Often a prisoner can see the sky from jail only through grid. Thus, grid may hide moon or some landscape detail. In this case, he solve problem by moving his head just bit. He will lose other detail but desired one. Because remembers details seen before, mind reconstruct image would get out of jail—without Actually, there is another way for reducing annoyance; could stretch so that it does not any interesting view. However, more difficult (and less legal) and usually adopted goals (e.g., escapes).

The solutions of traveltime inversion problems are often not unique because the poor match between raypath distribution and tomographic grid. However, by adapting local resolution iteratively, means a singular value analysis matrix, we can reduce or eliminate null space influence on our earth image: in this way, get much more reliable estimate velocity field seismic waves. We describe an algorithm for automatic regridding, able to fit available raypaths, which is based Delaunay triangulation...

In time‐lapse analysis, we have to distinguish the seismic response changes due oil and gas production at a reservoir over years from several other causes, such as recording signature random noise. this paper, focus our attention on velocity macromodel provided by tomography, which is basic tool for data regularization, its depth or time migration, possible final subtraction among different vintages. We show first that cannot use just single model all sets, because of seasonal variations...

The possible nonuniqueness and inaccuracy of tomographic inversion solutions may be the result an inadequate discretization model space with respect to acquisition geometry velocity field sought. Void pixels linearly dependent equations are introduced if grid shape does not match spatial distribution rays, originating well‐known null space. This is a common drawback when using regular pixels. By definition, depend on picked traveltimes, so we cannot eliminate it by minimising traveltime...

The correct simulation of wave propagation with direct grid methods at fluid–solid interfaces requires a proper implementation the boundary condition, which involves continuity normal component particle velocity and traction. horizontal velocities can differ (slip) tangential traction vanishes. challenge is to model interface waves, are relevant when source receiver located close interface, in particular Scholte leaky (or pseudo, or generalized) Rayleigh waves. explicit modelling based on...

Tomographic inversion of traveltimes is often carried out by discretizing the Earth as a grid regular pixels. This choice simplifies related ray-tracing algorithms, but contributes significantly to non-uniqueness estimated velocity distribution. A singular value decomposition tomographic matrix enables one recognize causes this mathematical ambiguity in model space. more intuitive than introducing arbitrary damping factors and spatial filters, allows control solutions modifying pixel...

We define an algorithm in the time domain for computing unwrapped instantaneous phase and its derivative, frequency, using only derivatives integrals. It does not require user-defined parameters, like most algorithms proposed so far. validate compare performance with respect to open-source commercial software by synthetic real data examples.

The instantaneous phase of a complex trace is normally computed as an inverse tangent function the ratio between its imaginary and real parts. This algorithm often produces discontinuous in range [[Formula: see text], [Formula: text]], principal value assumed. attempt removing these discontinuities, called unwrapping, introduces uncertainties some personal bias because it requires user-defined parameters. A new that does not require any parameters presented with related software code...

We discuss some processing steps of a marine 3-D data set from the Oseberg field, North Sea. compare prestack depth‐migrated images obtained by velocity fields provided different tools: spectra, reflection tomography, and joint tomographic inversion reflected refracted arrivals. The last ones are definitely better. also produced synthetic example modeling estimated earth structure actual recording geometry, we reached similar conclusions. correlation between signals may be unclear for later...

ABSTRACT In land surveys, the weathering layer can often distort seismic signal due to it passing through rapid velocity and density changes, dispersion, scattering inelastic absorption. a simple spring‐dashpot model for earth response, an equivalent medium groups these complex phenomena into two parameters only; are called ground viscosity stiffness. The most recent controllers vibrators estimate both parameters. To validate measurements, Saudi Aramco conducted experiment measuring...

ABSTRACT The orientation of three‐component borehole geophones used for recording during a microseismic monitoring experiment is estimated. standard technology deploying multi‐component in deep wireline‐based, which the azimuthal rotation geophone string cannot be controlled. Each receiver can have different angle that compensated by particle motion analysis direct P‐wave arrivals, picked from walk‐around VSP carried out proximity well. Knowing receivers critical, as inaccuracies lead to...

Introduetion Traveltime inversion usually treats only reftected and transmitted arrivals. This is due to two main reasons: first, in conventional hydrocarbon exploration, acquisition processing parameters are optimized for these type of waves, whereas others (e.g. refracted or diffracted) attenuated as an undesired noise; secondly, the most popular ray tracing techniques (based on Snell's law eikonal equation) not ab Ie model diffracted waves. During last few years, various based Fermat's...

This paper discusses a multivariate approach aimed at geophysical characterization of subsurface rocks for groundwater exploration in arid environments. We integrate several findings obtained from single-source, single-sensor seismic profile with gravity data to detail the tectonic settings and characterize subsurface, water-bearing formations Al Jaww Plain, one most important reserves United Arab Emirates. The have been acquired framework first EAGE Middle-East Bootcamp. Edge-detection...

The processing of Chirp data is limited by the usual recording signal envelope, which enhances its immediate visibility but prevents applying methods based on wave equations. This normally not case for Boomer data. However, both systems are monochannel instruments, cannot estimate properly propagation velocity in rocks. In this paper, we present two theorems: first one links or source spectrum with an expected amplitude decay curve; second defines conditions deconvolution stability enveloped...

ABSTRACT Passive seismic provides additional illumination sources in producing reservoirs, improving the Earth's imaging obtained by standard 3D surveys. The joint tomographic inversion of surface and borehole data, both active passive, even allows delineation thin reservoirs that cannot be resolved reflection tomography. As an application example, we present a feasibility study for real case CO 2 geological storage, showing this operation may benefit environment reservoir monitoring. origin...

The shallow P velocity provides relevant information for offshore engineers, in planning pipelines, piers, and platforms. Standard multichannel surveys trailing long cables provide good estimates but may require stopping other ongoing operations or affect the environment. Monochannel by Boomer systems involve a very short cable, so those drawbacks are minimized; however, this comes at cost of loss estimating layers. In paper, we present new method exploiting multiple reflections...

Abstract A new method to trace rays in irregular grids based on Fermat's principle of minimum time is introduced. Besides the usual transmitted and reflected waves, refracted, diffracted converted waves can also be simulated. The proposed algorithm fast stable, respects reciprocity between source receiver better than procedures adopting shooting method. It particularly suited form part a traveltime inversion procedure. use allows adaptation earth discretization available acquisition geometry...

ABSTRACT The shallowest few hundred metres of the earth cannot be adequately imaged by conventional seismic when tuned for deeper targets. Adding independent measurements (such as uphole or shallow refraction surveys) reduces this information gap, but in some arid areas Saudi Arabia) near‐surface complexities are not well resolved, even way. joint tomographic inversion different wave types can contribute to reducing these ambiguities further, complementing penetration ranges and propagation...

ABSTRACT Accurate statics calculation and near‐surface related noise removal require a detailed knowledge of the velocity field. Conventional seismic surveys currently are not designed to provide this information, 3D high‐resolution reflection/refraction acquisition is feasible for large survey areas. Satellite images vibrator plate attributes dense low‐cost data, which can be used in spatially extrapolating velocities from sparse uphole data by geostatistics. We tested approach two...

ABSTRACT Seismic tomography has been developed and applied for decades in seismological applications basic research purposes. During the last decade, large‐scale oil gas industry became standard as tomostatics velocity modelling pre‐stack depth migration. In this paper, I take a snapshot of some current industrial applications, quantifying practical aspects by yardsticks such data model size try to draw road map decade.

Recent advances in seismic acquisition and processing allowed enhancing significantly the imaging resolution, mainly by broadening signal bandwidth towards lower frequencies. So far, however, frequencies than a few Hz cannot be obtained standard surveys, this gap is normally filled estimating those components using velocity analysis. In paper, we propose similar approach for anelastic absorption, that is, merging low-frequency component given reflection tomography with high-frequency derived...