Abstract: Disclosed are a multi-line source ground-borehole transient electromagnetic detection method and a multi-line source ground-borehole transient electromagnetic detection device. The method includes following steps: S1, constructing a multi-line source ground-borehole transient electromagnetic forward model; S2, obtaining multi-line source ground-borehole transient electromagnetic responses of an underground target layer by the multi-line source ground-borehole transient electromagnetic forward model; and S3, recognizing the underground target layer according to electromagnetic diffusion characteristics of the multi-line source ground-borehole transient electromagnetic responses. A resolution and a detection capability of the underground target by a ground-borehole transient electromagnetic method is greatly improved by adopting technical schemes.

Abstract: Disclosed are a multi-scale photoacoustic detection method of geological structure around a borehole and related devices. The method includes: obtaining depth information and direction information of the borehole; generating trajectory data of the borehole according to the depth information and direction information; obtaining an optical image of the geological structure around the borehole; generating a first velocity model according to the optical image and the trajectory data; obtaining low-frequency acoustic wave data and high-frequency acoustic wave data of the geological structure around the borehole; performing a full waveform inversion on the first velocity model according to the low-frequency acoustic wave data and the high-frequency acoustic wave data to obtain a second velocity model; and determining the geological structure around the borehole according to the second velocity model.

Abstract: One embodiment of a method for rendering one or more graphics images includes tracing one or more rays through a graphics scene; computing one or more surface normals associated with intersections of the one or more rays with one or more surfaces, where computing each surface normal includes: computing a plurality of intermediate surface normals associated with a plurality of adjacent voxels of a grid, and interpolating the plurality of intermediate surface normals; and rendering one or more graphics images based on the one or more surface normals.

Abstract: A data exchange that provides historical data indexed by date is provided. The data exchange may include a raw data layer, a model data layer, a delta staging layer, a delta database and a plurality of workspaces. The raw data layer may be a landing zone for raw data records. The model data layer may include modeled data records. The delta staging layer may be a landing zone for changed data. The changed data may correspond to changes made to the data records. The delta database may be divided into partitions. Each partition may hold data records that changed during a given time period. A plurality of data records may be continuously transferred from the raw data layer to both the model data layer and the delta staging layer. Once, during a predetermined time period, the contents of the delta staging layer may replace the contents of a partition.

Abstract: A method for enhancing properties of geophysical data with deep learning networks. Geophysical data may be acquired by positioning a source of sound waves at a chosen shot location, and measuring back-scattered energy generated by the source using receivers placed at selected locations. For example, seismic data may be collected using towed streamer acquisition in order to derive subsurface properties or to form images of the subsurface. However, towed streamer data may be deficient in one or more properties (e.g., at low frequencies). To compensate for the deficiencies, another survey (such as an Ocean Bottom Nodes (OBN) survey) may be sparsely acquired in order to train a neural network. The trained neural network may then be used to compensate for the towed streamer deficient properties, such as by using the trained neural network to extend the towed streamer data to the low frequencies.

Abstract: A least one seismic attribute is determined for each voxel of the seismic volume. A first horizon is selected for mapping and a sparse global grid is generated which includes the horizon, at least one constraint point identifying the horizon, and a number of points having a depth in the seismic volume. A value of at least one seismic attribute is determined for each point and their depths are adjusted based on the value of the seismic attribute. A map of the horizon can be generated based on the adjusted depths. Multiple local grids can be generated based on the sparse global grid, and the depths of the local grid points adjusted to generate a map of the horizon at voxel level resolution. The seismic volume can be mapped into multiple horizons, where previously mapped horizons can function as constraints on the sparse global grid.

Abstract: A non-blended dataset related to a same surveyed area as a blended dataset is used to deblend the blended dataset. The non-blended dataset may be used to calculate a model dataset emulating the blended dataset, or may be transformed in a model domain and used to derive sparseness weights, model domain masking, scaling or shaping functions used to deblend the blended dataset.

Abstract: Methods, computing systems, and computer-readable media for interpreting seismic data, of which the method includes receiving seismic data representing a subterranean volume, and determining a feature-likelihood attribute of at least a portion of a section of the seismic data. The feature-likelihood attribute comprises a value for elements of the section, the value being based on a likelihood that the element represents part of a subterranean feature. The method also includes identifying contours of the subterranean feature based in part on the feature-likelihood attribute of the section, and determining a polygonal line that approximates the subterranean feature.

Abstract: Geologic modeling methods and systems disclosed herein employ an improved simulation meshing technique. One or more illustrative geologic modeling methods may comprise: obtaining a geologic model representing a faulted subsurface region in physical space; providing a set of background cells that encompass one or more partial faults within the subsurface region; defining a pseudo-extension from each unterminated edge of said one or more partial faults to a boundary of a corresponding background cell in said set; using the pseudo-extensions and the background cell boundaries to partition the subsurface region into sub-regions; deriving a simulation mesh in each sub-region based on the horizons in each sub-region; and outputting the simulation mesh.

Abstract: Systems and methods for determining a time-dependent mud weight window are disclosed. The existence of fractures in formation rock along with a type of the formation rock are used to determine the use of a particular solution to determine the mud weight window at a particular time of a wellbore drilling operation.

Abstract: A method for correcting physical positions of seismic sensors and/or seismic sources for a seismic data acquisition system.

Abstract: Method for constructing a continuous design space for generating a physical property model in a faulted subsurface medium. The matching relationship of the fault traces on the two sides of each fault is used in a systematic way to determine the location of the fault traces in the design space. The location of any other point in the design space may then be determined by interpolation of the locations of fault traces. The fault traces are thus used as control points for the mapping. The method involves: (a) identifying the control points and determining their location in both physical and design space and (b) using selected control points, mapping any point from physical space to design space, preferably using the moving least squares method.

Abstract: It is proposed a method which comprises providing a geomechanical model of the geological environment, measurements of a first geological attribute each performed at a respective first position of the geological environment, constraints on a second geological attribute related to a yield criterion and each assigned to a respective second position of the geological environment, and a geomechanical simulator. The method also comprises determining the stress field derivable from the data outputted by the geomechanical simulator taking as input the geomechanical model and an optimal set of one or more boundary conditions. This provides an improved solution for estimating in situ stress field of a geological environment.

Abstract: Exemplary implementations may: obtain subsurface data and well data of the subsurface volume of interest; obtain a parameter model; obtain a spatial correlation model; use the subsurface data and the well data to generate multiple production parameter maps; apply the parameter model to the multiple production parameter maps to generate production likelihood values; apply the spatial correlation model to the subsurface data and the well data to generate parameter continuity values; generate a representation of the likelihood of reservoir productivity as a function of position in the subsurface volume of interest; and display the representation.

Abstract: A method for de-blending seismic data associated with an interface located in a subsurface of the earth, includes receiving blended seismic data E generated by firing N source arrays according to a pre-determined sequence Seq; selecting N sub-datasets SDn from the blended seismic data E; interpolating each selected sub-dataset SDn to reference positions ref, where the blended seismic data E is expected to be recorded, to generate interpolated data k; de-blending, in a processor, the interpolated data k to generate de-blended data o; and generating an image of the interface of the subsurface based on the de-blended data o.

Abstract: A method, including: obtaining, with a computer, an initial geophysical model; modeling, with a computer, a forward wavefield based on the initial geophysical model with wave equations including a second order z-derivative in a rotated coordinate system that accounts for a tilted transverse isotropic (TTI) medium; modeling, with a computer, an adjoint wavefield with adjoint wave equations including a second order z-derivative in a rotated coordinate system that accounts for a tilted transverse isotropic (TTI) medium, wherein the wave equations and the adjoint wave equations include relaxation terms accounting for anelasticity of earth in an update of a primary variable and an evolution relationship for the relaxation terms; and obtaining, with a computer, a gradient of a cost function based on a combination of a model of the forward wavefield and a model of the adjoint wavefield.

Abstract: Systems and methods for interpreting multi-Z horizons from seismic data are disclosed. Seismic data is displayed via a graphical user interface (GUI) of an application executable at a user's computing device. User input is received via the GUI for picking surfaces of a multi-Z horizon within a current view of the displayed data. The user's input is tracked as it is received via the GUI over a series of input points within the current view of the displayed seismic data. Based on the tracking, each of a plurality of surfaces for the multi-Z horizon and at least one edge point between the picked surfaces within the current view of the seismic data are determined. The current view of the seismic data within the GUI is dynamically updated to include a visual indication of the plurality of surfaces and the at least one edge point for the multi-Z horizon.

Abstract: The invention is a method applicable to oil and gas exploration and exploitation for automatically detecting geological objects belonging to a given type of geological object in a seismic image, on a basis of a priori probabilities of belonging to a type of geological object assigned to each of samples of the image to be interpreted. The image is transformed into seismic attributes applied beforehand, followed by a classification method. For each of the classes, an a posteriori probability of belonging to a type of geological object is determined for each of the samples of the class according to the a priori probabilities, of the class, of belonging, and according to a parameter ? describing a confidence in the a priori probabilities of belonging. Based on the class of the sample, the determined a posteriori probability of belonging to a type of geological object is assigned for the samples of the class.

Abstract: A method can include receiving spatially located geophysical data of a geologic region as acquired by one or more sensors; solving a system of equations for multi-dimensional implicit function values within a multi-dimensional space that represents the geologic region where the system of equations are subject to a smoothness constraint and subject to a weighted curvature minimization criterion at a plurality of spatially located points based on the spatially located geophysical data; and rendering to a display, a structural model of the geologic region based at least in part on the multi-dimensional implicit function values where the structural model characterizes stratigraphy of the geologic region.

Abstract: A method may include obtaining an initial velocity model regarding a subterranean formation of interest. The method may further include generating various seismic migration gathers with different cross-correlation lag values based on a migration-velocity analysis and the initial velocity model. The method may further include selecting a predetermined cross-correlation lag value automatically using the seismic migration gathers and based on a predetermined criterion. The method may further include determining various velocity boundaries within the initial velocity model using a trained model, wherein the trained model is trained by human-picked boundary data and augmented boundary data. The method may further include updating, by the computer processor, the initial velocity model using the velocity boundaries, the automatically-selected cross-correlation lag value, and the migration-velocity analysis to produce an updated velocity model.

Abstract: A method of solving a geophysical inverse problem for estimating a physical parameter, the method comprising providing a model vector representing the physical parameter, transforming the model vector by a first operator to provide a first transformed model vector, solve the inverse problem for the first transformed model vector to provide a first solution, transforming the model vector by a second operator to produce a second transformed model vector, solve the inverse problem for the second transformed model vector to provide a second solution, calculating a weighted sum of the first solution and the second solution.

Abstract: Systems and methods of performing a seismic survey are described. The system can receive seismic data. The system receives seismic data from one or more seismic data sources. The system propagates the seismic data forward in time through a subsurface model to generate a first wavefield. The system propagates the seismic data backward in time through the subsurface model to generate a second wavefield. The system combines the first wavefield with the second wavefield using a time gate imaging condition to produce subsurface images and image gathers.

Abstract: A system, apparatus, and method for optimizing structural parameters of a physical device are described. The method includes receiving an initial description of the physical device describing the structural parameters within a simulated environment. The method further includes performing a simulation of the physical device in response to an excitation source to determine a performance metric of the physical device. The simulation environment includes one or more absorbing boundaries for attenuation of an output of the excitation source during the simulation. The method further includes recording attenuated field values of the simulated environment associated with the attenuation during the simulation.

Abstract: A virtual seismic shot record is generated based at least in part on seismic interferometry of the passive seismic data. Then, a frequency bandwidth of the virtual seismic shot record is determined, wherein the frequency bandwidth comprises a plurality of frequencies. The virtual seismic shot record is transformed into a frequency-dependent seismic shot record based on a first frequency of the plurality of frequencies. Further, a phase shift is applied to the frequency-dependent seismic shot record. A first velocity model is generated from the phase shifted frequency-dependent seismic shot record. A second velocity model may be generated using full-waveform inversion (FWI). One or more depth slices are identified from the second velocity model. A seismic image is generated based on the one or more depth slices for use with seismic exploration above a region of subsurface including a hydrocarbon reservoir and containing structural features conducive to a presence, migration, or accumulation of hydrocarbons.

Abstract: Techniques are disclosed for training of factorization machines (FMs) using a streaming mode alternating least squares (ALS) optimization. A methodology implementing the techniques according to an embodiment includes receiving a datapoint that includes a feature vector and an associated target value. The feature vector includes user identification, subject matter identification, and a context. The target value identifies an opinion of the user relative to the subject matter. The method further includes applying an FM to the feature vector to generate an estimate of the target value, and updating parameters of the FM for training of the FM. The parameter update is based on application of a streaming mode ALS optimization to: the datapoint; the estimate of the target value; and to an updated summation of intermediate calculated terms generated by application of the streaming mode ALS optimization to previously received datapoints associated with prior parameter updates of the FM.

Abstract: Methods for updating a physical properties model of a subsurface region that combine advantages of FWI and tomography into a joint inversion scheme are provided. One method comprises obtaining measured seismic data; generating simulated seismic data using an initial model; computing at least one of an FWI gradient and a tomography gradient; minimizing a joint objective function E, wherein the objective function E is based on a combination of the FWI gradient and the tomography gradient or preconditioning of the FWI gradient or the tomography gradient; generating a final model based on the minimized joint objective function E; and using the final model to generate a subsurface image. The joint objective function E may be a function of one or both a FWI objective function CFWI and a tomography objective function CTomo. The joint objective function E may be defined as a weighted sum of CFWI and CTomo.

Abstract: The present disclosure describes methods and systems, including computer-implemented methods, computer program products, and computer systems, for generating a velocity model for a subsurface structure. One computer-implemented method for determining velocity model for a subsurface structure includes generating, by at least one hardware processor, a first velocity model for the subsurface structure by performing a refraction traveltime tomography procedure based on an initial velocity model; and generating, by the at least one hardware processor, a first refined velocity model based on the first velocity model and a structure skeleton model, wherein the structure skeleton model is determined based on reflection seismic data of the subsurface structure.

Abstract: A two-step inversion method for computing multi-layer subterranean formation properties includes processing gain compensated electromagnetic measurement quantities using a first inversion to compute a corresponding set of borehole corrected gain compensated measurement quantities. The first inversion includes a mathematical model of the tool and the borehole in a uniform, anisotropic formation. The set of borehole corrected gain compensated measurement quantities are then processed using a second inversion to compute multi-layer anisotropic formation properties. The second inversion includes a 1D inversion employing a point dipole model and a multi-layer formation model.

Abstract: Systems and methods for identifying potential hydrocarbon traps in a subterranean region can include: receiving seismic data of the subterranean region, the seismic data acquired by at least one seismic sensor, the seismic data indicating positions of physical barriers to hydrocarbon flow in the subterranean region and using anisotropic lateral and upward erosion to identify possible locations of hydrocarbons.

Abstract: The present disclosure describes methods and systems for fracturing geological formations in a hydrocarbon reservoir. One method includes forming a borehole in a hydrocarbon reservoir from a surface of the hydrocarbon reservoir extending downward into the hydrocarbon reservoir; transmitting an electromagnetic (EM) wave through the borehole; directing at least a portion of the EM wave to rocks at a location below the surface in the hydrocarbon reservoir; and fracturing the rocks at the location below the surface in the hydrocarbon reservoir by irradiating the rocks around the borehole using at least the portion of the EM wave, where the irradiating is performed by irradiating a first portion of the rocks by using the EM wave for a first duration and after irradiating the first portion of the rocks for the first duration, refraining from irradiating the first portion of the rocks for a second duration.

Abstract: Wavelet estimation may be performed in a reservoir simulation model that is constrained by seismic inversion data and well logs. A synthetic seismic trace is generated along with an estimated wavelet. The reservoir simulation model is revised based on results from model comparisons to actual data or base seismic data and is then used to perform a wavelet estimation. The estimated wavelet may then be used to plan further production at the well site environment, additional production at additional well site environments or any other production and drilling operation for any given present or future well site environment.

Abstract: A signal-to-noise ratio (SNR) estimation method includes an optical signal transmission step of inserting at least one pair of signal sequences into transmission data and transmitting the transmission data into which the at least one pair of signal sequences is inserted, a signal sequence extraction step of extracting the at least one pair of signal sequences from a received signal obtained by receiving the transmitted transmission data, an inner product calculation step of calculating an inner product value of the extracted at least one pair of signal sequences, a reception power calculation step of calculating reception power of the extracted at least one pair of signal sequences, and an SNR calculation step of calculating an SNR of the at least one pair of signal sequences on the basis of the calculated inner product value and the calculated reception power.

Abstract: Embodiments of the present disclosure present devices, methods, and computer readable medium for techniques for measuring operational performance metrics, and presenting these metrics through an application programming interface (API) for developers to access for optimizing their applications. Exemplary metrics can include central processing unit or graphics processing unit time, foreground/background time, networking bytes (per application), location activity, display average picture luminance, cellular networking condition, peak memory, number of logical writes, launch and resume time, frame rates, and hang time. Regional markers can also be used to measure specific metrics for in application tasks. The techniques provide multiple user interfaces to help developers recognize the important metrics to optimize the performance of their applications. The data can be normalized over various different devices having different battery size, screen size, and processing requirements.

Abstract: A system and method combines model-based inversion and supervised neural networks to develop high resolution rock property volumes from surface seismic data. These volumes have higher frequency and are calibrated to fit well log data. In addition to rock volumes, a Reflection Coefficient (RC) volume is derived from the acoustic impedance volume. The RC volume has much higher frequency, better lateral continuity, and ties to the well logs better than conventional seismic or frequency enhanced data. By interpreting and mapping with this RC volume, a much more accurate depth model can be built, which allows for a horizontal well to be accurately drilled.

Abstract: One embodiment of generating a pore pressure prediction through integration of seismic data and basin modeling includes crossplotting seismically derived velocities and effective stress at spatial coordinates; defining seismic transform functions and an uncertainty range from the crossplotting; transforming the seismically derived velocities into calculated effective stress using selected seismic transform functions and calculating pore pressure using an equation transforming the calculated effective stress into calculated pore pressure; identifying a subset of the selected seismic transform functions, where the subset is identified in response to the calculated pore pressure being adequate based on a comparison; using an inverse of the subset to convert the effective stress from the basin model into basin model derived velocities; building a hybrid velocity model by selecting velocities from the basin model derived velocities or from the seismically derived velocities in each region; and generating a digital

Abstract: The technical solution of the present application is applicable to the technical field of geophysical exploration, and provides a surface wave prospecting method and an acquisition equipment. This method comprises: obtaining vibration data by a vibration collecting device; calculating a dispersion graph by applying a vector wavenumber transform method to the vibration data, extracting dispersion curves from the dispersion graph, wherein the dispersion curves include fundamental mode and higher modes of dispersion curves of surface wave; establishing an initial stratigraphic model according to the dispersion graph; and performing a dispersion curves inversion based on the initial stratigraphic model and an inversion algorithm.

Abstract: A computer implemented method for denoising a set of seismic datasets, specifically belonging to different 3D subsets of a 4D survey the method including: (a) receiving a baseline and a monitor seismic dataset which were acquired by surveying over the same subsurface formation over different periods of time; (b) cross-equalizing the monitor seismic dataset to match to the baseline seismic dataset in terms of amplitude, frequency, phase and timing of events; (c) computing an initial 4D difference between the monitor and baseline seismic datasets; (d) formulating a common noise template from the initial 4D difference; (e) de-noising the baseline and monitor seismic datasets, independently, using the common noise template in a curvelet domain; (f) updating the initial 4D difference to form an updated 4D difference, which reflects de-noised baseline and monitor datasets from step (e); and iterating the steps (d) through (F) until the updated 4D difference satisfies a predetermined criteria.

Abstract: A method to model a subterranean formation of a field. The method includes obtaining a seismic volume comprising a plurality of seismic traces of the subterranean formation of the field, computing, based on the seismic volume, a seismically-derived value of a structural attribute representing a structural characteristic of the subterranean formation, computing, based on a structural model, a structurally-derived value of the structural attribute, the structural model comprising a plurality of structural layers of the of the subterranean formation, comparing the seismically-derived value and the structurally-derived value to generate a difference value representing a discrepancy of modeling the structural attribute at a corresponding location in the subterranean formation, and generating a seismic interpretation result based on the difference value and the corresponding location.

Abstract: A computer-implemented method for reservoir volumetric estimation, a non-transitory computer-readable medium, and a computing system. The method may include running a molecular dynamics simulation of a fluid-rock model of a first reservoir system at a plurality of pressures. The fluid-rock model includes a fluid that is at least partially adsorbed in the first reservoir system at one or more pressures of the plurality of pressures. The method may also include calculating a plurality of isothermal density profiles of the fluid in the first reservoir system, in association with the plurality of pressures using a result of the molecular dynamics simulation. The method may further include determining a first gas accumulation of the fluid in the first reservoir system for the plurality of isothermal density profiles. The first gas accumulation is at least partially a function of a pore surface area of a sample of the first reservoir system.

Abstract: Methods, apparatus, and articles of manufacture are disclosed to characterize acoustic dispersions in a borehole. An example apparatus includes a dispersion analyzer to characterize an acoustic wave dispersion in a borehole in a formation by calculating a quality indicator corresponding to the acoustic wave dispersion, and a report generator to prepare a report including a recommendation to perform an operation on the borehole based on the quality indicator.

Abstract: A method of identifying bounded hydrocarbon formations of interest in a seismic data set includes obtaining a seismic data set, pre-processing the seismic data set, inputting the plurality of graphical model inputs and one or more rules to a graphical model, wherein the rules define a relationship between a plurality of attributes of a bounded hydrocarbon formation, running a graphical model on the graphical model inputs, post-processing the graphical model outputs, and displaying the ranked clusters in order of rank.

Abstract: A multi-stage FWI workflow uses multiple-contaminated FWI models to predict surface-related multiples. A method embodying the present technological advancement, can include: using data with free surface multiples as input into FWI; generating a subsurface model by performing FWI with the free-surface boundary condition imposed on top of the subsurface model; using inverted model from FWI to predict multiples; removing predicted multiples from the measured data; using the multiple-free data as input into FWI with absorbing boundary conditions imposed on top of the subsurface model; and preparing a multiple free data set for use in conventional seismic data processing.

Abstract: Systems and methods for refining estimated effects of parameters on amplitudes are disclosed. Exemplary implementations may: (a) obtain ranges of parameter values for individual parameters within a subsurface region of interest; (b) generate a first model of the subsurface region of interest; (c) calculate a synthetic seismogram from the first model to determine corresponding amplitudes; (d) store results of applying the synthetic seismogram; (e) repeat steps (b)-(d) for multiple additional models; (f) obtain a subsurface distribution; (g) apply the subsurface distribution to the multiple models and the corresponding amplitudes; (h) generate a representation; and (i) display the representation.

Abstract: A system, method and program product for annotating visualizations with uncertainty information. A system is provided that includes a visualization importer that imports a generated visualization; an uncertainty processor that locates a region of uncertainty in the generated visualization; and a graphics annotator that generates an annotated visualization having uncertainty artifacts that visually identify the region of uncertainty.

Abstract: In an exemplary embodiment, a method and system is disclosed for developing a subterranean geomechanics model of a complex geological environment. The method can include estimating a pore pressure field, a stress field, a geomechanics property field, and a geological structure field from a geological concept model; geostatistically interpolating vectors and tensors from the estimated fields; and combining the results from the estimated fields and the geostatistically interpolated vectors and tensors to derive a geostatistical geomechanical model of the geological environment.

Abstract: A method for processing seismic data includes obtaining a velocity model, determining a critical angle for an interface represented in the velocity model based on a ratio between velocity of the seismic wave on first and second sides of the interface, determining an orientation of a normal vector extending normal to a location of the interface, determining an orientation of an arrival direction vector of a wavefield at the location of the interface, calculating an angle between the normal vector and the arrival direction vector, determining that the angle between the normal vector and the arrival direction vector is greater than the critical angle at the location, and attenuating the wavefield associated with the location in response to determining that the angle between the normal vector and the arrival direction vector is greater than the critical angle at the location.

Abstract: Sub-queries for a query are determined. The query is for retrieving a data item of a data graph. The data graph stores representations of the data item. Each representation of the data item stores knowledge represented by the data item in a different way or manner. Each sub-query corresponds to a different representation by which the data graph stores the data item. The sub-queries are evaluated to determine an appropriate representation of the data item in fulfillment of the query without duplicatively traversing the data graph, such as by reusing evaluation results of the sub-queries that overlap one another.

Abstract: A system (100) for monitoring a subterranean structure comprises an array (10) with n acoustic sensors capable of detecting P-waves and/or S-waves from the subterranean structure and a central controller (120) for receiving a signal (X) from the sensors. The system further comprises a lookup table (20) comprising a pre-computed travel time curve (24) expressed as relative arrival times of a signal from a location (Lm) to each of the sensors (1-n); a comparison unit for comparing the received signal (X) with the pre-computed travel time curve (24), and means for raising an alarm if the received signal (X) matches the precomputed travel time curve (24). Preferably, the alarm is raised if a computed semblance value (26, 27) exceeds a predefined threshold. The system may monitor several locations (Lm) in parallel using a fraction of the computer resources and time required by prior art techniques.

Abstract: Inversion techniques are provided for imaging subsurface regions from geophysical data sets. The inversion techniques provide a geophysical data set containing data measured from a subsurface region to an objective function. These techniques further optimize the objective function to invert for an implicitly represented geologic structure of the subsurface region and at least one geophysical parameter of the subsurface region. In addition, the inversion techniques use a computer system to present results produced by the objective function optimization.

Abstract: A method for monitoring condition of a wellbore includes initializing a value of at least one parameter having a relationship to likelihood of a drill string becoming stuck in a wellbore (the HCF). During drilling operations, at least one drilling parameter having a determinable relationship to the HCF is measured. In a computer, the value of the HCF is recalculated based on the at least one measured parameter. The initial value of the HCF and the recalculated values of the HCF are displayed to a user.