Abstract: Systems and methods related to allocation of multiplexing signatures to wireless data acquisition modules in a seismic array with real time wireless read out. The allocation may include selecting an index value offset from an adjacent index value to form serial data transfer paths wherein reuse of multiplexing signatures are spaced as far apart as possible in serial data path. In an embodiment the allocation of multiplexing signatures may be adaptive wherein a module may scan for the presence of signals utilizing a plurality of multiplexing signatures and in turn employ a multiplexing sequence that avoids any detected noise that could lead to interference. The detected noise may be attributable to sources within the survey area or from ambient noise present in the area.

Abstract: A battery system with at least one module includes a plurality of battery cells. A cell voltage detecting circuit is associated with each battery cell of the plurality of battery cells. The cell voltage detecting circuits of the at least one module are connected to a multiplexer. An output of the multiplexer is connected to a communication bus via an analog-digital converter. The communication bus is connected to an evaluating unit. The multiplexer is additionally connected to at least one auxiliary voltage source that is known to the evaluating unit. In a method for monitoring a battery system with at least one module including a plurality of battery cells, a voltage of each of the battery cells is detected and fed to an evaluating unit via a cell voltage detecting unit. An output signal of the cell voltage detecting unit is tested for plausibility.

Abstract: A method is provided to enable communication between a controller and a preamplifier in a storage device. For example, the method includes implementing a serial port which is configured to transmit digital signals between the controller and the preamplifier over a single bidirectional serial data line. The serial port is controlled to selectively transmit digital signals over the bidirectional serial data line in either a first direction from the controller to the preamplifier or a second direction from the preamplifier to the controller.

Abstract: A system, method and device may be used to evaluate stacked seismic trace data. A portion of each of a number of seismic traces is isolated and an un-tuned biased volume and a tuned biased volume are produced for each trace. The un-tuned biased volume and tuned biased volume are combined to determine zones having a high probability of containing hydrocarbon resources.

Abstract: This invention is for a method for transforming a seismic trace into a compressed domain. The seismic source wavelet is transformed into a zero degree phase wavelet and a shifted 90 degree phase wavelet, and the two wavelets span a 2-dimensional sub-space. A dictionary is created by collecting the wavelets in the sub-space. In practice this dictionary is usually combined with conventional existing wavelet dictionaries. The seismic trace is projected onto the dictionary (sub-space alone or combined) to find the best matching projection, with a residual determined after each projection, wherein the sum of the residuals determines the fidelity of the data compression.

Abstract: An improved method for analyzing seismic data to obtain elastic attributes is disclosed. In one embodiment, a reflectivity series is determined for at least one seismic trace of seismic data obtained for a subterranean formation, where the reflectivity series includes anisotropy properties of a formation. One or more synthetic seismic traces are obtained by convolving the reflectivity series with a source wavelet. The one or more synthetic seismic traces are inverted to obtain elastic parameters estimates. According to one aspect, the data inputs are angle-azimuth stacks. According to another aspect, the data inputs are azimuthal Fourier coefficients, un, vn.

Abstract: A method for mapping a complex sedimentary basin is disclosed. A grid representative of the current architecture of the basin is constructed. A mechanical structural restoration is applied in three dimensions so as to reconstruct the past architectures of the basin from the current time up to a geological time t. A simulation of the geological and geochemical processes that govern the formation of a petroleum reservoir is then carried out, directly in the grids obtained from the restoration, from the geological time t to the current one. This simulation is thereafter used for mapping the sedimentary basin so as to identify zones of the basin where hydrocarbons may have accumulated.

Abstract: A method for processing seismic data. The method includes plotting a travel-time curve and one or more actual times that each seismic receiver receives one or more seismograms on a graph. The travel-time curve represents an approximate time that each seismic receiver in a seismic survey area receives the seismograms. The method may further include determining a residual static shift for each seismogram and using the residual static shift to estimate a time shift correction. The residual static shift represents a difference between an actual time in which a seismic receiver received a seismogram and a time on the travel-time curve that corresponds to the actual time. The time shift correction corrects a timing error in the time indicated by the travel-time curve.

Abstract: Sensor unit for detecting a motorized object producing a seismic or acoustic signal in the form of at least one spectral line, comprising at least one seismic sensor or at least one acoustic sensor for collecting a signal, an analog-to-digital converter for receiving said signal and generating a digital signal, a memory for storing portions of said digital signal, and a processing unit configured for performing the following operations: generating a first set of Fast Fourier Transform (FFT) values indicative of a portion of to said signal, associating said first set of FFT values with a second set of values being a partition, calculating an entropy value H of said partition, repeating the above operations, thereby constituting a sequence of entropy values H(t) corresponding to a plurality of portions of said signal, and determining a detection in case a predetermined criterion is met, said criterion is based at least on said sequence of entropy values, thereby enabling detecting of said seismic or acoustic si

Abstract: The invention is a method for performing a stratigraphically-based seed detection in a 3-D seismic data volume. The method incorporates criteria that honor the layered nature of the subsurface so that the resulting seismic objects are stratigraphically reasonable. The method may be used to extract from a seismic data volume all seismic objects that satisfy the input criteria. Alternatively, the method may be used to determine the size and shape of a specific seismic object in a seismic data volume.

Abstract: Methods of processing seismic data to remove unwanted noise from meaningful reflection signals are provided for. The seismic data is transformed from the offset-time domain to the time-slowness domain using a high resolution Radon transformation. That is, the Radon transformation is performed according to an index j of the slowness set and a sampling variable ?p; wherein j = p max - p min + 1 ? ? ? µ ? ? ? sec ? / ? m ? ? ? ? p , ?p is from about 0.5 to about 4.0 ?sec/m, pmax is a predetermined maximum slowness, and pmin is a predetermined minimum slowness. A corrective filter is then applied to enhance the primary reflection signal content of the data and to eliminate unwanted noise events. After filtering, the enhanced signal content is inverse transformed from the time-slowness domain back to the offset-time domain using an inverse Radon transformation.

Abstract: A method of seismic data processing is described in which a particular wavelet is selected from a plurality of wavelets as being most characteristic of a received seismic signal. A subtracted signal can be determined by subtracting a weighted signal of the particular wavelet from the received signal. From the subtracted signal, an additional particular wavelet can be chosen. The process of subtracting a signal and determining an additional particular one of the plurality of wavelets can be repeated until a criterion is met. The method can be repeated at several depths. The resultant spectral analysis can be used to determine, for example, an absorption coefficient.

Abstract: A method for analyzing and classifying the morphology of seismic objects extracted from a 3D seismic data volume. Any technique may be used to extract the seismic objects from the 3D seismic data volume. According to the inventive method, one or more morphologic parameters are selected for use in classifying the morphology of the selected seismic objects. Geometric analyses are then performed on each seismic object to determine geometric statistics corresponding to the selected morphologic parameters. The results of these geometric analyses are used to classify the morphology of the seismic objects according to the selected morphologic parameters.

Abstract: Methods and apparatus for seismic data compression are described, making use of a local discrete sine/cosine transform of the type IV applied to a data set which is limited by a stationary window function which reduces the overlap to the adjoining windows.

Abstract: Methods and systems are provided for orientation of multicomponent geophones, for rotating traces, and for correcting polarity differences between traces. According to an example embodiment, a receiver orientation angle is assigned, based on a determination of an angle between one or more horizontal components and one or more sources.

Abstract: A seismic reflection data acquisition and processing method and device for prospecting in tectonically complex environments are disclosed. In particular, the seismic reflection data acquisition and processing method is useful for providing a summation rate tensor field and a 3D image unit, e.g. in 3D earth seismics or complex tectonics.

Abstract: A method for attenuating source-generated surface wavetrains in a set of seismic data traces. According to the method, the seismic data traces are Fourier transformed with respect to time to determine the frequency components of the surface wavetrain. A phase matching operation is then performed using estimates of the wavenumbers for each of the frequency components to approximately align the surface wavetrain in the seismic data traces. Next, a spatial low-pass filter is used to remove the approximately aligned surface wavetrain. Finally, the phase matching is removed and an inverse Fourier transformation is performed to return the seismic data traces to the time domain.

Abstract: Methods for processing sonic logging data obtained by a sonic imaging tool or an MWD tool are provided. The sonic logging data are bandpass filtered and sampled according to techniques such as integer band decimation, quadrature modulation, and single side band modulation to provide compressed signals which can be reconstructed if desired. The compressed signals are alternatively stored for downloading and further processing, sent uphole for processing, or processed downhole. The processing preferably involves processing the analytic portion of the compressed signals according to an improved semblance processing technique where the semblance function is calculated over a time window utilizing coarse slowness and time sampling steps. The slowness and time sampling steps are dictated by the parameters of the bandpass filter and the inter-receiver spacing of the tool. The waveform for each receiver is preferably interpolated based on the time step size to provide those data points necessary for stacking.

Abstract: Disclosed is a technique for processing seismic data to enable the data to be migrated without stacking. Seismic data provided in common midpoint gathers are converted to a domain defined in terms of the travel time and the first power of velocity of reflected waves, and migration is performed in this domain. The migrated seismic data is converted back to the offset domain, wherein velocity analyses may be performed prior to stacking of the data.

Abstract: An improved method of stratigraphic analysis of geophysical data is provided. In one embodiment seismic data are transformed into one or more instantaneous attributes descriptive of the wave-like nature of the seismic signals comprising the seismic data. A stratum in the earth's subsurface, having both lateral and vertical extent, is defined on the seismic data. The instantaneous attributes within the stratum can thereafter be transformed into a descriptor statistically representative of changes in the formation materials comprising the stratum. The descriptor can then be plotted in both cross-sectional and plan view so as to identify and characterize both lateral and vertical variations in the lithology, geology and pore fluid content of the formation materials comprising the stratum.

Abstract: A method of identifying lithology of a formation traversed by a borehole from which sonic data is acquired is disclosed. The sonic data acquired comprises a data set of m waveforms, each of the waveforms including a formation wave component digitized into n samples. The formation wave component comprises direct wave components and typically reflected wave components, converted wave components, and noise. A preferred lithology identification method comprising the steps of characterizing the n samples of each formation wave component as a vector, obtaining a first eigenvector based on the formation wave component vectors, selecting a formation wave component vector, calculating a projection of the selected wave component vector on the first eigenvector, and identifying the lithology of the formation through which the selected wave component passed based on the projection of the selected wave component vector on the first eigenvector.

Abstract: A chirp signal is provided that is characterized by a flat response in the frequency domain. To achieve this response, the signal is made non-flat in the time domain. That is, its amplitude is varied as its frequency is swept. The particular perturbations introduced into the chirp's waveform are typically selected to minimize the waveform's crest factor.

Abstract: Coherent noise on seismic records is suppressed by reformatting the common shot gathers to common receiver gathers. Pairs of seismic traces from a common receiver gather are corrected for differential normal moveout, weighted in inverse relation to the RMS signal power, and combined to generate compressed common receiver gathers. The compressed common receiver gathers may be reformatted as common midpoint gathers for further processing.

Abstract: A method and apparatus for immediate, substantially real-time representation of the traces of seismic measurements in which the exponents and sign of the signal sample from the stream of data transmitted to a data recording unit (2) are uncoupled and are displayed as gradations of color on a monitor (6) of a personal computer. in this manner a quick overview of the measurement can be obtained, and the correctness of the installation and the operability of the receivers can be determined.

Abstract: A case assembly for vehicular rearview mirrors adapted to support lights for illuminating portions of the vehicle interior, instruments such as directional compasses or the like, and controls such as switches or instrument adjustment units. The case includes one, and preferably two, spaced, removable carrier modules fitted generally flush with the bottom of the mirror case. The carrier modules may include varying combinations of light assemblies for map reading, courtesy or console illumination, switches, and controls for compasses, clocks, electronic or other instruments. A preferred light arrangement provides illumination of areas below and outwardly of the case ends with brighter, targeted lighting areas in the lap areas of persons seated in the front seats of the vehicle.

Abstract: A method for processing and displaying seismic data. More particularly, a novel method for enhancing the display of common depth point seismic data. Common Depth point gathers of seismic data are processed to enhance the signal-to-noise ratio by reducing the averaging effects of lateral variations in the subterranean formation on the seismic data as well as reducing the averaging of range dependent amplitude variations in the seismic data.

Abstract: A transcriber system for receiving previously recorded data in a first medium and outputting the data in a second medium, and which includes at least one input device for receiving the data in the first medium, an output device for outputting the data in the second medium, a control and processing device which controls the input and output devices for a selected mode of transcription and in one embodiment, for selected processing of the data in the field. In one embodiment, the transcriber system receives seismic data from tape cartridges and/or solid state memory devices and outputs the seismic data onto a magnetic tape for later processing and analysis or transmission to a remote facility via a satellite link. The transcription system can include a printer/plotter for analysis of different seismic data recording and processing arrangements in the field.

Abstract: By using wave tracking rather than a downward continuation concept, two sets of elastic wave fields (one generated by a seismic source, the other recorded by multicomponent geophones) are migrated separately and are then imaged. The process is repeated for common shot gathers, and then the images (associated with each common midpoint gather), are stacked.As a consequence of wave tracking, migration operations are preferably performed in the time domain using finite difference discretization equations involving vector properties of the fields but without having to reduce the latter to one-way wave equations.

Abstract: This invention relates to a method of increasing resolution of high-intensity amplitude events in seismic records provided by common midpoint collection methods (CMP) wherein nonsymmetrical travel paths of incident and reflected rays of the generated conventional waves are taken into account prior to trace stacking irrespective of dip or depth of the target reflector. In accordance with the invention, the converted phases of the conventional seismic wave, are processed as to define a series of common reflection point (CRP) coordinates each associated with a gather of converted traces as if a source associated with a given corrected trace was placed at each CRP and activated followed immediately by the relocation of a detector at the CRP and the reception of converted phases of the generated wave comprising the trace.

Abstract: This invention relates to a method of increasing resolution of high-intensity amplitude events in seismic records provided by common midpoint collection methods (CMP) wherein nonsymmetrical travel paths of incident and reflected rays of the generated conventional waves are taken into account prior to trace stacking due to the dip and depth of the target reflector.

Abstract: This invention relates to a method of increasing resolution of high-intensity amplitude events in seismic records provided by common midpoint collection methods (CMP) wherein nonsymmetrical travel paths of incident and reflected rays of the generated conventional waves (due to dip and depth) are taken into account prior to trace stacking.

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: In accordance with the present invention, progressive changes in amplitude as a function of offset of common gathers can be more easily identified by emphasizing the degree of amplitude variation between traces of each gather along a seismic line, and after generating semblance coefficients, displaying the resulting "weighted" offset traces or representations of such traces as function of either horizontal offset or centerpoint values. A significant --and progressive --change in P-wave reflection coefficient as a function of the angle of incidence (within sections) indicates valuable characteristics, say the fluid hydrocarbon-bearing potential and/or lithology of the reflecting horizon.

Abstract: The present invention indicates that gas-containing strata of an earth formation have low Poisson's ratios and that the acoustic contrast (with the overburden rock) has a surprising effect as a function of the angle of incidence on a seismic wave associated with an array of sources and detectors: viz., a significant--and progressive--change in P-wave reflection coefficient as a function of the angle of incidence (within a gather of data) indicates the lithology of the reflecting horizon and the capping strata.

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 emphasizing the degree of amplitude variation between "near" and "far" amplitude vs. time traces of each gather along a seismic line, and displaying the resulting near and far offset sections side-by-side. A significant--and progressive--change in P-wave reflection coefficient as a function of the angle of incidence (within sections) indicates valuable characteristics, say the fluid hydrocarbon-bearing potential and/or the lithology of the reflecting horizon.

Abstract: A floating point formatter for changing fixed point serial digital data, such as that received by a seismic data acquisiton system, is disclosed wherein fixed point serial digital data is received and scaled to remove any bias added by preamplification. The scaled data is shifted a predetermined number of bits and a resulting exponent is calculated. The shifted data signal and corresponding exponent are combined and further scaled to permit stacking the data without exceeding the system capacity.

Abstract: A seismic data compression technique is disclosed which comprises sampling each individual seismic trace, operating upon a set number of samples to generate a predicted sample and quantizing the difference between the next sample and the predicted value of the sample, and transmitting the quantum number whereby the amount of information which need be transmitted is limited. In a preferred embodiment, a linear prediction differential pulse code modulation scheme is used to provide the predicted value, while an adaptive quantization scheme is used to quantize the error value to be transmitted, thus yielding further improvements in accuracy. A feedback loop can be applied to the decompression operation to limit quantization noise and further improve the fidelity of representation of the decompressed signals.

Abstract: A method for migration of velocity spectra is disclosed wherein migration of common depth point gathers is accomplished without prior determination of the velocity/depth field.

Abstract: A real-time monitor which displays analog representations of digital seismic data having been recorded on magnetic tape such that adjacent seismic traces are partially overlapped, whereby the appearance of an error is enhanced and is disclosed. The monitor display is controlled by a computer which may be of a type similar to computers used in the seismic data storage system for other purposes so that it may serve as a back-up computer. This system is implemented by incorporating into magnetic tape data storage drives read-after-write circuitry so that the data put on the tape can be read off the tape immediately thereafter and used to control the monitor means. In this way, the monitor is in fact operating in real-time and operates on precisely that data which in on the tape; thus any errors displayed on the real-time monitor include any errors made in the actual recordation of the data onto magnetic tape.

Abstract: The present invention relates to a method and apparatus for conditionally updating source-detector array parameters related to a seismic exploration system, especially during generation and collection of seismic data using a vibratory source detector array positioned at known locations along a line of survey at the earth's surface. The updated array and source parameter are generated as bits of digital data in a microcomputer system of a ground position controller housed in a recording truck associated with the exploration system of interest.

Abstract: Amplitude-versus-time information of a seismic time section is automatically migrated so that events on the time section are displaced, both vertically and horizontally, into positions on a seismic depth section that correspond to actual spatial positions of seismic reflectors in the subsurface. The migration is continuous in the sense that it moves the entire waveforms, not merely previously picked events.

Abstract: A seismic data generation and collection system is described for use in a exploration vessel for determining the subsea structure of the earth. A plurality of acoustic energy sources are towed behind the boat and acoustic waves are emitted therefrom by conventional means. The reflection at the subsea interfaces of the acoustic waves are picked up by the energy detectors which produce analog signals. These analog signals are then converted to digital data; multiple computers are used to reformat the data into a desired format. A real time monitor computer and monitor plotter may also be provided to assist the operator in evaluation of the operation of the system. The desired record format includes header information relating to the parameters under which the seismic shot was made, which may be written directly onto the magnetic tape containing the seismic data.

Abstract: A seismic cable assembly has approximately 500 equally spaced elemental sensor units to receive seismic signals generated in the earth by a seismic impulse generator or "shot". The sensor units each include 3 hydrophones or geophones spaced about 6 feet apart, for a sensor unit length of about 12 feet, to receive seismic signals up to several hundred hertz. Signals representing seismic waves received at each of these 500 units are transmitted from the cable, to a central control and recording unit, mounted in a vehicle such as a towing ship. Connected to the cable will be one or more array-forming systems for processing seismic data from the sensor to synthesize various direction-sensitive hydrophone arrays located along the seismic cable.

Abstract: The present invention indicates that gas-containing strata of an earth formation have low Poisson's ratios and that the acoustic contrast with the overburden rock has a surprising effect as a function of the angle of incidence on a seismic wave associated with an array of sources and detectors: viz., a significant--and progressive--change in P-wave reflection coefficient as a function of the angle of incidence occurs. Thus, differentiating between high-intensity amplitude anomalies of nongas- and gas-containing media is simplified: progressive change in amplitude intensity of resulting traces generated by the field array as a function of offset between each source-detector pair, is associated with the last-mentioned medium only.

Abstract: The present invention indicates that gas-containing strata of an earth formation have low Poisson's ratios and that the acoustic contrast with the overburden rock has a surprising effect as a function of the angle of incidence on a seismic wave associated with an array of sources and detectors: viz., a significant--and progressive--change in P-wave reflection coefficient as a function of the angle of incidence occurs. Thus, differentiating between high-intensity amplitude annomalies of nongas- and gas-containing media is simplified: progressive change in amplitude intensity of resulting traces generated by the field array as a function of offset between each source-detector pair, is associated with the last-mentioned medium only.

Abstract: In marine seismic exploration, the distortion introduced by an anomalous surface layer is removed from seismograms. The surface layer travel time, obtained for example from fathometer readings, is converted to a model depth section of the anomalous surface layer. Another model depth section includes an assigned control layer without the anomaly. From these two depth sections, time corrections are obtained. These time corrections are applied to the seismograms at the time of reflection from each of the subsurface interfaces.

Abstract: The specification describes methods of and apparatus for converting seismic data to migrated seismic depth sections. The apparatus includes a curve follower for following lines of continuity on seismic time sections which represent reflections from particular subsurface interfaces. The curve follower generates signals representing occurrence times and horizontal distances at successive increments along the lines of continuity. These signals are applied to a digital computer which performs a migration operation and generates signals representing the attitude, actual depth and horizontal displacement of successive points on the interfaces. An automatic plotter plots reflection segments at the correct attitude, actual depth and horizontal displacement to produce the migrated seismic depth section.

Abstract: A two dimensional display is prepared representing a cross section of the earth and designed to establish natural data lineations. The vertical axis is marked in terms of a parameter of depth below the earth's surface and along the horizontal axis, are marked seismic receiver stations. For each station, a graph of an intrinsic lithologic property as a function of depth is computed and plotted beneath the corresponding station. Contour crossing points are determined at unit intervals along the plotted graph together with the sign of the corresponding derivative. Contour crossing points, beneath adjacent stations, that match as to numerical value and derivative sign are connected by contour segments. Shading patterns are applied to the zones between contour segments to enhance the natural lineation of the chosen intrinsic lithologic function.

Abstract: A method and apparatus are provided for converting into digital form the analog ultrasonic echo signals received as a result of cyclically transmitted ultrasonic search signals intercepting an acoustic discontinuity in a workpiece. The ultrasonic echo signals are divided into a discrete number of raster-like scan lines which are scanned electronically by a microprocessor. Digital signals are generated for each line of the raster-like scan and such signals assume either a first or second state along the scan line in accordance with the signal amplitude along that line. As successive scans are made at progressively higher amplitudes of the echo signal, the amplitude required for varying the digital signal between the states for a particular scan line is incrementally increased with each scan line. A comparator receives at a first input the echo signals and at a second input a signal from a digital-to-analog converter whose output is incrementally increased on successive scan lines by the microprocessor.

Abstract: This invention relates to an improved system for employing seismic techniques for surveying the subsurface structures of the earth. The invention relates particularly to an improved system for generating, collecting and processing the data during the course of exploration with a group of trucks that travel over the surface of the earth and intermittently stop to perform the required operations. The processing aids in the performance of the generating and collecting step and in the further processing of the collected data. And the data resulting from processing in this invention are transferred to a computer center for further processing. In this system, use is made of two programmable computers to facilitate concurrent processing of seismic waves received in successive setups in different ways.