Mapping full seismic waveforms to vertical velocity pro. Seismic inversion describes the theory and practice of inverting seismic data for the subsurface rock properties. The primary application is for inverting reflection andor transmission data. We present a waveequation inversion method that inverts skeletonized data for the subsurface velocity model. Seismic inversion is a technique that has been in use by geophysicists for almost forty years. There are at least three fundamental issues to be solved simultaneously. Seismic waveform inversion by stochastic optimization. This inversion, called seismic inversion for reservoir characterization, reads between the lines, or between reflecting interfaces, to produce detailed models of rock properties. In exploration geophysics, seismic imaging has been in use for over 20 yr, where inversion proceeds mainly from traveltime baig et al. Developments, workflow, and case studies huyen bui, arthur weglein, sunil kumar, scott singleton, oswaldo davogustto cataldo, malleswar yenugu, samarjit chakraborty, and ramses meza.
The ultimate goal of such an approach is to dramatically reduce the computational cost involved in evaluating the misfit. This allows us to integrate well data into the inversion and to simplify the mapping by using the regularity of active seismic acquisition. Interferometricdaylight seismic imaging schuster 2004. It is a valuable resource for seismic processing practitioners and theoretical geophysicists. Seismic inversion methods and some of their constraints.
Velocity model building from seismic reflection data by full. The basic principle of such methods is to randomly draw a batch of realizations of a given misfit function and goes back to the 1950s. Seismic inversion aims to reconstruct a quantitative model of the earth subsurface, by solving an inverse problem based on seismic measurements. Fullwaveform inversion of shortoffset, bandlimited seismic data in. The input to the autoencoder is the recorded common shot gathers, and the implicit function theorem is. A profitable development of an oil or gas field starts with a good understanding of the subsurface as a basis for efficient and successful field management. Introduction to seismic inversion seismic inversion.
Again, notice the excellent delineation of the gas sand. An introduction to full waveform inversion isterre. The objective of seismic inversion is to convert reflectivity data interface properties to layer properties. We explore the use of stochastic optimization methods for seismic waveform inversion.
When iterated, this method corresponds to iteratively reweighted least squares with a simulated l 1 norm for vector p trad etal. Well logs are first conditioned and edited to ensure there is a suitable relationship. Since full waveform modelling is signi cantly nonlinear with respect to velocities, monte carlo. Thickness and porosity are fairly easy to predict, and some distinction may be made between gassaturated reservoir and wet reservoir.
Quality control and preconditioning of the input data. Inversion transforms seismic reflection data into rock and fluid properties. Stochastic vs deterministic pre stack inversion methods. The tomogram is presented graphically as a two or threedimensional 2d or 3d grid of pixels, in which each pixel contains the model parameter of interest, such as the velocity value or its reciprocal value known as slowness. For both deterministic and stochastic inversion, the seismic amplitudes control intermediate frequencies within the seismic bandwidth. Full waveform inversion fwi is a high resolution seismic. Well logs are first conditioned and edited to ensure there is a suitable relationship between impedance logs and the desired properties. Seismic inversion is essentially a very simple procedure. Inversion was used to improve the prediction of reservoir properties from the 3d seismic. Seismic inversion by newtonian machine learning abstract. This book describes the theory and practice of inverting seismic data for the subsurface rock properties of the earth. According to bayes theorem, pmjd obs pd obsjmpm pd obs 1 where pd. Bayesian methods update a prior probability density function pdf pm with new information from the data to produce a probability distribution of model parameters post inversion, which is often called a posterior pdf, written as pmjd obs.
Preface this book describes the theory and practice of inverting seismic data for the subsurface rock properties of the earth. Cgg geoconsulting has developed a 4d inversion workflow extending the 3d simultaneous elastic inversion to joint multivintage inversion, with simultaneous inversion of all angle stacks for base and monitor surveys. Seismic inversion conventional seismic impedance inversion and advanced seismic inversion techniques. Data considerations for inversion prestack andor poststack time migrated seismic data well data conditioning and editing is necessary wavelet estimation required for all modern inversion approachesdeterministicstatistical low frequency trend absolute acoustic impedance contains a low frequency trend that must be obtained usually from well control or. To combine the multiscale fwi and phase inversion methods, sun and schuster. Some other alternatives are spaceadaptive and discrete spike inversions. There are also numerous other impedance methods used in avo, such as the elastic impedance ei and extended.
Inversion in itself means to undo an operation,but here it represents the transformation of a seismic amplitude cube into an acoustic or elastic impedance cube. The skeletonized representation of the seismic traces consists of the lowrank latentspace variables predicted by a welltrained autoencoder neural network. The viability of these simulations is predicated on the availability of earth models of suf. There are several ways to achieve this objective, as will be shown later on. The input to the autoencoder is the recorded common shot gathers, and the implicit function theorem is used to determine the. Pdf seismic inversion by newtonian machine learning. Full waveform inversion for seismic velocity and anelastic. Interferometric seismic imaging is defined to be any algorithm that inverts correlated seismic data for the reflectivity or source distribution. Crains petrophysical handbook seismic inversion basics. The primary application is for inverting reflection andor transmission data from engineering or exploration surveys, but the methods described also can be used for earthquake studies. A newtoncg method for largescale threedimensional elastic. In stochastic inversion, the vertical variogram model controls the high frequencies. To determine elastic parameters, the reflectivity from avo effects must be inverted.
Cnns are trained to map the seismic data directly into velocity logs. Schuster department of earth science and engineering, king abdullah university of science and technology, thuwal, saudi arabia, 239556900. Schuster, describes the theory and practice of inverting seismic data for the subsurface rock properties of the earth. His geophysical lab is equipped with stateoftheart seismographs for 624 channel recording and a 72channel resistivity array for both exploration. Mapping full seismic waveforms to vertical velocity pro les. Early inversion techniques transformed the seismic data into pimpedance the product of density and pwave velocity, from which we were able to make predictions about lithology and porosity. The background image on the far right is an actual seismic section. As we will show in our data examples, this reduction in resolution is modest and often quite tolerable for multiscale phase inversion. Schuster, and sia hassanzadeh abstract a hybrid waveequation traveltime and waveform inversion method is presented that reconstructs the interwell velocity distribution from crosshole seismic data. Schuster seismic inversion describes the theory and practice of inverting seismic data for the subsurface rock proper ties of the earth.
Seismic inversion the best tool for reservoir characterization. In other words, if we had drilled and logged wells at the cmps, what. It relates the different models of seismic propagation, reflection, and imaging providing links to reflectivitybased imaging and to nonlinear seismic inversion. There is a bright future for the use of geophysics but it requires that inversion be applied with care and understanding. Ebook introduction to seismic inversion methods as pdf. April 25, 2019 seismic inversion by newtonian machine learning running head. We apply coherency enhancement to a timemigrated seismic image from a gulf of mexico dataset claerbout,2005,showninfigure1. Seismic inversion compressive leastsquares migration with onthefly fourier transforms philipp a. Apr 24, 2019 we present a waveequation inversion method that inverts skeletonized data for the subsurface velocity model. For simplicity, the following discussion describes only modelbased inversion. In the second poststack inversion paper, singh proposes a technique for performing poststack seismic inversion in the depth domain. Society of exploration geophysicists releases seismic inversion by gerard t. The primary application is for inverting reflection. The principle objective of seismic inversion is to transform seismic reflection data into a quantitative rock property, descriptive of the reservoir.
Witte, mathias louboutin, fabio luporini, gerard j. Introduction to seismic inversion methods top results of your surfing introduction to seismic inversion methods start download portable document format pdf and ebooks electronic books free online rating news 20162017 is books that can provide inspiration, insight, knowledge to the reader. The presented approach uses gathers of neighboring common midpoints cmps for the estimation of a vertical velocity log. Corner seismic inversion successfully predicts interpreters. Algorithm and methodology for application to the salt structure inversion g. Welltoseismic match, zerophasing of data in zone of interest and extraction of the wavelet. As examples, we show that ii can image reflectivity distributions by migrating ghost reflections in passive seismic data and generalizes the receiver. Seismic inversion by newtonian machine learning yuqing chen and gerard t. Seismic inversion, or tomography, is the procedure for reconstructing earth properties from seismic data. For all inversion methods, the prior model is constructed by interpolating filtered logs, and controls low frequencies.
This book describes the theory and practice of inverting seismic data for the subsurface rock properties. Anyone using inversion algorithms, or interpreting resultant images, must be familiar with the basic principles. Used to image and analyze reservoir changes in pressure and fluid saturation to optimize hydrocarbon recovery. Seismic waveform inversion by stochastic optimization tristan van leeuwen, aleksandr aravkin and felix j.
Our smooth inversion tomographic method is based on physically realistic modeling of first break propagation for pwave and swave surveys. Tulsa, ok, 12 july 2017 seismic inversion, by gerard t. Fullwaveform inversion of shortoffset, bandlimited seismic data in the alboran. Seismic inversion is a somewhat confusing expression. This inversion procedure leads us to a seismic volume that portrays layer properties in terms of impedance rather than interface characteristics, and assumes that the reflecting horizons have already been properly migrated to their appropriate positions.
Inversion includes both seismic field data and well data, where well data serves to add the high frequency below the seismic band and to constrain the inversion. The position of the crossplot zones on the seismic stack of figure 2, gas zone red. This scheme overcomes the issue of wavelet estimation and convolution in the depth domain by using a. Schuster, waveequation traveltime inversion, geophysics 56. Chen1 1school of earth sciences, zhejiang university, hangzhou, china, 2modeling and imaging laboratory, earth and planetary sciences, university of california, santa cruz, ca, usa.
Other views of the earth using seismic data are shown in figure 1. Acoustic waveequation traveltime and waveform inversion. Seismic inversion geoscienceworld books geoscienceworld. Note that in the strict sense, the inversion described for migration or imaging. Because seismic wavelets are bandlimited and seismic data are finite and inaccurate, there exist an infinite number of reflectivity series that can fit the data equally well. Pdf seismic inversion methods and some of their constraints. Basics of seismic imaging king abdullah university of.
Seismic inversion algorithms span the range between two extremes. Seismic inversion by gerard thomas schuster, 9781560803416, available at book depository with free delivery worldwide. Seismic inversion investigations in geophysics seg library. The wide spread strategy of seismic imaging, the single. Velocity model building from seismic reflection data by. Acoustic waveequation traveltime and waveform inversion of crosshole seismic data changxi zhou, wenying cai, yi gerard t. In its most simple form, acoustic impedance logs are computed at each cmp.
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