This paper presents a new traveltime inversion method based on the wave equation. In this method, designated as wave‐equation (WT), seismograms are computed by any full‐wave forward modeling (we use finite‐difference method). The velocity model is perturbed until traveltimes from synthetic best fitted to observed in least squares sense. A gradient optimization used and formula for Frechét derivative (perturbation of with respect velocity) derived directly No picking or ray tracing necessary,...

Mapping fault planes using seismic images is a crucial and time-consuming step in hydrocarbon prospecting. Conventionally, this requires significant manual efforts that normally go through several iterations to optimize how the different connect with each other. Many techniques have been developed automate process, such as coherence estimation, edge detection, ant-tracking, name few. However, these do not take advantage of valuable experience accumulated by interpreters. We method uses...

We show that a scheme to solve the 2-D eikonal equation by finite‐difference method can violate causality for moderate large velocity contrasts [Formula: see text]. As an alternative, we present in which solution region progresses outward from “expanding wavefront” rather than square,” and therefore honors causality. Our appears be stable reasonably accurate variety of models with contrasts. The penalty is increase computational cost programming effort.

This paper presents a new algorithm for reducing noise in seismic-impedance cubes while preserving structural and stratigraphic discontinuities or edges. The method divides the vicinity of every location 3D impedance cube into number blocks as analysis point moves throughout volume. At an interior discontinuity with any orientation, process does not average values across edge because this would blur feature. Instead, smoothest neighboring value is used. main advantage smoothing that it...

Simultaneous source acquisition technology, also referred to as “blended acquisition,” involves recording two or more shots simultaneously. Despite the fact that recorded data has crosstalk from different shots, conventional processing procedures can still produce acceptable images for interpretation. This is due power of stacking process using blended with its increased redundancy and inherent time delays between various shots. It desirable separate into single shot gathers reduce noise...

Primary reflections, like multiples, can generate false images when reverse time migration (RTM) algorithms are used. The formed by the zero-lag correlation of source wavefields and primary which propagated algorithm along nonphysical paths. These paths generated strong velocity gradients or reflection interfaces two-way wave equation is Conceptually, this type artifact be removed separating up- downgoing waves, but such separation may impractical because it often requires storing entire at...

Many previously published wave-equation-based methods, which attempt to automatically invert traveltime or kinematic information in seismic data migrated gathers for smooth velocities, suffer a common and severe problem — the inversions are involuntarily unconsciously hijacked by amplitude information. To overcome this problem, we have developed new inversion methodology, referred as full-traveltime (i.e., fully dependent on traveltime) (FTI), estimate kinematically accurate velocity model...

A hybrid wave‐equation traveltime and waveform inversion method is presented that reconstructs the interwell velocity distribution from crosshole seismic data. This method, designated as WTW, retains advantages of both full wave inversion; i.e., it characterized by reasonably fast convergence which somewhat independent initial model, can resolve detailed features model. In principle, no picking required computational cost WTW about same for inversion. We apply to synthetic data field...

We develop an algorithm based on a convolutional neural network (CNN) that detects faults directly from 3D seismic amplitude images. Our is trained with human-labeled 2D images sliced cubes, where each pixel labeled as either fault or non-fault. After training, the CNN predicts probabilities at every location in image. The test results synthetic and field data suggest locations high accuracy. With capability of emulating human experience evolving via training new datasets, technology shows...

A parsimonious staggered grid differencing scheme is presented which requires less storage than the conventional method. For three dimensional elastic wave propagation, this only stores displacement components, not stress, and so 66% of memory needed by standard The requirement same as 2–2 used Kelly et al. (1976) for second‐order equation. Its advantage that it stable accurate media with fluid‐elastic contacts a wide range Poisson ratios. disadvantage its computer programming more involved.

The Hilbert transform (HT) has been used in seismic data processing and interpretation for many years. A well-known application of HT is complex-trace analysis using instantaneous phase, frequency, amplitude (Taner et al. 1979). We present a new generalized (GHT), which advantages over the traditional HT—particularly robustness to noise variety applications.

Inversion methods based on gradient optimization techniques require the directional derivative of data with respect to model parameters. Unfortunately, (e.g., pressure seismograms) are usually restricted that explicitly given in fundamental governing equation wave equation). This limited choice type may lead misfit functions pathologically non-linear We present a methodology which allows for calculation derivatives skeletalized sets, yet still uses equations without need approximations....

We have developed an interferometric interpolation method for filling in trace gaps common-shot gathers. There are two steps implementation. First, virtual traces created the by crosscorrelating recorded a shot gather followed summing correlated pairs over all positions. Second, 1D matching filter is applied to predicted events correct wavelet and amplitude distortions. By using assumption (assuming layered medium around midpoint common-midpoint (CMP) gather), can be CMP It fully data-driven...

The seismic acquisition technology, referred to as "simultaneous sources", records two or more shots (ignited with random delay time) in a single shot gather. Despite the fact that recorded data is blended among different gathers, conventional processing procedures could still produce acceptable images for interpretation. However, separating into gathers desirable further improving image quality. This paper introduces new Multi‐Directional Vector‐Median Filter (MD‐VMF) separate gathers....

Despite the explosion of new, innovative technologies in area multiple identification and subsequent attenuation, their applicability is mostly limited to marine environments especially deep water. In land seismic data sets however, application such multiple-elimination methodologies not always straightforward many cases poor results are obtained. The unique characteristics (i.e., noise, statics coupling) major obstacles estimation elimination. well-defined surface multiples present rarely...

We have developed a fast and practical wave-equation-based migration method to image subsurface diffractors. The is composed of three steps in our implementation. First, it decomposes extrapolated receiver wavefields at every imaging point into local plane waves by linear Radon transform; the transform realized novel computationally efficient recursive algorithm. Second, decomposed are zero lag-correlated with incident source wavefields, where angles computed via structure tensor approach....

SUMMARY Train traffic has been recognized as a powerful noise source for subsurface imaging and monitoring due to its properties of being strong, economic repeatable. Compared with the traditional train, high-speed train (HST) runs faster generates vibrations that also manifest periodical signals but more striking feature sharp equidistant spectral lines in frequency spectrum. Like generated by HST-induced can be utilized after retrieval interstation impulse responses using seismic...

In the implementation of migration multiples, reverse time (RTM) is superior to other algorithms because it can handle steeply dipping structures and offer high-resolution images complex subsurface. However, RTM results using two-way wave equation contain high-amplitude, low-frequency noise false generated by improper paths in velocity model with sharp interfaces or strong gradients. To improve imaging quality we separate upgoing downgoing waves propagation source receiver wavefields. A...

The main difficulty with iterative waveform inversion is that it tends to get stuck in local minima associated the misfit function. To mitigate this problem and avoid need fit amplitudes data, we have developed a wave-equation method inverts traveltimes of reflection events, so less prone problem. Instead function, penalty function was crosscorrelation downgoing direct wave upgoing at trial image point. time lag, which maximized amplitude, represented reflection-traveltime residual (RTR)...

In seismic exploration, picking first arrival traveltimes is an important step toward the estimation of subsurface velocity model, which has direct impact on well placement. this letter, we present a 3-D deep learning method for automatic picking. specific, employ supervised U-shaped full-convolutional network (3-D U-Net) to classify each sample in data into two categories: samples before and after break. Subsequently, delineate surface separate these categories, such corresponding desired...

PreviousNext No AccessSEG Technical Program Expanded Abstracts 1990Wave‐equation traveltime inversionAuthors: Yi LuoGerard T. SchusterYi LuoUniversity of Utah and Gerard SchusterUniversity Utahhttps://doi.org/10.1190/1.1889952 SectionsAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InReddit Permalink: https://doi.org/10.1190/1.1889952FiguresReferencesRelatedDetailsCited byMitigating the effect errors in source parameters on seismic...

The structural tensor method can be used to compute dips and azimuths (i.e., orientation) encased in seismic data. However, this may produce erratic uninterpretable orientations when noisy data are encountered. To overcome difficulty, we incorporate a data-adaptive weighting function reformulate the gradient tensor. In our experiment, squared instantaneous power is adopted as weight factor; simplify computation phase input. real examples illustrate that such more interpretable spatially...

Reverse‐time migration (RTM), based on the full two‐way wave equation, has gained interest and become a popular imaging tool for complex structures in last few years. The method is well‐known its ability to better image steeply dipping overturned than methods one‐way equation extrapolation. However, RTM often contains low frequency back‐scattering noise, quality sensitive velocity. In order improve make less velocity model, we developed an de‐blending technique which separates upgoing...