Abstract: A method of monitoring the quality of data is disclosed. The method includes sampling a first acquired data trace to determine the amplitude of the trace at a plurality of sampling times; and determining first and second attributes for the acquired first data trace from the sampled amplitudes of the first acquired data trace, the first and second attributes being indicative of the noise content of the first acquired data trace.

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: A seismic sensor contains a geophone (4) disposed within a housing (12). The sensor is also provided with locking means (14, 19, 21) that can either lock the geophone 4 relative to the housing, or can allow the geophone to rotate within the housing. The geophone (4) is enclosed in a casing (1) which is so constructed that the overall mass distribution of the casing and geophone is uneven. The casing and geophone assembly thus adopts a preferred orientation when the sensor is unlocked. A liquid can be disposed within the housing, so that the casing (1) and geophone (4) can float when the sensor is unlocked.

Abstract: An optical geophone or hydrophone for detecting seismic vibrational energy comprising a laser material, which generates a lasing frequency signal, the frequency of which varies in accordance with vibrational energy incident upon the laser material, a light source occurring at an excitation frequency for providing excitation energy incident upon the laser material, so that the laser material emits light at the lasing frequency modulated by the vibrational energy and a fiber optic cable for transmitting the excitation frequency light to the laser material and receiving the frequency modulated lasing frequency for transmission to a receiver. The laser material comprises a first face and a second face, the first face being parallel to the second face. The first face is coated so that it passes substantially all of the lasing frequency light and reflects substantially all of the excitation frequency light.

Abstract: A method of seismic surveying using one or more vibrational seismic energy sources activated by sweep signals. The highest order harmonic that has sufficient strength to cause significant harmonic distortion of a sweep segment is determined. A number of sweep segments in excess of the number of sources is selected. Initial phase angles are selected for each sweep segment of each seismic energy source so that substantially all harmonics up to and including the highest order harmonic are suppressed. Using cascaded sweeps, seismic data are acquired and processed to substantially attenuate harmonics upto the selected order.

Abstract: A seismic data acquisition method and system are shown. The method acquires seismic data using an acoustic source capable of producing a seismic signal and an acoustic receiver in an area having periodic acoustic interference. The method includes sensing a time window in which the periodic acoustic interference at the acoustic receiver is substantially attenuated, and adjusting the acoustic source's discharge time so a desired portion f a seismic signal produced by the acoustic source arrives at the acoustic receiver within a subsequent time window.

Abstract: A seismic data acquisition technique comprises laying a seismic data cable having a plurality of spaced apart connection nodes and a plurality of sensor strings connected to the connection nodes along a line of the area to be seismically surveyed. Each sensor string comprises ten or more seismic sensors for producing respective output signals representative of a seismic signal received by them. The sensors of the sensor strings are laid out in at least two sets of groups, each group containing several of the sensors and transmitting at least one seismic signal to a connection node, and the sets of groups being disposed along respective spaced apart lines generally parallel to the line along which the seismic data cable is laid.

Abstract: A control device or “bird” for controlling the position of a marine seismic streamer is provided with an elongate, partly flexible body which is designed to be electrically and mechanically connected in series with a streamer. In its preferred form, the bird has two opposed wings which are independently controllable in order to control the streamer's lateral position as well as its depth.

Abstract: A system for collecting seismic data from geologic formations underlying water. A plurality of hydrodynamic housings are deployable in the water and are permitted to descend at a fast rate through the water until the housings contact the geologic formations. A controller engaged with each housing reconfigures the housing to enhance contact between the housing and the geologic formations and to reduce impact of ocean currents acting against the housing. A marine seismic sensor is engaged with each housing to detect seismic data and to sensor orientation. Each housing can be disconnected from the associated marine seismic sensor to facilitate retrieval of the seismic sensors to the water surface.

Abstract: An improved seismic method comprises the steps of generating seismic waves by exploding an explosive composition in a subterranean formation, wherein the explosive composition comprises a first explosive material and an oxidizable metal material, and detecting the seismic waves and/or reflections thereof with seismic detectors. Also disclosed are geophysical survey systems that comprises a seismic energy source comprising a first explosive material and an oxidizable metal material, the seismic energy source being located in a subterranean formation, and a plurality of seismic detectors that are adapted to detect seismic waves generated when the seismic energy source explodes and reflections of these waves. A method of preparing an explosive composition is also disclosed.

Abstract: A method for determination of seismic wave travel times from a surface location to at least one subsurface computation point (CP) within a plurality of subsurface location points. A velocity model of a region is defined. A complex monochromatic wavefield is computed, using the velocity model, for the at least one CP. An unwrapped phase of the seismic wave is determined at a neighboring computation point (NCP) proximate to at least one subsurface CP. The travel time of the seismic wave to the at least one CP is determined using the unwrapped NCP phase and the computed monochromatic wavefield for the at least one CP. Travel time maps and table may be created from the determined travel time values.

Abstract: A marine seismic source consists of one or more airguns (1) suspended from a float (2). A supply harness (5) is provided to supply compressed air and electrical control signals to the airguns. The airgun is mounted such that the harness (5) is below the point at which air is emitting from the airgun (1). This means that bubbles of air that rise from the airgun when it is fired do not impact on the harness and so cannot damage the harness.

Abstract: A method and computer system of processing seismic data is presented. A high-resolution Radon transform is defined for use on seismic data. The high-resolution Radon transform is regularized using a semblance measure of the seismic data. The seismic data is processed using the high-resolution Radon transform to enhance desirable features of the seismic data. A tangible representation of the processed seismic data is presented. The semblance measure of the seismic can include a semblance measure along a dimension of the seismic data.

Abstract: A method for finding an optimal path in seismic in fill shooting using a neural network to estimate cable feathering and uses multiple off set cost maps and potentials in cellular automata. The process determines cable coordinates at each cell location and store the coordinates of a predecessor cell to eliminate multiple paths.

Abstract: Streamer handling apparatus for use on a seismic survey vessel (10) comprises one or more trolleys (40) movable along a guide rail (50) over the width of stern (18) and of the streamer deck (20) of the vessel. The or each trolley (40) is provided with a clamping device (70) which can be used to grip the inboard end of part of a multi-section streamer (28) deployed over the stern end of the streamer deck (20), so facilitating the transfer of parts of streamers from one streamer (28) station to another across the width of the streamer deck (20).

Abstract: A system and method for coordinating the operation of multiple manned, remotely operated or autonomous marine vessels engaged in marine seismic data acquisition to direct cooperating vessels from one point to the next while minimizing deviations in the desired spatial configuration of assets, risk to vessels and seismic assets, and personnel and to obtain optimal midpoint coverage by evaluating inputs from subsystems providing positioning information for cooperating vessels, prospect coverage, vessel capabilities, environmental information, and navigation hazards.

Abstract: Temporal and/or spatial frequencies of spatially and digitally sampled 2-D or 3-D seismic data above the Nyquist frequency are preserved in full time migration of partial time migration (DMO) of 2-D and 3-D are preserved. Use is made of the fact that migration operators applied to input seismic data produce an output that need not correspond to prespecified temporal or spatial sampling values, and for sufficiently long migration operators, gives substantially uniform sampling at higher rates than the spatial and temporal Nyquist frequencies. Exact values of the partial migrated outputs are accumulated in an output buffer prior to combining them to give a migrated output with high temporal and/or spatial frequencies preserved.

Abstract: A non-rigid method of matching two (12, 14) or more sets of seismic data signals obtained from the same subsurface area involving the steps of decomposing (20) the sets of seismic data signals into sample sets, generating displacement vectors (26) indicating directions and amounts samples from one sample set may be translated to better match samples from the other sample set, and translating (30) samples along the displacement vectors to produce a seismic image of the subsurface area. This method is particularly adapted for use in analyzing time-lapsed seismic images of petroleum reservoirs to monitor the movement of fluids within the reservoirs.

Abstract: A system and method for generating acoustic source energy in marine seismic operations. A plurality of acoustic energy sources are integrated within seismic streamers to facilitate deployment, power distribution and signal communication. The acoustic energy sources can comprise slotted cylinders activatable with piezoelectric elements. By providing an array of lightweight, energy efficient acoustic energy sources throughout a seismic receiver array, both zero-offset and far-offset reflection data can be recorded. The acoustic energy discharge can be swept over a time interval, or steered in a selected pattern throughout the array, to significantly reduce the impulse energy released into the water. The reflected signals can be compressed back into an impulse for subsequent data processing. Bi-static reflections can be generated simultaneously with the zero-offset source-receiver locations to improve the vertical and horizontal resolution of data.

Abstract: A system for detecting source acoustic energy in seismic operations. The system is operable on land and in marine applications. On land, a piezoelectric film is positioned between a vibrator or other source baseplate and the soil. Compression of the piezoelectric film generates an electrical signal proportional to the total ground force, including force due to flexural or resonance of source components, exerted by the seismic source. In marine applications, a source displaces water to produce a pressure pulse in the water, and a piezoelectric film detects the resulting pressure pulse and the flexural movement of the source to produce an electrical signal proportional to the movement of the active component.