Abstract: Method for survey design including configuring electrodes to reduce near-surface noise in the seismic response from an electroseismic survey of a subterranean formation. Different embodiments of the invention include (1) selective measurement of the surface noise to remove it from the data; (2) suppressing surface noise generation by reducing electric fields in the vicinity of some of the electrodes; (3) creating source signature differences between the near-surface seismic response and the deep response enabling the near surface response to be removed in data processing; (4) applying an external near-surface magnetic field to modulate the near-surface seismic response, enabling it to be removed in processing; and (5) constructing a partial Faraday cage to shield a near-surface region from fields generated by the electrodes.

Abstract: A method for simultaneously operating multiple seismic vibrators using continuous sweeps (little or no “listening” time between sweeps) for each vibrator, and recovering the separated seismic responses for each vibrator with the earth signature removed. Each vibrator is given a unique, continuous pilot signal. The earth response to the motion of each vibrator is measured or estimated. The vibrator motion records for each vibrator and the combined seismic data record for all the vibrators are parsed into separate shorter records. The shorter records are then used to form a system of simultaneous linear equations in the Fourier transform domain, following the HFVS method of Sallas and Allen. The equations are then solved for the separated earth responses.

Abstract: Method for interpolating aliased seismic data to generate shot records at regular shot points. The method involves sorting the data into common offsets to obtain the finer sampling in the common-offset domain, then using DMO to transform the data to zero offset to eliminate azimuth and offset variations, from which densely sampled shot records are reconstructed by an efficient Log-Stretch Inverse Shot Record DMO. The method has ready application to techniques that benefit from input data that are regularly and densely sampled, such as 3-D surface related multiple elimination and shot record wave equation migration.

Abstract: The present invention is a method of processing seismic data in which one or more seismic vibrators are activated with one or more pilot signals and vibrator motions are recorded along with seismic data. Vibrator signatures are computed from measured vibrator motions, such as the ground force signal. A desired impulse response is specified from either a measured vibrator motion or from test data or field data from a location near the location from which the seismic data was acquired. A deconvolution filter is computed from the impulse response and the vibrator signature. Alternatively, a single separation and deconvolution filter is derived from the impulse response and from vibrator signatures from multiple vibrators and sweeps. The deconvolution or deconvolution and separation filter is used to process the seismic data. The vibrators are then moved to a new location, and the activation is repeated.

Abstract: Method for enhancing resistive anomalies in electromagnetic geophysical survey data. Scaled values of a measured electromagnetic field parameter are plotted on a depth section at locations related to corresponding source/receiver locations. Scaling is performed relative to a reference signal selected to represent a baseline free of unknown resistive bodies. Scaled values are represented by a color scale in the display, and the color scale may be adjusted to enhance perceived anomalies. The method may be employed in either the frequency domain or the time domain.

Abstract: A method to extract fault surfaces from seismic data (1,3) is disclosed. The method comprises: (a) generating at least two fault sticks (5) from the same fault from at least two slices of the seismic data wherein each slice comprises at least one fault stick from the same fault, (b) constructing an initial three-dimensional fault surface (7) containing the fault sticks, and (c) reconstructing the initial fault surface (9) using a deformable surface model to fit discontinuity or coherency information in the seismic data in an iterative process. Techniques are disclosed for constructing the initial fault surface from interpreter-provided fault nodes, and for performing the deformable surface iteration by defining an energy function for the fault surface and then minimizing the surface energy.

Abstract: Seismic facies are identified in a volume of seismic data, wherein, first, a plurality of initial textural attributes representative of the volume of seismic data are calculated. Next, a probabilistic neural network is constructed from the calculated initial textural attributes. Then, final textural attributes are calculated throughout the volume of seismic data. Finally, the calculated final textural attributes are classified using the constructed probabilistic neural network.

Abstract: This invention provides a method for constructing an offshore platform by mating a self-floating deck structure with a self-floating substructure. The self-floating deck structure may be a floating pier or barge, on which the desired equipment has been mounted. Mating is achieved by at least partially submerging the substructure, positioning the pier or barge above it, and deballasting the substructure to create a vertical bearing force between the substructure and the pier or barge. Horizontal force may be transmitted between the deck and substructure by a variety of mechanical, structural, and magnetic means.

Abstract: A method is disclosed for installing a tubular member, having an upper end and a closed lower end, axially into and through an over-pressured region of the earth by using a mandrel to drive the tubular member from near the bottom, which results in a significant section of the tubular member being pulled through the over-pressured region. In another embodiment, a filler material is inserted into at least a portion of the tubular member, and the tubular member is driven from the upper end, with the filler material assisting the progression of the tubular member through the over-pressured region.

Abstract: An earthquake-compliant offshore platform for use in regions of strong earthquakes is disclosed in which the natural vibrational period of the jacket structure is preferably in the range of about 4 seconds to about 8 seconds, which is between the primary excitation period of earthquake energy and the primary storm wave period. The earthquake-compliant jacket structure is lighter than a conventional steel battered jacket for the same location and conditions and has a constant cross-section. The vibrational period of the earthquake compliant platform can be tuned by altering structural stiffness or mass.

Abstract: A method for compensating for amplitude loss in a set of seismic traces, where the amplitude loss is caused by shallow attenuation anomalies. Attenuation factors are calculated from first-arrival amplitudes for long-offset seismic data traces. Those factors are calculated by numerical methods, using matrix inversion and iteration. Those factors are used to adjust upward the amplitudes of all later-arriving seismic traces. Frequency dependent attenuation is treated by dividing the seismic traces into frequency ranges using band-pass filters, then using the above-described method within each frequency range after which the adjusted amplitudes are recombined. Amplitude variations caused by inconsistencies in the data acquisition system, such as a source strength variation, are also treated by a similar approach.

Abstract: A method for calculating seismic velocity for migration purposes as a function of subsurface spatial position that gives the seismic processing analyst direct control of the resulting migration velocity model, and includes a means to ensure that the model is consistent with RMS velocity sweeps computed from available surface seismic or other data. The method involves generating average velocities from the model to compare to the measured RMS velocity data, and comparing the model predictions to actual data on a 3-D interactive visual display allowing quick and easy model adjustment. Other available measured data besides surface seismic data maybe used to develop the model.

Abstract: A method of sparse hyperbolic inversion is used to suppress multiples in marine seismic data. By explicitly including the two-way water-bottom reflection traveltime and water-bottom reflection coefficient as part of an augmented model domain, the inversion may be successfully carried out even for intermediate water depths and sloping water bottoms. Linear noises can also be suppressed by appropriate definition of the model. The invention also has the capability of handling time-varying wavelets or several different wavelets simultaneously. This latter capability is useful in suppressing dispersive ground roll on land seismic data.

Abstract: A method for surface estimation of reservoir properties, wherein location of and average earth resistivities above, below, and horizontally adjacent to the subsurface geologic formation are first determined using geological and geophysical data in the vicinity of the subsurface geologic formation. Then dimensions and probing frequency for an electromagnetic source are determined to substantially maximize transmitted vertical and horizontal electric currents at the subsurface geologic formation, using the location and the average earth resistivities. Next, the electromagnetic source is activated at or near surface, approximately centered above the subsurface geologic formation and a plurality of components of electromagnetic response is measured with a receiver array. Geometrical and electrical parameter constraints are determined, using the geological and geophysical data.