Abstract: An invention that relates to streamers is described. These streamers contain one or more streamer sections. These sections can have sensors, channels, and/or analogue arrays of sensors are disposed along its length. At least one of these streamer sections has a variable density of sensors, channels, and/or analogue arrays along the length.

Abstract: Methods and apparatuses for processing seismic data to generate images or determine properties of an interior section of the Earth. The seismic data is processed to filter coherent noise such as ground roll noise from seismic survey data. The noise is attenuated using 3D and/or 2D fan filters, which may have combined low-pass and band-pass filters derived from signal decomposition. The filters are designed with selected operator length, velocity bands of signals and noises and frequency range for a primary trace and adjacent traces within the operator length. The data is decomposed with the filters into signals and noises, and the noises are then filtered from the decomposed data. The process may be repeated for various frequencies and traces within the seismic data. The methods may be used for surveys that have either regular or irregular seismic receiver or seismic source positions.

Abstract: A method for removing noise from a three-dimensional representation of seismic data. The method includes receiving seismic data acquired in a seismic survey. The method may organize the acquired seismic data into a three-dimensional representation of the acquired seismic data. The method may then remove a noise from the three-dimensional representation of the acquired seismic data based on at least one criterion.

Abstract: A method for processing microseismic data, comprises: receiving the microseismic data acquired by one or more multicomponent sensors; convolving the microseismic data with an operator that is applied to all of the components of the microseismic data; and applying a multicomponent filter operator to the convolved microseismic data. The microseismic data may result from human activity or be entirely natural. The filtering preserves the polarity of the received data whilst improving the signal-to-noise ratio of the filtered data.

Abstract: A technique includes processing seismic data indicative of samples of at least one measured seismic signal in a processor-based machine to, in an iterative process, determine basis functions, which represent a constructed seismic signal. The technique includes in each iteration of the iterative process, selecting another basis function of the plurality of basis functions. The selecting includes based at least in part on the samples and a current version of the constructed seismic signal, determining a cost function; and interpreting the cost function based at least in part on a predicted energy distribution of the constructed seismic signal to select the basis function.

Abstract: Methods and apparatuses for processing seismic data to generate images or determine properties of an interior section of the Earth. The seismic data is processed to filter coherent noise such as ground roll noise from seismic survey data. The noise is attenuated using 3D and/or 2D fan filters, which may have combined low-pass and band-pass filters derived from signal decomposition. The filters are designed with selected operator length, velocity bands of signals and noises and frequency range for a primary trace and adjacent traces within the operator length. The data is decomposed with the filters into signals and noises, and the noises are then filtered from the decomposed data. The process may be repeated for various frequencies and traces within the seismic data. The methods may be used for surveys that have either regular or irregular seismic receiver or seismic source positions.

Abstract: Described herein are implementations of various technologies for a method. The method may receive a baseline survey dataset for a region of interest. The method may obtain a transformed dataset from the baseline survey dataset using a transform. The method may determine sparsity characteristics from the transformed dataset. The method may determine survey parameters using the sparsity characteristics. The survey parameters may be for a monitor survey for the region of interest.

Abstract: A technique includes receiving seismic data acquired in a seismic survey in the vicinity of a reflecting interface. The survey has an associated undersampled direction. The technique includes providing second data indicative of discrete samples of incident and reflected components of a continuous seismic wavefield along the undersampled direction and relating the discrete samples to a linear combination of the continuous incident and reflected seismic wavefields using at least one linear filter. Based on the relationship, an unaliased representation of the linear combination of the continuous incident and reflected seismic wavefields is constructed.

Abstract: A method for removing noise from a three-dimensional representation of seismic data. The method includes receiving seismic data acquired in a seismic survey. The method may organize the acquired seismic data into a three-dimensional representation of the acquired seismic data. The method may then remove a noise from the three-dimensional representation of the acquired seismic data based on at least one criterion.

Abstract: A technique includes obtaining pressure data that was acquired by seismic sensors towed as part of a three-dimensional spread of streamers and obtaining particle motion data, which are indicative of particle motion at locations of the sensors. The technique includes estimating cross-line spectra of the pressure data based at least in part on the pressure data, and the technique includes deghosting the particle motion data based at least in part on the estimated cross-line spectra.

Abstract: A technique includes processing seismic data indicative of samples of at least one measured seismic signal in a processor-based machine to, in an iterative process, determine basis functions, which represent a constructed seismic signal. The technique includes in each iteration of the iterative process, selecting another basis function of the plurality of basis functions. The selecting includes based at least in part on the samples and a current version of the constructed seismic signal, determining a cost function; and interpreting the cost function based at least in part on a predicted energy distribution of the constructed seismic signal to select the basis function.

Abstract: An iterative process is described for obtaining a finite impulse filter to remove noise from seismic data through an iterative process with constraints on the filter applied in both, the original space-time and the transform frequency wave number at each iteration step.

Abstract: A method of processing seismic data comprises transforming seismic data which contain coherent noise to a domain in which at least some of the coherent noise is transformed to incoherent noise. The seismic data are then filtered in the new domain, to remove or attenuate the incoherent noise. If desired, the filtered data may subsequently be transformed back to the domain in which the data were acquired. The filtering process may be carried out using a multichannel interference canceller. A seismic data trace to be filtered is input to the principal channel of the interference canceller, and one or more other seismic data traces are input to the interference canceller as reference traces. Use of seismic data traces as the reference trace(s) avoids the need to determine a noise reference trace.

Abstract: A method of attenuating noise in three dimensional seismic data using a projection algorithm is disclosed. A frequency—space—space (“f-xy”) projection algorithm is used which is a generalization of the f-x projection algorithm. The predictability of the seismic signals in the f-xy domain constitutes the basis of the algorithm. Specifically it is demonstrated that if the seismic events are planar in the t-xy domain, then in the f-xy domain they consist of predictable signals in the xy-plane for each frequency f. A crucial step of the 2-D spectral factorization is achieved through the helical coordinate transformation. In addition to the disclosed general algorithm for arbitrary coherent noise, a specialized algorithm for random noise is disclosed. It has been found that the disclosed projection algorithm is effective even in extreme cases of poor signal to noise ratio. The algorithm is also signal preserving when the predictability assumptions hold.