Abstract: Presented are methods and systems for deghosting seismic trace data. A cost function and one or more applicable constraints are selected and used to generate a time-variant deghosting filter. The time-variant deghosting filter can be recalculated for predetermined time intervals over the span of the associated seismic data. The time-variant deghosting filter is then applied to the seismic trace data to attenuate ghosts within the predetermined time interval. A plurality of seismic trace data can be stacked before generating and applying the time-variant deghosting filter.

Abstract: Presented are methods and systems for deghosting seismic trace data. A cost function and one or more applicable constraints are selected and used to generate a time-variant deghosting filter. The time-variant deghosting filter can be recalculated for predetermined time intervals over the span of the associated seismic data. The time-variant deghosting filter is then applied to the seismic trace data to attenuate ghosts within the predetermined time interval. A plurality of seismic trace data can be stacked before generating and applying the time-variant deghosting filter.

Abstract: A seismic source array 15 comprises a plurality of seismic source 26 arranged about a central point of the source array 15 in such a way that an imaginary circle drawn with said central point at its center, and containing all of said seismic sources 26, can be divided into at least three whole sectors each of which contains a substantially identical arrangement of seismic sources 26.

Abstract: A device including a housing defining a first chamber and a port formed through the housing. A shuttle flange moveably positioned within the first chamber. The shuttle flange moves during a gas-release cycle between i) a closed position blocking the port, and ii) an open position exposing an exit area of the port through which a compressed gas is discharged. A method for generating a seismic pressure pulse in water includes the steps of, confining a compressed gas within a chamber having a port, creating an exit area through the port by moving a shuttle along the length of the port during a gas-release cycle, pre-releasing a charge of the compressed gas through the exit area to create a pre-released bubble, choking the exit area, and producing a primary pressure pulse by releasing a main charge of compressed gas through the exit area.

Abstract: A device including a housing having an inside diameter defining a first chamber and a port formed through the housing in fluid communication with the first chamber. A shuttle flange, having a diameter, is moveably positioned within the first chamber. The shuttle flange moves during a gas-release cycle between i) a closed position blocking the port containing the compressed gas in the first chamber, and ii) an open position exposing an exit area of the port through which the compressed gas is discharged to produce a primary pressure pulse. Desirably, the primary pressure pulse produced has an average rising slope less than 2.9 bar-m/ms.

Abstract: The invention provides a method of processing seismic data acquired using a seismic source array that emits, in use, a seismic wavefield having a frequency spectrum that does not contain a source ghost at a non-zero frequency within the seismic bandwidth. This eliminates source-side ghost reflections. The method further comprises processing the acquired seismic data thereby to attenuate the effect of ghost reflections in the seismic data, and this eliminates receiver-side ghost reflections.

Abstract: A seismic source array 15 comprises a plurality of seismic source 26 arranged about a central point of the source array 15 in such a way that an imaginary circle drawn with said central point at its centre, and containing all of said seismic sources 26, can be divided into at least three whole sectors each of which contains a substantially identical arrangement of seismic sources 26.