One of the major aspects of rock physics forward modeling is to predict seismic behavior at undrilled location using drilled well data. It is important to model the rock and fluid properties away from drilled wells to characterize the reservoir and investigate the root causes of different seismic responses. Using forward modeling technique, it is possible to explain the amplitude responses of present

In this work we tackle the challenge of quantitative estimation of reservoir dynamic property variations during a period of production, directly from 4D seismic data in the amplitude domain. We employ a deep neural network to invert 4D seismic amplitude maps to the simultaneous changes in pressure, water and gas saturations. The method is applied to a real field data case, where, as is common in such

Recently, the interest in PS‐converted waves has increased for several applications, such as sub‐basalt layer imaging, impedance estimates, and amplitude‐versus‐offset analysis. In this study, we consider the problem of separation of PP‐ and PS‐waves from pre‐stacked multicomponent seismic data in two‐dimensional isotropic medium. We aim to demonstrate that the finite‐offset common‐reflection‐surface

Frequency‐dependent amplitude variation with offset (AVO) offers an effective method for hydrocarbon detections and analysis of fluid flow during production of oil and natural gas within a fractured reservoir. An appropriate representation for the frequency dependency of seismic AVO signatures should incorporate influences of dispersive and attenuating properties of a reservoir and the layered structure

We propose the approach to 3‐D inversion of airborne electromagnetic data, which is intended for discovering subvertical bodies overlapped by essentially inhomogeneous conductive layers. The approach is based on the geometric inversion in which a geoelectrical medium is parameterized with the use of block structures. During the inversion, the coordinates of the borders between the blocks and the rows

Over the last two decades, scientists have introduced many ways to improve normal‐moveout velocity analysis by optimizing the resolution of the moveout velocity spectrum, a graph that displays a coherence value for every tested velocity travel‐time pair. Almost all these methods have failed to enhance resolution when faced with low‐fold common‐midpoint gathers, which might be caused by natural barriers

The conventional impedance inversion method ignores the attenuation effect, transmission loss and inter‐layers multiple waves; the smooth‐like regularization approach makes the corresponding impedance solution excessively smooth. The both fundamentally limit the resolution of impedance result and lead to the inadequate ability of boundary characterization. Therefore, a poststack impedance blocky inversion

Full waveform inversion (FWI) in transversely isotropic media with a vertical symmetry axis (VTI) provides an opportunity to better match the data at the near and far offsets. However, multiparameter FWI, in general, suffers from serious cycle‐skipping and trade‐off problems. Reflection waveform inversion (RWI) can help us recover a background model by projecting the residuals of reflections along

An inclusion model, based on the Kuster–Toksöz effective medium theory along with Gassmann theory, is tested to forward model velocities for fluid‐saturated rocks. A simulated annealing algorithm, along with the inclusion model, effectively inverts measured compressional velocity (VP) to achieve an effective pore aspect ratio at each depth in a depth variant manner, continuously along with depth. Early

Pore pressure prediction in shales undergoing compaction, including both mechanical and chemical processes, is customarily related to the mechanism referred to disequilibrium compaction. However, even when this mechanism is established and the normal compaction trend in sonic velocity, as a proxy for shale porosity, is well constrained, the pore pressure prediction may be in error because of the lithological

Seismic wave propagation through a fluid‐saturated poroelastic layer might be strongly affected by media heterogeneities. Via incorporating controlled laboratory simulation experiments, we extend previous studies of time‐lapse seismic effects to evaluate the wave scattering influence of the heterogeneous nature of porous permeable media and the associated amplification effects on 4D seismic response

Two‐dimensional elastic full waveform inversion was applied to two lines extracted from a spiral three‐dimensional vertical seismic profile data acquired in an oilfield offshore, Abu Dhabi, in the United Arab Emirates. The lines were selected to be parallel and perpendicular to the plane defined by the deviated borehole. The purpose of the inversion was to derive high‐resolution elastic properties

Downhole monitoring with fibre‐optic Distributed Accoustic Sensing (DAS) systems offers unprecedented spatial resolution. At the same time, costs are reduced since repeated wireline surveys can be replaced by the permanent installation of comparatively cheap fibre cables. However, the single component nature of fibre data requires novel approaches when designing a monitoring project such as cross‐well

Seismic images provided by reverse time migration can be contaminated by artefacts associated with the migration of multiples. Multiples can corrupt seismic images, producing both false positives, that is by focusing energy at unphysical interfaces, and false negatives, that is by destructively interfering with primaries. Multiple prediction/primary synthesis methods are usually designed to operate

In recent years, a variety of Marchenko methods for the attenuation of internal multiples has been developed. These methods have been extensively tested on 2D synthetic data and applied to 2D field data, but only little is known about their behaviour on 3D synthetic data and 3D field data. Particularly, it is not known whether Marchenko methods are sufficiently robust for sparse acquisition geometries

Depletion or injection into a reservoir implies stress changes and strains in the reservoir and its surroundings. This may lead to measurable time‐shifts for seismic waves propagating in the subsurface. To better understand the offset dependence of time‐shifts in the overburden, we have systematically quantified the time‐shifts of three different overburden shales in controlled laboratory tests. These

Modelling changes in elastic wave velocities in sediments and rocks as they undergo burial and uplift can reveal aspects of their burial history. This has implications in the petroleum risking procedures, as aspects such as hydrocarbon maturation and reservoir quality are key ingredients. Previous modelling for such a purpose assumes constant velocity and porosity during uplift after the cessation

Rock typing and flow unit detection are more challenging in clastic reservoirs with a uniform pore system. An integrated workflow based on well logs, inverted seismic data and rock physics models is proposed and developed to address such challenges. The proposed workflow supplies a plausible reservoir model for further investigation and adds extra information. Then, this workflow has been implemented

A number of deblending methods and workflows have been reported in the past decades to eliminate the source interference noise recorded during a simultaneous shooting acquisition. It is common that denoising algorithms focusing on optimizing coherency and weighting down/ignoring outliers can be considered as deblending tools. Such algorithms are not only enforcing coherency but also handling outliers

We propose a workflow of deblending methodology comprised of rank‐reduction filtering followed by a signal enhancing process. This methodology can be used to preserve coherent subsurface reflections and at the same time to remove incoherent and interference noise. In pseudo‐deblended data, the blending noise exhibits coherent events, whereas in any other data domain (i.e. common receiver, common midpoint

Based on the theory of tube wave propagation in a fluid‐filled borehole, this paper proposes a new method for detecting the integrity of pile foundation and overcomes some limitations of the existing pile integrity tests. The basic principle of detecting the pile integrity by the tube wave, testing equipment and concrete quality evaluation of piles are introduced. The feasibility of the tube wave detection

Seismic attenuation compensation is a spectrum‐broadening technique for enhancing the resolution of non‐stationary seismic data. The single‐trace attenuation compensation algorithms ignore the prior information that the seismic reflection events are generally continuous along seismic traces, thus, the compensated result may have poor spatial continuity and low signal‐to‐noise ratio. To address this

Seismoelectric coupling in an electric isotropic and elastic anisotropic medium is developed using a primary–secondary formulation. The anisotropy is of vertical transverse isotropic type and concerns only the poroelastic parameters. Based on our finite difference time domain algorithm, we solve the seismoelectric response to an explosive source. The seismic wavefields are computed as the primary field

Finite‐difference modeling with a cross‐rhombus stencil with high‐order accuracy in both spatial and temporal derivatives is a potential method for efficient seismic simulation. The finite‐difference coefficients determined by Taylor‐series expansion usually preserve the dispersion property in a limited wavenumber range and fixed angles of propagation. To construct the dispersion‐relationship‐preserving

In the framework of the Deep Electromagnetic Soundings for Mineral Exploration project, we conducted ground‐based long‐offset transient‐electromagnetic measurements in a former mining area in eastern Thuringia, Germany. The large‐scale survey resulted in an extensive dataset acquired with multiple high‐power transmitters and a high number of electric and magnetic field receivers. The recorded data

We present a new approach to enhancing weak prestack reflection signals without sacrificing higher frequencies. As a first step, we employ known multidimensional local stacking to obtain an approximate ‘model of the signal’. Guided by phase spectra from this model, we can detect very weak signals and make them visible and coherent by ‘repairing’ corrupted phase of original data. Both presented approaches

Deconvolution is an essential step for high‐resolution imaging in seismic data processing. The frequency and phase of the seismic wavelet change through time during wave propagation as a consequence of seismic absorption. Therefore, wavelet estimation is the most vital step of deconvolution, which plays the main role in seismic processing and inversion. Gabor deconvolution is an effective method to

Seismically derived amplitude‐versus‐angle attributes along with well constraints are the base inputs into inverting seismic into subsurface properties. Conditioning the common image gathers is a common workflow in quantitative inversion and leads to a more accurate inversion product due to the removal of post‐migration artefacts. Here, we apply a neural network to condition the post‐migration gathers

Although horizon interpretation is a routine task for building reservoir models and accurately estimating hydrocarbon production volumes, it is a labour‐intensive and protracted process. Hence, many scientists have worked to improve the horizon interpretation efficiency via auto‐picking algorithms. Nevertheless, the implementation of a classic auto‐tracking method becomes challenging when addressing

Inspired by the idea of the iterative time–frequency peak filtering, which applies time–frequency peak filtering several times to improve the ability of random noise reduction, this article proposes a new cascading filter implemented using mathematic morphological filtering and the time–frequency peak filtering, which we call here morphological time–frequency peak filtering for convenience. This new

In glacial studies, properties such as glacier thickness and the basement permeability and porosity are key to understand the hydrological and mechanical behaviour of the system. The seismoelectric method could potentially be used to determine key properties of glacial environments. Here we analytically model the generation of seismic and seismoelectric signals by means of a shear horizontal seismic

Reduction to pole and other transformations of total field magnetic intensity data are often challenging to perform at low magnetic latitudes, when remanent magnetization exists, and when large topographic relief exists. Several studies have suggested the use of inversion‐based equivalent source methods for performing such transformations under those complicating factors. However, there has been little

Tunnel forward geological prediction is indispensable to tunnel construction. The transient electromagnetic method is widely used in the field of tunnel forward geological prediction. A small fixed‐loop transient electromagnetic method adapted to the limited space of a tunnel face is proposed for tunnel forward geological prediction for the first time. This method makes use of a large number of non‐central

Acoustic inversion in one‐dimension gives impedance as a function of travel time. Inverting the reflection response is a linear problem. Recursive methods, from top to bottom or vice versa, are known and use a fundamental wave field that is computed from the reflection response. An integral over the solution to the Marchenko equation, on the other hand, retrieves the impedance at any vertical travel

In multi‐parameter ray‐based anisotropic migration/inversion, it is essential that we have an understanding of the scattering mechanism corresponding to parameter perturbations. Because the complex nonlinearity in the anisotropic inversion problem is intractable, the construction of true‐amplitude linearized migration/inversion procedures is needed and important. By using the acoustic medium assumption

Traditional coherence algorithms are often based on the assumption that seismic traces are stationary and Gaussian. However, seismic traces are actually non‐stationary and non‐Gaussian. A constant time window and the canonical correlation analysis in traditional coherence algorithms are not optimal for non‐stationary seismic traces and cannot describe the similarity between adjacent seismic traces

Two seismic modelling approaches, that is, two‐dimensional pre‐stack elastic finite‐difference and one‐dimensional convolution methods, are compared in a modelling exercise over the fluid‐flow simulation model of a producing deep‐water turbidite sandstone reservoir in the West of Shetland Basin. If the appropriate parameterization for one‐dimensional convolution is used, the differences in three‐dimensional

A magnetotelluric acquisition and modelling campaign, comprising 400 full tensor soundings, was carried out in the Sub‐Andean Foothills in the area located south of Santa Cruz de la Sierra, Bolivia. The objective of the survey was to improve the imaging of the Paleozoic section and provide insight to the overall structure of the Devonian Silurian complex. The acquired data were inverted assuming both

In near‐surface transient electromagnetic studies, it is desirable to measure the transient response starting from the earliest possible time. This requires the current in the transmitter loop to be switched off quickly, which necessitates working with a low transmitter current. As for deep‐target transient electromagnetic studies, the transmitter current is as high as possible. The transmitter current's

We propose an optimized method to compute travel times for seismic inversion problems. It is a hybrid method combining several approaches to deal with travel time computation accuracy in unstructured meshes based on tetrahedral elementary cells. As in the linear travel time interpolation method, the proposed approach computes travel times using seismic ray paths. The method operates in two sequential

We investigate the seismoelectric/electroseismic wavefields excited by a point source in an air/seawater/three‐layered porous medium configuration containing a hydrocarbon layer. The results show that if an explosive source for excitation is used, receivers at seafloor can record the coseismic electromagnetic fields accompanying the P, S, fluid acoustic waves and the interface responses converted from

Random noise attenuation utilizing predictive filtering achieves great performance in denoising seismic data. Conventional predictive filtering methods are based on fixed filter operators and neglect the complexity of structures. In this way, the denoised data cannot meet the requirement of balancing the signal preservation and noise removal. In this study, we proposed a structural complexity‐guided

Conventional Kirchhoff prestack time migration based on the hyperbolic moveout can cause ambiguity in laterally inhomogeneous media, because the root mean square velocity corresponds to a one‐dimensional model under the horizontal layer assumption; it does not include the lateral variations. The shot/receiver configuration with different offsets and azimuths should adopt different migration velocities

Tight oil siltstones are rocks with complex structure at pore scale and are characterized by low porosity and low permeability at macroscale. The production of tight oil siltstone reservoirs can be increased by hydraulic fracturing. For optimal fracking results, it is desirable to map the ability to fracture based on seismic data prior to fracturing. Brittleness is currently thought to be a key parameter

Migration velocity analysis is a method devoted to the evaluation of both reflectivity and background velocity models, associated with the high and low wavenumber components of the model, respectively. Inversion velocity analysis is one of its improved versions, leading to more stable background velocity updates. Still, the impact of the user parameters should be understood for an optimal update of

The study examines the Egyptian Red Sea shelf and throws more light on the structural set‐up and tectonics controlling the general framework of the area and nature of the crust. Herein, an integrated study using gravity and magnetic data with the available seismic reflection lines and wells information was carried out along the offshore area. The Bouguer and reduced‐to‐pole aeromagnetic maps were processed

The conventional reverse time migration of ground‐penetrating radar data is implemented with the two‐way wave equation. The cross‐correlation result contains low‐frequency noise and false images caused by improper wave paths. To eliminate low‐frequency noise and improve the quality of the migration image, we propose to separate the left‐up‐going, left‐down‐going, right‐up‐going and right‐down‐going

In this paper, we develop a general approach to integrating petrophysical models in three‐dimensional seismic full‐waveform inversion based on the Gramian constraints. In the framework of this approach, we present an example of the frequency‐domain P‐wave velocity inversion guided by an electrical conductivity model. In order to introduce a coupling between the two models, we minimize the corresponding

Some key geologic data can only be obtained from wells. This article provides original technology concerning the geological mapping validation of complex anomalous zones based on information obtained from irregular or sparse drilling. Only complex non‐unique cases of geologic characteristics delineation (i.e. characterized by multiple solutions) are considered here. Representative groups of multiple

Although Genetic Algorithms have found many successful applications in the field of exploration geophysics, the convergence speed remains a big challenge as Genetic Algorithms usually require a huge amount of fitness function evaluations. In this paper, we propose an efficiency‐improved Genetic Algorithm, which has both a good global search capability and a good local search capability, and is also

An improved interpolation scheme is presented for 2.5‐dimensional marine controlled‐source electromagnetic forward modelling. For the marine controlled‐source electromagnetic method, due to the resistivity contrast between the seawater and seafloor sedimentary layers, it is difficult to compute the electromagnetic fields accurately at receivers, which are usually located at the seafloor. In this study

A three‐dimensional finite‐element time‐domain forward‐modelling algorithm is developed to simulate transient electromagnetics excited by grounded‐wire sources. The main advantage of this finite‐element time‐domain algorithm is that full transmitting‐current waveforms and complex‐shaped sources resulting from topography can be directly dealt with in this algorithm. The models used to test this algorithm

As the application of high‐density high‐efficiency acquisition technology becomes more and more wide, the areas with complex surface conditions gradually become target exploration areas, and the first‐break picking work of massive low signal‐to‐noise ratio data is a big challenge. The traditional method spends a lot of manpower and time to interactively pick first breaks, a large amount of interactive

This paper deals with the design, acquisition and processing of vertical seismic profiling data collected in 2016 at the directional Thônex‐01 geothermal well, drilled in 1993 in the Geneva Canton (Switzerland). The aim of the study was to obtain additional information from existing‐abandoned well for downhole geophysical characterization of potential geothermal reservoirs in the Geneva area. The main

Reverse time migration is an advanced seismic migration imaging method. When the source wavefield and the receiver wavefield are cross‐correlated, the cross‐correlations of direct arrivals, backscattered waves and overturned waves will produce a lot of low‐frequency noise, which will mask the final imaging results. Laplacian filtering, as a common method to suppress low‐frequency noise, can adapt to

The current time‐lapse practice is to exactly repeat well‐sampled acquisition geometries to mitigate acquisition effects on the time‐lapse differences. In order to relax the rigid requirements on acquisition effects, we propose simultaneous joint migration inversion as an effective time‐lapse tool for reservoir monitoring, which combines a joint time‐lapse data processing strategy with the joint migration

High‐speed train seismology has come into being recently. This new kind of seismology uses a high‐speed train as a repeatable moving seismic source. Therefore, Green's function for a moving source is needed to make theoretical studies of the high‐speed train seismology. Green's function for three‐dimensional elastic wave equation with a moving point source on the free surface is derived. It involves

In this paper, we develop a new nearly analytic symplectic partitioned Runge–Kutta method based on locally one‐dimensional technique for numerically solving two‐dimensional acoustic wave equations. We first split two‐dimensional acoustic wave equation into the local one‐dimensional equations and transform each of the split equations into a Hamiltonian system. Then, we use both a nearly analytic discrete

Wave equation–based migration velocity analysis techniques aim to construct a kinematically accurate velocity model for imaging or as an initial model for full waveform inversion applications. The most popular wave equation–based migration velocity analysis method is differential semblance optimization, where the velocity model is iteratively updated by minimizing the unfocused energy in an extended

Logistic regression, neural networks and support vector machines are tested for their effectiveness in isolating surface waves in seismic shot records. To distinguish surface waves from other arrivals, we train the algorithms on three distinguishing features of surface‐wave dispersion curves in the domain: spectrum coherency of the trace's magnitude spectrum, local dip and the frequency range for a