Abstract: A towed array is provided with hot-film sensors and anemometer circuitry to calculate the angle of inclination of the towed array in real time during deployment of the towed array in a sea water environment. The hot-film sensors are arranged in pairs along the length of the towed array to increase the sensitivity of the inclination angle determinations and are located flush with an exterior surface of the towed array to minimize interference with the operation of the towed array. The pairs of hot-film sensors determine the local shear stresses on the towed array, and these measurements are converted to inclination angles using an empirically derived look-up table.

Abstract: A method for seismic surveying includes disposing a plurality of seismic sensors in a selected pattern above an area of the Earth's subsurface to be evaluated. A seismic energy source is repeatedly actuated proximate the seismic sensors. Signals generated by the seismic sensors, indexed in time with respect to each actuation of the seismic energy source are recorded. The recorded signals are processed to generate an image corresponding to at least one point in the subsurface. The processing includes stacking recordings from each sensor for a plurality of actuations of the source and beam steering a response of the seismic sensors such that the at least one point is equivalent to a focal point of a response of the plurality of sensors.

Abstract: A method for acquiring three-dimensional seismic data for sub-surface geologic features wherein a seismic source array is moved along a survey pattern having a plurality of source lines of unequal lengths that are substantially parallel to each other and intersect a receiver line. The survey pattern can be repeated in an overlapping and interleaved fashion to survey a larger area.

Abstract: An apparatus includes an array of seismic sensor units that are adapted to acquire measurements in connection with a land surface-based seismic survey. Each seismic sensor unit includes a particle motion sensor and a rotation sensor.

Abstract: The present invention comprises a method of choosing a cell structure for seismic gathers dictating a grid of azimuth-offset bins that can be of various shapes and sizes. Processes that use offset-azimuth information are optimized to operate on these cells of azimuth-offset bins and invert for seismic properties. The method provides for acquisition of 3D seismic data, selecting a seismic gather bin for sorting the data, selecting at least one cell structure for the gather that may or may not be space filling, and sorting the data in to the cell structure of the gather bin. The cell structures may be any shape including hexagonal, and may be of variable sizes and may overlap.

Abstract: An apparatus and a method for migration of three components, 3-Dimensions seismic (3-C, 3-D) data acquired by down-hole receivers and surface seismic sources. This method utilizes full 3 components reflection wave field. It uses a dynamic, vector energy mapping method to image a reflection position and maps each time sample only to its reflected image point. Therefore, this method reduces unwanted data smearing and false mirror images. This method overcomes the weakness of using only a single component trace or pre-rotated three-component traces in the 1-C or 3-C 3-D VSP migration and produces better 3-D image.

Abstract: A seismic survey system having remote acquisition modules (RAMs) for acquiring seismic signals and communicating with a central recording system (CRU) via a network of cables, other RAMs, and line tap units (LTUs), arranged in a matrix of receiver lines and base lines. Each RAM cyclically converts analog signal values to digital, forming data packets. Interrogation commands emanating from the CRU and relayed with strategic delays by intervening LTUs and RAMs are received by the RAM. Each command causes the RAM to transmit a data packet. Strategic delays are set such that the transmission capacity of the line is best utilized. Power and frequency of transmission are selectable by the CRU to optimize performance. Cables contain multiple communication pairs. The network path between the RAM and the CRU is established from the CRU and altered in event of malfunction. All types of network elements are interconnectable. Recorded samples are synchronous.

Abstract: Described are methods for obtaining seismic signals representative of properties of the earth's interior, including the steps of obtaining near-field acoustic signals recorded in the vicinity of a seismic source (13), muting from the near-field acoustic signals at least partly signals representing direct arrivals from the seismic source (13), and using a remaining part of the obtained signals as estimate of a zero-offset data set. The zero-off set data set can then be used to interpolate data from conventional acquisition location, such as streamers (11), to locations closer to the source (13).

Abstract: An arrangement for conducting a seismic survey and methods for operating a vibrator array in a seismic survey. A signal source coupled to an array of vibrators drives the vibrators with a set of signals to generate seismic signals into a survey area. Each of the signals of the set has an autocorrelation function and a cross correlation function with the other signals of the set that decays faster with time than reflections of the seismic signals from the survey area. One such set of signals includes a linear FM sweep phase-modulated by a maximal-length sequence code shifted a different number of chips for each signal.

Abstract: Method for estimating one or more ray parameters for seismograms. In one implementation, the method may include selecting a reference seismogram from a gather of seismograms, selecting a set of seismograms neighboring the reference seismogram, generating a set of seismic interferograms from the reference seismogram and the selected set of seismograms, slant stacking the set of seismic interferograms to generate a ray parameter seismic interferogram corresponding to the reference seismogram and estimating a ray parameter from the ray parameter seismic interferogram.

Abstract: An apparatus and a method for migration of three components, 3-Dimensions seismic (3-C, 3-D) data acquired by down-hole receivers and surface seismic sources. This method utilizes full 3 components reflection wave field. It uses a dynamic, vector energy mapping method to image a reflection position and maps each time sample only to its reflected image point. Therefore, this method reduces unwanted data smearing and false mirror images. This method overcomes the weakness of using only a single component trace or pre-rotated three-component traces in the 1-C or 3-C 3-D VSP migration and produces better 3-D image.

Abstract: The invention relates to a method for the acquisition of seismic data that uses sources operable to produce, when they are in a shooting station, seismic vibrations according to a sweep type shooting sequence, of predetermined duration and variable frequency. According to this method, the source and recording device clocks are synchronized, shooting is authorized for each of the sources at a series of predetermined shooting times tk,n, with k being an order number for a given source and n a source order number, between 1 and the number of sources Ns, and carried out on condition that the source is in a state to produce vibrations at such time tk,n, and the signals produced by the receivers are continuously recorded. The invention also relates to a system for seismic acquisition that implements this method.

Abstract: A method for seismic surveying includes disposing a plurality of seismic sensors in a selected pattern above an area of the Earth's subsurface to be evaluated. A seismic energy source is repeatedly actuated proximate the seismic sensors. Signals generated by the seismic sensors, indexed in time with respect to each actuation of the seismic energy source are recorded. The recorded signals are processed to generate an image corresponding to at least one point in the subsurface. The processing includes stacking recordings from each sensor for a plurality of actuations of the source and beam steering a response of the seismic sensors such that the at least one point is equivalent to a focal point of a response of the plurality of sensors.

Abstract: A method and a system for determining the position of a drill bit are presented. The method comprises determining positions of seismic wave detectors, recording seismic waves generated at the drill bit, identifying events at the drill bit, determining a plurality of relative positions of the drill bit, and determining, based at least partly on a starting position and a sum of the relative positions, an absolute position of the drill bit. The method further comprises determining a position of the drill bit at a second event in relation to a position of the drill bit at a first event, and determining a second seismic wave propagation velocity between the drill bit and at least one of the detectors, based at least partly on the determined position of the drill bit at the second event.

Abstract: The disclosure describes a method and apparatus for effectively communicating data along an acoustic transmission path. The method comprises driving an acoustic transmitter to send a data signal along the acoustic transmission path, where the signal is distorted by ambient noise. The distorted signal is input to a spaced apart plurality of sensors so that consequent time-delayed signals provide reinforcement of the basic signal and attenuation of the ambient noise component when combined.

Abstract: A multi-scale finite-volume (MSFV) method to solve elliptic problems with a plurality of spatial scales arising from single or multi-phase flows in porous media is provided. The method efficiently captures the effects of small scales on a coarse grid, is conservative, and treats tensor permeabilities correctly. The underlying idea is to construct transmissibilities that capture the local properties of a differential operator. This leads to a multi-point discretization scheme for a finite-volume solution algorithm. Transmissibilities for the MSFV method are preferably constructed only once as a preprocessing step and can be computed locally.

Abstract: The invention relates to a seismic system having an array of nodes, each capable of emitting and detecting seismic signals. The array of nodes is mounted on a mobile platform in a certain geometry and is configured to acquire subsurface data, and more particularly detect shallow buried objects, while being translated over a surface. Such a seismic system allows for high subsurface point redundancy by providing a large number of channels of data used to sum the energy at a point in the subsurface. In other aspects, the invention relates to methods for processing the acquired data to increase signal-to-noise ratio. In still other aspects, the invention relates to methods for imaging the data for visualization on a display.

Abstract: According to a preferred aspect of the instant invention, there is provided a system and method for acquiring seismic data in a marine environment, wherein at least two source vessels are used in conjunction with a recording vessel which tows a plurality of hydrophone cables. Preferably, the source vessels will be positioned along side of the towed streamer configuration and most preferably one source vessel will be located near the recording vessel and the other at the end of the streamer configuration, preferably along the same side of the streamer configuration as the lead source vessel.

Abstract: Method for determining acceptability of sensor locations used to perform a seismic survey. In one implementation, the method includes obtaining a first set of reference data, generating a first output trace from a second set of reference data estimated from the first set of reference data at a plurality of planned sensor locations, generating a second output trace from a third set of reference data estimated at a plurality of actual sensor locations and comparing the second output trace with the first output trace to determine whether the variation between the second output trace and the first output trace is less than a predetermined value.

Abstract: A receiver point arrangement is deployed having one or more receiver lines, each receiver line having receivers with substantially uniform inline spacing. A seismic source is triggered at each source point in an arrangement of source points along one or more source lines, each source line having source points with substantially uniform crossline spacing. Seismic data traces are collected, each trace having an associated midpoint. A perturbation pattern is applied to at least one of the receiver point arrangement and the source point arrangement to distribute the midpoints evenly within a bin having dimensions of half the receiver inline spacing and half the source crossline spacing across multiple locations within that bin.

Abstract: A seismic survey system having remote acquisition modules (RAMs) for acquiring seismic signals and communicating with a central recording system (CRU) via a network of cables, other RAMs, and line tap units (LTUs), arranged in a matrix of receiver lines and base lines. Each RAM cyclically converts analog signal values to digital, forming data packets. Interrogation commands emanating from the CRU and relayed with strategic delays by intervening LTUs and RAMs are received by the RAM. Each command causes the RAM to transmit a data packet. Strategic delays are set such that the transmission capacity of the line is best utilized. Power and frequency of transmission are selectable by the CRU to optimize performance. Cables contain multiple communication pairs. The network path between the RAM and the CRU is established from the CRU and altered in event of malfunction. All types of network elements are interconnectable. Recorded samples are synchronous.

Abstract: A seismic survey system having remote acquisition modules (RAMs) for acquiring seismic signals and communicating with a central recording system (CRU) via a network of cables, other RAMs, and line tap units (LTUs), arranged in a matrix of receiver lines and base lines. Each RAM cyclically converts analog signal values to digital, forming data packets. Interrogation commands emanating from the CRU and relayed with strategic delays by intervening LTUs and RAMs are received by the RAM. Each command causes the RAM to transmit a data packet. Strategic delays are set such that the transmission capacity of the line is best utilized. Power and frequency of transmission are selectable by the CRU to optimize performance. Cables contain multiple communication pairs. The network path between the RAM and the CRU is established from the CRU and altered in event of malfunction. All types of network elements are interconnectable. Recorded samples are synchronous.

Abstract: A method of obtaining a spatial model of a property of part of a subsurface formation located between underground seismic receivers in which at least two sets of pairs of seismic receivers are utilized and one pair of receivers is used to record a signal from a seimic source and obtaining a response by solving (s11(?t){circle around (x)}s21(t))=r11,21(t){circle around (x)}(s11(?t){circle around (x)}s21(t)), wherein the symbol {circle around (x)} denotes convolution and wherein s11(?t) is the time-reverse of the signal s11(t). A path-related attribute is selected from transmission response r11,21(t) that corresponds to the property of the subsurface formation and a tomographic reconstruction technique is applied to the path-related attribute to obtain the spatial model of the property of part of the subsurface formation.

Abstract: A seismic survey system having remote acquisition modules (RAMs) for acquiring seismic signals and communicating with a central recording system (CRU) via a network of cables, other RAMs, and line tap units (LTUs), arranged in a matrix of receiver lines and base lines. Each RAM cyclically converts analog signal values to digital, forming data packets. Interrogation commands emanating from the CRU and relayed with strategic delays by intervening LTUs and RAMs are received by the RAM. Each command causes the RAM to transmit a data packet. Strategic delays are set such that the transmission capacity of the line is best utilized. Power and frequency of transmission are selectable by the CRU to optimize performance. Cables contain multiple communication pairs. The network path between the RAM and the CRU is established from the CRU and altered in event of malfunction. All types of network elements are interconnectable. Recorded samples are synchronous.

Abstract: Systems and methods of reservoir fracture characterization are disclosed. In one embodiment, the method includes: 1) obtaining seismic traces; 2) combining seismic traces into gathers that reveal acoustic reflectivity as a function of offset, azimuth, and position; 3) measuring reflection anisotropy as a function of position; 4) determining a relationship between reflection anisotropy and fracture intensity measurements at specific positions; and 5) applying the relationship to reflection anisotropy measurements to create a set of fracture intensity measurements at regularly-spaced positions.

Abstract: Surface seismic sources are used to simulate crosswell data between the two wells, and, using surface receivers, reflection seismic data are obtained over the region between the two wells. Reflection data are preferably obtained from reflectors both above and below the reservoir. Tomographic analysis of the simulated crosswell and reflection data gives a model of the reservoir. Changes in the model are indicative of reservoir fluid changes, pressure changes, or compaction.

Abstract: The present invention relates to a method for estimating the position and trajectory of a drill during drilling of boreholes in rock. The method comprising the steps of determining the starting position of the drill bit and recording the received transient seismic waves generated by the drill on impact, and estimating the difference in arrival time between events. From these, the relative distances, between the positions of the drill bit at different events are calculated and from these the present position is calculated.

Abstract: An improved method of acquiring seismic data using a plurality of vibratory seismic sources including the steps of deploying a seismic sensor deploying a plurality of vibratory seismic sources at different source points; simultaneously actuating the seismic sources; acquiring seismic data attributable to the seismic sources using the seismic sensor; redeploying at least two seismic sourc, one seismic source being thereby positioned at a source point previously occupied by the other seismic source; simultaneously actuating the redeployed seismic sources; and acquiring seismic data attributable to the redeployed seismic sources using said seismic sensor.

Abstract: This invention unifies a set of statistical signal processing, neuromorphic systems, and microelectronic implementation techniques for blind separation and recovery of mixed signals. A set of architectures, frameworks, algorithms, and devices for separating, discriminating, and recovering original signal sources by processing a set of received mixtures and functions of said signals are described. The adaptation inherent in the referenced architectures, frameworks, algorithms, and devices is based on processing of the received, measured, recorded or otherwise stored signals or functions thereof. There are multiple criteria that can be used alone or in conjunction with other criteria for achieving the separation and recovery of the original signal content from the signal mixtures. The composition adopts both discrete-time and continuous-time formulations with a view towards implementations in the digital as well as the analog domains of microelectronic circuits.

Abstract: Signals from microseismic events are used to obtain a parameter of reservoir such as porosity, permeability or saturation.

Abstract: A method to analyze full waveform multiple (i.e., monopoles, dipoles, quadrupoles) acoustic measurements in a fluid-filled borehole, surrounded by a system of fractures oriented parallel to the axis of the borehole. The method uses new measurement attributes, herein referred to as dual flexure waves and leaky fracture mode.

Abstract: A system for, and method of, orienting seismic energy sources and seismic energy receivers to substantially separate a compressional wave from a vertical shear wave. The method includes reflecting a seismic energy from a subsurface interface to produce a reflected seismic energy wave that has a compressional energy and vertical shear energy associated therewith. A first seismic energy receiver is oriented such that it is aligned with an angle of emergence of the reflected seismic energy wave to thereby maximize the vertical shear energy received by a second seismic energy receiver.

Abstract: A method of seismic surveying and seismic data processing using a plurality of simultaneously recorded seismic-energy sources. An activation sequence for each of said plurality of seismic energy sources may be determined such that energy from seismic sources may be recorded simultaneously and seismic energy responsive to individual seismic sources separated into separate source records. The seismic sources are activated using an activation sequence, the recorded seismic energy in the shot recordings may be separated into source recordings responsive to individual seismic sources. The source records may be derived from the shot records using a combination of shot record summations, inversions and filtering.

Abstract: A tool generates signals indicative of shear wave slowness of the formation surrounding a borehole. The tool comprises a collar portion adapted for mounting in a drill string, a quadrupole sonic transmitter mounted to the collar portion, and a quadrupole sonic receiver array mounted to the collar spaced apart from the transmitter.

Abstract: A system for, and method of, orienting seismic energy sources and seismic energy receivers to yield discriminated horizontal and vertical shear modes. In one embodiment, the system includes: (1) an initial matrix representing wave energy produced by a selected seismic energy source and received by a selected seismic energy receiver, (2) a first transforming matrix that cooperates with the initial matrix to orient the selected seismic energy source with respect to the selected seismic energy receiver and (3) a second transforming matrix that cooperates with the initial matrix to orient the selected seismic energy receiver with respect to the selected seismic energy source, the initial matrix thereby transformed into a successive matrix containing the discriminated horizontal and vertical shear modes.

Abstract: A system for, and method of, orienting seismic energy sources and seismic energy receivers to yield discriminated horizontal and vertical shear modes. In one embodiment, the system includes: (1) an initial matrix representing wave energy produced by a selected seismic energy source and received by a selected seismic energy receiver, (2) a first transforming matrix that cooperates with the initial matrix to orient the selected seismic energy source with respect to the selected seismic energy receiver and (3) a second transforming matrix that cooperates with the initial matrix to orient the selected seismic energy receiver with respect to the selected seismic energy source, the initial matrix thereby transformed into a successive matrix containing the discriminated horizontal and vertical shear modes.

Abstract: A system and method for periodically providing information about subsurface formations in a marine environment using a non-towed seismic signal source (3) and a static array of seismic signal receivers (4) is disclosed. The seismic signal source (3) comprises a support frame (10) and a line (7) attaching the support frame to a stationary platform (2), wherein the line (7) restrains the support frame (10) in a position that is static in relation to the formation (8). The seismic signal source (3) includes eight air guns (12) attached to the support frame (10) such that the air guns (12) are discharged to provide a tapered, heavy centered, point source seismic signal at a specific location relative to the formation (8) that is reflected to the static array of seismic signal receivers (4) such that changes in the formation characteristics may be observed over time.

Abstract: A computationally efficient semi-recursive Kirchhoff migration algorithm is capable of obtaining accurate images of complex structures in complex geological environments which commonly give rise to multivalued arrivals. The method alternates wave-equation datuming (downward continuation) and Kirchhoff migration. Breaking up the complicated velocity structure into small depth regions allows traveltimes to be calculated in regions where the computation is well behaved and where the computation corresponds to energetic arrivals. Because traveltimes are computed for small depth domains, the effects of multivalued arrivals are implicitly accounted for in the migration and the adverse effects of caustics and headwaves do not develop. The invention can use any simple first-arrival traveltime algorithm, and thus benefits from the computational efficiency, robustness, and simplicity of such algorithms.

Abstract: The method consists in building a common midpoint gather of seismic traces of which the CMP point is said given point, subjecting the traces of this gather to dynamic and/or static corrections, and characterized in that the gather associated with the given point (A) is built by recording four CMP sub-gathers associated with said given point along four angular directions (1 to 4) passing through said given point, and dynamic and/or static corrections are applied to each of the four CMP sub-gathers in order to determine, for each sub-gather, a value of the curvature and/or the velocity optimizing the energy of the trace stack of the corrected sub-gather concerned, the four values thus obtained representing the components of the stacking velocity field desired for each of the reflector elements corresponding to the given point, and characterized by a vertical propagation time t0 with reflection for zero offset.Application in particular to the exploration of a medium with a complex tectonics.

Abstract: A method of acquiring seismic data locates a central position above a peaked stratigraphic subsurface. The method then positions receiver lines radially out from the central position, angularly displaced relative to one another, at equal intervals, throughout an entire circle. The method then positions shot lines between and transverse to the receiver lines. The method can also change the circle to the shape of an ellipse. For an ellipse, the receiver lines radiate from a point at the intersection of the major and minor axes of the ellipse. The receiver lines are more closely spaced about the end points of the major axis than about the end points of the minor axis. The shot lines are more closely spaced adjacent the end points of the major axis than adjacent the end points of the minor axis.

Abstract: A method and system for simulating and optimizing land seismic survey operations. The method and system utilizes spatially referenced data and nonspatial data relevant to land seismic survey operations such as high resolution satellite and airborne imagery and uses discrete event information about land seismic survey operation to simulate a land seismic survey. The output of the simulation is a detailed list of survey events. Mathematical optimization techniques are used to enhance the efficiency of the survey execution via optimal route planning and optimal allocation of survey logistical components. The invention uses a discrete event simulator which is an object-oriented software program with survey geometry objects that represent the survey design, resources objects that represent resources needed to conduct survey operations and manager objects to coordinate the resource objects within the specified survey geometry.

Abstract: An improved method for gathering traces in a 3-D seismic survey is disclosed. In one configuration, receiver lines having equally spaced geophone receivers stations are run in one direction, and lines of equally spaced shotpoint stations run orthogonal to the receiver station lines. The station spacing in each shotpoint and receiver lines is selected to produce a desired spatial resolution, and the individual lines are spaced apart by a distance equal to at least two times the station intervals. In this method, a series of common mid point gathers centered about source/receiver line intersection, referred to as "hybrid gathers" is made, where each hybrid gather includes traces from a designated number of shots in the shotpoint line of the selected intersection that are directed into a designated number of geophone receivers in the receiver line of the selected intersection.

Abstract: Processes are described for providing a data set useful for performing analysis of reflection attribute variation among traces in a window of three-dimensional seismic data, wherein the traces have a reflection point assigned thereto and wherein the traces represent recordings from shot-receiver pairs having various azimuth angles. According to one embodiment, the process comprises: assigning an offset value to a plurality of traces; fitting a substantially conical surface having a major and a minor axis to the data of the traces within the window, wherein: the major axis of the cone represents the azimuth direction having the lowest variation in the reflection attribute, and the minor axis of the cone represents the azimuth direction having the highest variation in the reflection attribute; assigning a coordinate set to the surface, wherein the coordinate set is related to a survey geometry of the data; and comparing the reflection attribute variation as a function of offset and azimuth.

Abstract: A seismic data acquisition system is featured that utilizes a series of nearly identical seismic shots (SISS) to synchronize and to communicate with novel data acquisition units (NDAU) located in the field. Each SISS seismic shot is carefully timed to provide synchronization to each NDAU, and to allow the NDAU to correct for the time drift of its internal clock. Further, each NDAU is programmed with a number of menus, which are used to interpret the seismic shots received from a seismic source. Thus, communication from a central or headquarter site to each NDAU is facilitated, allowing for a change in production schedule and other variables. In addition, the disclosed seismic data acquisition system features movable SISS source sites and overlapping production and SISS shots.

Abstract: The present invention enables both deep marine seismic surveys and site seismic surveys to be performed simultaneously. A survey vessel tows a first seismic array (6, 16, 20) for a deep survey and a second seismic array (6, 16, 20) for the site survey. The arrays are operationally distinct but may share common physical components.

Abstract: Three dimensional seismic survey data are acquired and processed using a hexagonal sampling grid. The seismic data are grouped into hexagonal bins defined by the hexagonal grid instead of into rectangular bins defined by a rectangular grid. Method and apparatus which bin the data, although described for square and regular hexagonal grids, are also applicable to rectangles and hexagons of any shape. Because hexagonal binning requires fewer gridpoints than rectangular binning, survey source or receiver interval may be increased, which may help reduce survey cost.

Abstract: A method for acquiring and processing seismic survey data from two or more seismic sources activated simultaneously or nearly simultaneously or for a single source moved to and fired at different locations. In one aspect such a method includes acquiring seismic survey trace data generated by the source or sources, attaching source geometry to the traces, soring the traces according to a common feature thereof, (e.g. to CMP order), interpolating data points for discontinuities on the traces, selecting two halves or two portions slightly more than half of the traces, filtering the trace data for each of the two portions to filter out data related to a second one of the two seismic sources, reducing the filtered trace data to two halves of the data and deleting interpolated data, and then merging the two halves to produce refined useful seismic data related to a first one of the seismic sources.

Abstract: A reverse VSP system is provided and uses a frequency-controllable modulator of an MWD tool as a downhole seismic source. The modulator has a rotor and stator arranged to provide substantially sinusoidal outputs, and is controlled to provide a "Vibroseis"-type frequency sweep (preferably from 1 Hz to 50 Hz). With the bit of the MWD tool in contact with the bottom of the borehole, the force generated by the frequency-controllable modulator will generate measurable axial compressional (P-) waves. These waves which move through the formation are detected by an array of geophones on the formation surface, and a reference signal is obtained by a kelly-mounted accelerometer or strain gauge. The reference signal and signals obtained by the geophones are processed using known signal processing techniques.

Abstract: A method of three-dimensional seismic acquisition comprising providing a plurality of substantially parallel source/receiver lines, each said source/receiver line comprising a linear array of seismic energy receivers at substantially equally spaced station intervals and a linear array of seismic energy sources located at each second station, adjacent source/receiver lines being spaced apart by two station intervals; initiating a seismic disturbance from one of said sources and receiving seismic energy at receivers disposed symmetrically about said source. Because of single direction coarse bin dimension, there is a requirement to reconstruct a uniform bin size through cooperative wavefield reconstruction in processing. The stacked common gin gathered volume of the near patch geometry of the present invention is so robust with spatially consistent, broadband signal frequencies, that accurate dealiased interpolation can be applied, e.g., by using standard F-X prediction.

Abstract: A method to analyze full waveform multiple (i.e., monopoles, dipoles, quadrupoles) acoustic measurements in a fluid-filled borehole, surrounded by a system of fractures oriented parallel to the axis of the borehole. The method uses new measurement attributes, herein referred to as dual flexure waves and leaky fracture mode.