized, and the roof of the fracture rests on the base. Some sensors will show a different character of reflection signal in the two cases. For these sensors the points of reflection are within the outer perimeter of the fracture.

Abstract: The central station of a radio-connected seismic surveying system uses a tethered blimp carrying an antenna and an electronics package including a dc voltage/rf decoupler, a variable dc controlled preamplifier, a P-I-N diode switch for changing the antenna from receive to transmit operation, a transmitter and modulator and a battery. An rf coaxial cable to ground provides means for controlling the preamplifier gain and for switching the central station to the transmit mode by using appropriate dc signals. In the receive mode, the cable carries detected field unit seismic signals, which are detected by the blimp-carried antenna and preamplified by the blimp preamplifier, to the ground for suitable recording and further processing in the ground portion of the central station. An audio channel can also be modulated onto the transmit carrier of approximately 70 MHz to provide voice communications via the blimp electronics, if desired.

Abstract: A method of locating near-surface underground chambers, rooms, caves, pits, tubes, faults in surface rocks, and the like, using acoustic techniques is disclosed. For mapping large areas, a survey grid for transmitter transducer placement first is laid out over the area of interest.A transmitting transducer is coupled to the bedrock at one of the grid sites, and acoustic waves are generated in the earth by operation thereof. Portable acoustic receiving means, including a receiving transducer, are used to detect acoustic waves from the transmitter at a plurality of receiving sites surrounding the transmitting station. Transmitted acoustic waves from the transmitting site received by the receiving transducer are converted to electrical signals by the receiving transducer and recorded for subsequent use. Following operation of the receiving means at each receiving site surrounding the transmitter transducer, the received signals are compared to determine any differences in their magnitudes.

Abstract: Methods and apparatus are described for generating and transmitting signals in accordance with a sequence which defines the time relationship of the signals. Each signal has a band width covering several octaves and may be a pulse. During a transmission interval the repetition frequencies of the signals monotonically sweep in a coherent relationship over bands restricted to an octave such that the spectrum of the sequence has substantially constant energy over a frequency range much larger than an octave. The autocorrelation function of the sequence is characterized by an absence of side lobes which would indicate false targets or produce a high noise level upon processing of the signals in an echolocation system, such as a geophysical exploration system in which the seismograms are constructed by cross correlation of the signals which are received from the geological reflection surfaces with a stored replica of the transmitted signals.

Abstract: A buoy system for obtaining oceanic data from a predetermined depth to the urface includes an instrument vehicle programmed to cycle between predetermined positive and negative buoyancy conditions. A flexible tether having a degree of stiffness and a positive buoyancy factor distributed along its length is connected between a subsurface buoy and the vehicle so as to provide an increasing upward force on the negatively buoyant vehicle as it sinks toward a hovering depth at which the upward force of the buoyant tether balances the negative buoyancy of the vehicle.

Abstract: A method of seismic prospecting using electromagnetic grounded antennas to detect electromagnetic waves that are produced from acoustic waves in the earth's formation. Seismic waves reflected by a formation in the earth are converted into electromagnetic waves in the vicinity of the antenna according to the streaming potential theory. The antenna has two electrodes which detect the horizontal component of the electromagnetic waves, thus providing additional seismic information that is not readily available using standard geophones. Antennas are also not subject to coupling problems and thus provide more accurate information than traditional geophones. For example, using multicomponent detection, all three components of the seismic pressure gradient can be detected.

Abstract: A method and apparatus are disclosed for detecting seismic waves and electromagnetic waves at the same location in making geophysical measurements. A seismic wave is generated at a first location and the seismic wave and electromagnetic waves generated by said seismic wave are detected at a spaced-apart second location. The seismic wave may be detected by a single apparatus that also detects the magnetic field. Alternatively, the seismic wave may be detected by two spaced-apart apparatus that also measures the magnetic field at the two spaced-apart locations as well as measuring the electric field between the two apparatus.