Abstract: An exemplary method for filtering multi-component seismic data is provided. One or more characteristics of the seismic data corresponding to a relative manifestation of surface wave noise on the different components, such as polarization attributes, are identified. A time-frequency boundary in the seismic data is also identified in the time-frequency transform domain, the time-frequency boundary delineating portions of the seismic data estimated to contain surface wave noise (302). Finally, filtered seismic data are created (306) by removing portions of the seismic data that correspond to the identified characteristics of surface waves and that are within the time-frequency boundary (303).

Abstract: An exemplary embodiment of the present invention provides a method for interpolating seismic data. The method includes collecting seismic data of two or more types over a field (401), determining an approximation to one of the types of the seismic data (402), and performing a wave-field transformation on the approximation to form a transformed approximation (405), wherein the transformed approximation corresponds to another of the collected types of seismic data. The method may also include setting the transformed approximation to match the measured seismic data of the corresponding types at matching locations (408), performing a wave-field transformation on the transformed approximation to form an output approximation (412), and using the output approximation to obtain a data representation of a geological layer (416).

Abstract: Method for deriving a reservoir property change data volume from time shifts used to time-align 4D seismic survey data (31). The time alignment is performed on at least one angle stack of 4D data to determine a time-shift data volume (32). When multiple angle stacks are used, the time shifts are corrected to zero offset. A running time window is defined, and within each window the time shifts are best fit to a straight-line function of time (depth), one angle stack at a time (33). The slopes from the straight line fits from different angle stacks are averaged at each voxel in the data volume, which yields a reservoir properties (??/?) data volume (34). This data volume may be filtered with a low-pass filter to improve signal-to-noise (35). The resulting data volume may be merged with the 4D data volume to expand its bandwidth (36), or it may be converted into a reservoir saturation and pressure change data volume (38) using a rock-physics model (37).

Abstract: The invention is a method for suppressing noise in controlled source electromagnetic survey data based on the frequency content of the noise. The invention recognizes that some data variations across bins cannot be attributed to resistivity variations within the earth. This variation across bins constitutes a model of noise in such surveys, and the invention mitigates noises that obey this model. Noise varying rapidly in either space or time is removed by filtering temporal frequency domain data (131) with a low-pass filter (134) having a selected cutoff frequency (133).

Abstract: Method for improving frequency-domain (1505), controlled-source electromagnetic data readability and interpretability in hydrocarbon prospecting by mapping a scaled amplitude or the relative amplitude (or phase) of the electromagnetic field in a scaled offset?scaled frequency plane (1510). The preferred mapping space uses the offset times the square-root of the frequency as the X-axis and the square-root of the frequency as the Y-axis. The preferred way to scale the amplitude of the electric field is to multiply it by the frequency to the power of ?1.5. Resistive anomalies in the data may be identified by comparing negative offset data (or data relative to a reference) to positive offset data (1515). The location and size of a potentially hydrocarbon-bearing resistive body may be estimated from the position of the anomaly on the map (1520).

Abstract: Method for migration of seismic data into datasets having common azimuth angle at the reflection point. A velocity model is selected that prescribes subsurface P and/or S wave velocities including any required anisotropy parameters. (41) For shot locations on a surface grid, rays are traced on to a 3D grid of points in a target region of the subsurface. (42) At least the travel times of the rays and their dip angles at each subsurface point are stored in computer memory as they are computed. (43) Using the stored ray maps, the seismic data are migrated into seismic image volumes, each volume being characterized by at least an azimuthal angle bin, the azimuthal angles being computed from said ray dip angle information (44).

Abstract: Apparatus and method for estimating the 3D orientation angles for remotely deployed devices with flexible arms such as dipole antennas of receivers used in marine controlled-source electromagnetic surveys to explore for hydrocarbons. Acoustic transponders or transducers, or other positioning sensors such as attitude sensors or strain-sensitive fiber optic cables are placed on each electrode arm of the receiver. Acoustic sensors (101) on the receiver frame (94) work in conjunction with the positioning sensor(s) (101) on the electrode arms (92) to provide accurate 3D spatial position of the receiver electrodes (93) relative to the receiver frame. Alternatively, sonar transducers mounted on the frame are used to image the electrode arms, which image can be enhanced by fixing reflectors to the arms. An attitude sensor is mounted on the receiver frame, enabling conversion of the relative electrode positions to an earth reference frame.

Abstract: Method for real time monitoring of the waveform transmitted by an electromagnetic survey source, using a near-source monitoring receiver to measure electromagnetic field and transmitting the measured signal in real time to a control location.

Abstract: A method for predicting differences in subsurface conditions useful in 4D applications. In an example embodiment of the method, at least one layer is defined in a data volume representing a first subsurface condition such as shale volume fraction (104). An exhaustive search methodology is then performed over a second subsurface condition such as pressure or saturation for some or all of the first subsurface condition data points (106) based on a data fit of synthetic geophysical data to measured geophysical data. The exemplary method may additionally comprise performing a statistical analysis to determine whether the error in data fit is significantly reduced (110) if one of the layers is divided into two or more layers (108). The layer is divided into multiple layers (114) if the error is significantly reduced (112). In this manner, the measured survey data are inverted to predict values of the second subsurface condition.

Abstract: The invention discloses a way to recover separated seismograms with reduced interference noise by processing vibroseis data recorded (or computer simulated) with multiple vibrators shaking simultaneously or nearly simultaneously (200). A preliminary estimate of the separated seismograms is used to obtain improved seismograms (201). The preliminary estimate is convolved with the vibrator signature and then used to update the seismogram. Primary criteria for performing the update include fitting the field data and satisfying typical criteria of noise-free seismograms (202). Alternative ways to update are disclosed, including signal extraction, modeled noise extraction, constrained optimization based separation, and penalized least-squares based separation. The method is particularly suited for removing noise caused by separating the combined record into separate records for each vibrator, and is advantageous where the number of sweeps is fewer than the number of vibrators (200).

Abstract: Method for transforming geologic data relating to a subsurface region between a geophysical depth domain and a geologic age domain. A set of topologically consistent surfaces (252a) is obtained that correspond to seismic data (252). The surfaces are enumerated in the depth domain. An age is assigned to each surface in the depth domain (255). The age corresponds to an estimated time of deposition of the respective surface. An age mapping volume is generated (256). An extent of the age domain is chosen. A depth mapping volume is generated (260). Both the age mapping volume and the depth mapping volume are used to transform geophysical, geologic, or engineering data or interpretations (258, 263) between the depth domain and the age domain (268) and vice versa (269). The geophysical, geologic, or engineering data or interpretations transformed by at least one of the age or depth mapping volume are outputted.

Abstract: Method for making a probabilistic determination of total seal capacity for a hydrocarbon trap, simultaneously considering both capillary entry pressure and mechanical seal capacity, and where capillary entry pressure is estimated by relating it directly to the buoyancy pressure applied by the hydrocarbon column to the top seal. The method thus considers the substantial uncertainty associated with input parameters, which uncertainty limits the utility of such analyses for robust hydrocarbon column height and fluid contact predictions. The method disclosed for estimating seal capillary entry pressure, the requisite input parameter for capillary seal capacity analysis, by inverting trap parameters avoids the need for direct measurement by mercury injection capillary capacity tests on small pieces of rock, which test results often are not available for all desired locations nor are they necessarily representative of adjacent rocks in the seal.

Abstract: Methods and systems for recovery of natural gas liquids (NGL) and a pressurized methane-rich sales gas from liquefied natural gas (LNG) are disclosed. In certain embodiments, LNG passes through a heat exchanger, thereby heating and vaporizing at least a portion of the LNG. The partially vaporized LNG passes to a fractionation column where a liquid stream enriched with ethane plus and a methane-rich vapor stream are withdrawn. The withdrawn methane-rich vapor stream passes through the heat exchanger to condense the vapor and produce a two phase stream, which is separated in a separator into at least a methane-rich liquid portion and a methane-rich gas portion. A pump pressurizes the methane-rich liquid portion prior to vaporization and delivery to a pipeline. The methane-rich gas portion may be compressed and combined with the vaporized methane-rich liquid portion or used as plant site fuel.

Abstract: Method is provided for simulating a physical process such as fluid flow in porous media by performing a fine-grid calculation of the process in a medium and re-using the fine grid solution in subsequent coarse-grid calculations. For fluid flow in subsurface formations, the method may be applied to optimize upscaled calculation grids formed from geologic models. The method decreases the cost of optimizing a grid to simulate a physical process that is mathematically described by the diffusion equation.

Abstract: Method for efficient processing of controlled source electromagnetic data, whereby Maxwell's equations are solved [107] by numerical techniques [109] such as finite difference or finite element in three dimensions for each source location and frequency of interest. The Reciprocity Principle is used [103] to reduce the number of computational source positions, and a multi-grid is used [105] for the computational grid to minimize the total number of cells yet properly treat the source singularity, which is essential to satisfying the conditions required for applicability of the Reciprocity Principle. An initial global resistivity model [101] is Fourier interpolated to the computational multi grids [106]. In inversion embodiments of the invention, Fourier prolongation is used to update [120] the global resistivity model based on optimization results from the multi-grids.

Abstract: A method and apparatus for predicting sand-grain composition and sand texture are disclosed. A first set of system variables associated with sand-grain composition and sand texture is selected (605). A second set of system variables directly or indirectly causally related to the first set of variables is also selected (610). Data for each variable in the second set is estimated or obtained (615). A network with nodes including both sets of variables is formed (625). The network has a directional links connecting interdependent nodes. The directional links honor known causality relationships. A Bayesian network algorithm is used (630) with the data to solve the network for the first set of variables and their associated uncertainties.

Abstract: A method and system for drilling a wellbore is described. The system includes a wellbore with a variable density drilling mud, drilling pipe, a bottom hole assembly disposed in the wellbore and a drilling mud processing unit in fluid communication with the wellbore. The variable density drilling mud has compressible particles and drilling fluid. The bottom hole assembly is coupled to the drilling pipe while the drilling mud processing unit is configured to separate the compressible particles from the variable density drilling mud. The compressible particles in this embodiment may include compressible hollow objects filled with pressurized gas an configured to maintain the mud weight between the fracture pressure gradient and the pore pressure gradient. In addition, the system and method may also manage the use of compressible particles having different characteristics, such as size, during the drilling operations.

Abstract: The present invention is a method for constructing a geologic model of a subsurface reservoir which is a composite sedimentary body (30) composed of many smaller fundamental sedimentary bodies (32). In one embodiment, the fundamental sedimentary bodies (32) within the composite body (30) are specified by the properties of the flow which built them, including the flow properties that existed at the local inlet (36) of each fundamental body (32). The statistical distribution of these local inlet properties is characterized throughout the composite sedimentary body (30) using either outline forms of some of the fundamental sedimentary bodies (32) or a well penetration which samples the composite sedimentary body (30).

Abstract: A method to convert seismic traces to petrophysical properties is disclosed. One embodiment of the method comprises (a) deriving a combined log seismic response from at least one petrophysical log from a well and at least one seismic trace substantially near the well, (b) convolving the combined log seismic response filter with each seismic trace to convert the seismic traces to logs of petrophysical properties, (c) outputting the petrophysical properties. Equations to derive the combined log seismic response and to convolve the combined seismic response filter are disclosed. The method may be used to output the petrophysical data as a two-dimensional cross-section or as a three-dimensional volume cube.

Abstract: An elongated hollow member (160), as shown in FIG. 1, with longitudinally disposed external vane(s) (275A–B) for securing an offshore structure to the seafloor. The external vanes help maintain the heading and bearing of the anchor during the installation process, and may also enhance the pile anchor's holding capacity.