Abstract: A seismic surveying method and system are disclosed. The method provides a remote display representative of the quality of the coverage of a seismic survey. The method includes progressively building up at the site of the survey a first data base of data required for said display and relating to the area being covered by the survey, concurrently transmitting the data being used to build up the first data base via satellite link to a first remote location, to build up a duplicate of the first data base at said first remote location, providing access to said first remote location for the receipt of display requests from further remote locations, and in response to such requests, processing the data of said duplicate data base to provide processed data for producing said display, and compressing said processed data and transmitting it to such a further remote location for reconstitution and display thereat.

Abstract: In a method for inverting a seismic signal, an input seismic signal is represented as an input vector i(t) of length m+n−1, an output seismic signal is represented as an output vector o(t) of length m, and a finite impulse response filter is represented as a solution vector u(t) of length n, satisfying a convolutional equation i(t){circle around (x)}u(t)=o(t). An m×, n Toeplitz matrix T(t,&tgr;) corresponding to i(t) is calculated, satisfying a matrix equation T(t,&tgr;)·u(t)=o(t). Both sides of the matrix equation are transformed to a transform domain, to generate a transformed equation. Both sides of the transformed equation are pruned, to generate a pruned equation. The pruned equation is then solved. In one embodiment of the invention, the transformed domain is the frequency domain.

Abstract: An ultrasonic sensor assembly for measuring the diameter of a well while it is being drilled is provided. The sensor assembly includes a stack including an inner sound absorbing backing element, a piezoelectric ceramic disk transducer stacked outwardly adjacent the backing element, and a matching layer, preferable made of PEEK and disposed outwardly adjacent the transducer. The layers of the stack are provided within a cavity of a metal cup and are maintained in position by a flexible diaphragm preferably made of PEEK. The diaphragm is sealed with an O-ring. A window, also preferably made of PEEK, is provided against the diaphragm and is held against the diaphragm by a spring. This arrangement acoustically couples the diaphragm to the stack and improves signal recovery. The diaphragm and O-ring form a hydraulic seal between fluid/mud in the well and the stack, and operate to retain the layers of the stack.

Abstract: A method for controlled-amplitude prestack time migration of seismic data traces. According to the inventive method, common-offset gathers of the prestack seismic data traces are 3-D Fourier transformed from the space-time domain to a preselected alternate data domain, such as the frequency-wavenumber domain, the wavenumber-time domain, or the slant-stack domain. A migration operator that substantially preserves the seismic amplitudes of the original data traces is computed in the {right arrow over (p)}−z domain. This migration operator is applied to the transformed data traces in the alternate data domain, an imaging condition is applied, and the resulting migrated data traces are then transformed back to the space domain.

Abstract: A method for detection and monitoring of hydrocarbon deposits by measuring infrasonic spectral characteristics of microseismic noise of the earth. The method is used onshore and offshore for detection of hydrocarbon deposits and for monitoring of producing oil and gas fields and subsurface storage of natural gas. In one method of the invention, at least one receiver of seismic vibrations capable of recording vibrations in the infrasonic range is placed over an area being surveyed. The spectral characteristics of the microseismic noise of the earth recorded within a 2 to 5 Hz frequency range are used as a “passive” information signal. A hydrocarbon deposit is determined by the presence of a spectral anomaly on a spectrum of the passive information signal relative to a spectrum of an information signal from the area known not to contain hydrocarbons.

Abstract: A method and an apparatus for determining an amount of fertilizer to be applied to grain crops are disclosed. A fertilizer application related formula for obtaining the necessary amount of fertilizer to be applied is established by analyzing growth information including leaf blade information, fertilizer application information and quality information, all the above information being obtained in advance from a number of grains or grain crops. The formula thus established is stored in the memory. The necessary amount of fertilizer to be applied for each specific period for grain crops which are presently under growth is calculated by applying to the above formula, growth information of the grain crops presently under growth and target quality information. The growth information includes leaf blade information in relation to a specific period. The results of the calculation are displayed or printed out.

Abstract: A method for processing three-dimensional seismic data is provided. The seismic data is at least partially the result of receiving a seismic wave with a seismic receiver. At least a portion of the seismic wave is generated by a seismic source. The source and receiver are both horizontally offset and vertically offset. The method comprises binning at least a portion of the seismic data in common reflection point bins. The method comprises sorting the seismic data within the bin to create common reflection point gathers. The method further comprises analyzing velocity, and applying surface consistent statics corrections to at least a portion of the seismic data within said common reflection point gathers. The method also comprises applying a non-hyperbolic normal moveout equation to at least a portion of said seismic data, and stacking at least a portion of said seismic data within said common reflection point gathers.

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: A multi component seismic sensor which utilises orthogonal accelerometers to determine its orientation. The accelerometers may be used to measure seismic signals directly, or the system may include geophones for this purpose.

Abstract: A method for determining formation pore pressure uses seismic data to derive an initial density model. Potential fields data are then used to derive the lower boundary of anomalous density zones (e.g., salt, shale diapirs, igneous or magmatic formations) by an inversion process. The model data are integrated vertically in two or three dimensions to determine an overburden stress for the subsurface that includes a proper treatment of the anomalous density zone. The velocity measurements determined from the seismic data are used to determine the effective stress based on appropriate relationships between effective stress and velocity. The fluid pressure is then obtained as the difference between the overburden stress and the effective stress.

Abstract: A 2D inversion of true formation resistivity from dual laterolog tool measurements is accomplished using a pre-calculated look-up table. An initial earth model is derived and divided into intervals. A 2D tool response is calculated in each interval using the earth model. Matching is checked between the calculated 2D tool response and the tool measurements. The following steps are iterated until the match is satisfactory. A 1D radial tool response is derived in each interval using the pre-calculated look-up table. Shoulder bed effects are approximated in each interval by subtracting the 1D radial tool response from the 2D tool response. A non-linear least square optimization is applied at boundaries of the intervals and local maximum and minimum values in the intervals to update the earth model.

Abstract: In a drilling system for drilling a well borehole from a surface location, hydraulic calibration is performed by making a plurality of hydraulic calibration measurements, each hydraulic calibration measurement being made at a respective drill-string RPM and flow-rate within a hydraulic calibration range. A hydraulic baseline function is then determined which predicts, within a predetermined degree of accuracy, each of the plurality of hydraulic calibration measurements.

Abstract: The present invention provides a system for drilling boreholes having a downhole subassembly which contains an acoustic measurement-while-drilling system. It uses the acoustic velocity through the formations surrounding the borehole and an acoustic transmitter and a set of receivers for determining the bed boundaries surrounding the borehole formation. An acoustic isolator on the tool may be used to attenuate body waves traveling between the transmitter and the receivers. Additional attenuation of the body waves is provided by a threshold filter based upon the absolute maximum of the received signals. Semblance of the data is determined in a slowness/intercept-time domain. Coherence and semblance filtering methods are used to differentiate between reflection signals and noise. The position and orientation of the bed boundary relative to the tool are determined.

Abstract: A method for modeling geological structures beneath anomalous density zones includes receiving seismic data and using this data to derive the top of a geologic model. Non-seismic data, such as gravity or magnetic data are used to derive the lower boundary of the geologic model in an inversion process. In one embodiment, the predicted parameters are combined with seismic data to obtain a depth image and to derive a velocity model in delineating formations of interest. In another embodiment, the processed seismic data is used to further constrain the inversion of the non-seismic data. Another novel aspect of the invention is the filtering of the non-seismic data during the inversion process in a manner that is consistent with Laplace's equation.

Abstract: A method and apparatus facilitating the event-synchronized recording of data at different locations, such as may occur at and within a borehole during a Measurement-While-Drilling (“MWD”) operations. In a seismic survey the method and apparatus uses three subsystems: 1) a seismic source; 2) a borehole receiver, and 3) a pinger. When used in a borehole containing a drill string, the pinger strikes or vibrates the drill string causing an acoustic signal to traverse the drill string. The signal reaches a borehole receiver where it is detected. The signal is also reflected back up the drill steering to a sensor, nominally an accelerometer sensor, associated with a pinger where it is time-stamped by inclusive timing circuitry.

Abstract: A method for processing of seismic data traces utilizes the fact that a series of linear operations applied to vectors can be approximated by application of the linear operations to a set of basis vectors which are then scaled and summed. The method is applied to seismic data traces with a reduction in processing time provided that computation time in creating the basis vectors is small relative to the total computation time in applying the method. Theoretically there is much to be gained in terms of processing speed by implementation of this method on a vector processor that is designed to do multiply and accumulate operations quickly.

Abstract: Provided are a method, a computer program product and a system, to measure characteristics of a geologic formation, such as hydrocarbon reservoirs, that employs modeling data to remove unwanted information from a signal carrying information concerning the geologic formation. This allows obtaining accurate information concerning the resistivity of geologic formations in which a borehole has been formed and encased with a conductive liner, such as a steel casing. Specifically, it was recognized that a magnetic field produced within a borehole that has been cased is substantially similar to magnetic field produced from a borehole that was not cased, i.e., the spatial distribution and orientation to the two aforementioned magnetic fields are the same, differing only by a constant related to the casing attenuation factor. The magnetic field outside of the cased borehole is reduced in amplitude by an attenuation factor associated with the liner.

Abstract: The present invention is a method of removing at least one feature from a signal by receiving the signal in the time domain; identifying at least one frequency to be removed; identifying a number of resolution levels to which the signal will be reduced using wavelet transformation; computing at least one wavelet difference coefficient for each resolution level and at least one wavelet average coefficient for the lowest resolution level; creating a projection of each at least one frequency onto the lowest resolution level using Fourier transformation; subtracting the projection from the corresponding at least one wavelet average coefficient; and adding the results of the last step to the at least one wavelet difference coefficient.

Abstract: A method of generating a noise estimate during seismic surveying, including measuring noise energy having a plurality of frequencies in a second time interval. The second time interval having a second start time delayed from a first start time of a first time interval during which a first plurality of reflected seismic signals are present. The plurality of reflected seismic signals having the plurality of frequencies. The second time interval approximately concurrent with the first time interval to measure one of the plurality of frequencies of the noise energy different than one of the plurality of frequencies of the first plurality of reflected seismic signals that are present. A noise estimate is generated based on the noise energy measured.

Abstract: Given a spatial dataset of n dimensions, a data-driven partitioning of the dataset is effected into topographically contiguous regions using feature specific indices (for example, by examining the change in polarity of the impedance of seismic data). Then on each region, a set of features (which may be mathematical functions) is calculated (e.g., mean value of all data in the region), wherein the features are considered sufficiently descriptive of the region. Thereupon, two or more regions which are topographically contiguous are grouped together and the associated features are assembled in a structure (e.g., a vector or a matrix) to be input to a classifier.