Abstract:
The present invention relates to a method of processing data representing energy propagating through a medium (e.g., acoustic, elastic or electromagnetic energy) and describes an efficient and flexible approach to forward modeling and inversion of such energy for a given medium. The representation theorem for the wave-equation is used, in combination with time-reversal invariance and reciprocity, to express the Green's function between two points in the interior of the model as an integral over the response in those points due to sources regularly distributed on a surface surrounding the medium and the points.
Abstract:
A technique includes towing at least one seismic source in connection with a survey of a structure; and operating the seismic source(s) to fire shots, where each shot is associated with a frequency sweep. The technique includes varying phases of the frequency sweeps from shot to shot according to a predetermined phase sequence to allow noise in an energy sensed by seismic sensors to be attenuated.
Abstract:
Various implementations described herein are directed to identifying reflected acoustic signals. In one implementation, a method may include receiving initial positions of an acoustic positioning source and an acoustic positioning receiver of an acoustic positioning system in a seismic spread. The method may also include calculating an expected travel difference between the acoustic positioning source and the acoustic positioning receiver. The method may further include receiving an acoustic positioning signal from the acoustic positioning receiver. The method may additionally include calculating an actual travel difference between the acoustic positioning source and the acoustic positioning receiver based on the acoustic positioning signal. The method may further include comparing the actual travel difference to the expected travel difference. The method may also include identifying whether the acoustic positioning signal is a reflected positioning signal based on the comparison.
Abstract:
A seismic sensor device includes an elongated housing for placement at least partially into an earth surface. A plurality of particle motion sensors are contained in the elongated housing to measure translational data in a first direction, where plural pairs of the particle motion sensors are spaced apart along a second, different direction along a longitudinal axis of the elongated housing. A communication interface communicates the measured translational data to a computer system configured to compute a gradient based on respective differences of the measured translational data of the corresponding plural pairs of the particle motion sensors, and compute one or more of rotation data and divergence data using the gradient.
Abstract:
A sensor device is adapted to be installed at a land-air interface. The sensor device comprises a fluid-filled housing and a sensor arrangement supported within the housing and coupled directly to the fluid so as to detect movement thereof. A seismic sensor installation comprises a sensor device installed at a land-air boundary, wherein the sensor device comprises a fluid-filled housing and a sensor arrangement supported within the housing and coupled directly to the fluid as to detect movement thereof.
Abstract:
A seismic survey apparatus includes a plurality of serially connected electrical nodes; a power supply capable of supplying power to the electrical nodes and detecting a voltage leakage among the electrical nodes; and a software component capable of locating the leakage upon its detection. A method for use in seismic surveying includes powering a plurality of serially connected electrical nodes in a seismic surveying system; automatically detecting a voltage leakage among the electrical nodes on the power domain; and automatically locating the detected voltage leakage.
Abstract:
A method is provided for deghosting marine seismic data. Marine seismic data is provided. The marine seismic data has a total acoustic wavefield that includes an upgoing acoustic wavefield and a downgoing acoustic wavefield. A deghosting operation to determine a part of the total acoustic wavefield corresponding to one of the upgoing acoustic wavefield and the downgoing acoustic wavefield is performed. The deghosting operation accounts for a varying vertical distance between a detector of a streamer and a sea surface. One of the upgoing and downgoing acoustic wavefields in the total acoustic wavefield is identified based on a result of the deghosting operation. The downgoing acoustic wavefield is removed from the total acoustic wavefield.
Abstract:
An apparatus includes a streamer cable having one or more seismic devices disposed within a polymer body and about a core. The polymer body includes a channel defined therein for receiving one or more wires connecting the seismic devices. The wires include slack for withstanding the tensional forces experienced by the streamer cable during deployment and operation. Associated methods are also described.
Abstract:
A seismic survey system having a source array (11) coupled to a deflector device (15) that controls the position of the source array. A positioning system unit (16) is mounted on the source array to provide a signal to a controller, informing the controller of the current position of the source array so that the controller can control the position of the deflector device (15) and the coupled source array. A seismic source (14) on the source array may be triggered when the source array is at a desired location as measured by the positioning system unit. The deflector device (15) comprises one or more wings (18) in a generally vertical or, alternatively, in a generally horizontal arrangement disposed adjacent to a central body (19). The streamlined central body has connection points that allow the deflector device (15) to be connected to a tow cable (13) from the tow vessel (12) and to the source array (11).
Abstract:
A technique includes distributing particle motion sensors along the length of a seismic streamer. Each particle motion sensor is eccentrically disposed at an associated angle about an axis of the seismic streamer with respect to a reference line that is common to the associated angles. The sensors are mounted to suppress torque noise in measurements that are acquired by the particle motion sensors. This mounting includes substantially varying the associated angles.