In this study, we show how stochastic inversion can improve the. An indicator cokriging deutsch and journel, 1998 is first applied to take into account well data and geological a priori information and to obtain the ccdf of the acoustic impedance ai at each grid node of the model. Seismic inversion geoscienceworld books geoscienceworld. Prediction of reservoir properties using seismic stochastic inversion. Colored inversion is a robust seismic reservoir characterisation tool, which provides band limited impedance data from seismic reflectivities lancaster and whitcombe, 2000. A strategy for nonlinear elastic inversion of seismic. Interwell seismic inversion and reservoir characterization. Seismic inversion has been used for several decades in the petroleum industry, both for exploration and production purposes. We explore the use of stochastic optimization methods for seismic waveform inversion. Stochastic seismic inversion is complementary to deterministic inversion. Pdf stochastic and deterministic seismic inversion methods for. Acoustic impedance inversion of vintage seismic data over a. Seismic waveform inversion by stochastic optimization tristan van leeuwen, aleksandr aravkin and felix j.
Pdf results from a typical poststack or prestack seismic inversion are bandlimited primarily due to missing low and high frequencies in the. Recent progress in numerical methods and computer science allows us today to simulate the propagation of seismic waves through realistically heterogeneous earth models with unprecedented accuracy. In the second poststack inversion paper, singh proposes a technique for performing poststack seismic inversion in the depth domain. The seismic inversion can be achieved by several methods, which can be divided into two main groups. A discussion is given concerning the development of methods for obtaining an accurate representation of the forward elastostatic problem of describing the processes which accompany faulting. 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. Glinskyb acsiro division of petroleum resources, ian wark laboratory, bayview ave. The dataset used here to compare deterministic and sto chastic seismic inversion is the stratton field 3d seismic and well log data package, prepared by the. Seismic imaging and inversion application of linear inverse theory extracting information from seismic data requires knowledge of seismic wave propagation and re. Capability of the stochastic seismic inversion in detecting the thin beds. In stochastic inversion, the vertical variogram model controls the high frequencies. For all inversion methods, the prior model is constructed by interpolating filtered logs, and controls low frequencies. A broad meaning of seismic inversion commonly referred to as elastic inversion, is the grand scheme of estimating elastic parameters directly from observed data. Stochastic vs deterministic prestack inversion methods cgg.
This intermediate trend 212 hz separates out itself. Stochastic inversion of facies from seismic data based on. Stochastic inversion of seismic pp and ps data for. Welltoseismic match, zerophasing of data in zone of interest and extraction of the wavelet. Seismic inversion the best tool for reservoir characterization. We address the solution of largescale statistical inverse problems in the framework of bayesian inference.
The stochastic seismic inversion proposed in this study is an implementation of ensemble kalman filter enkf. Full waveform inversion of seismic data for a viscoelastic. Pdf stochastic and deterministic seismic inversion methods. The second approach is modelbased inversion technique russell and hampson, 1991. Statistical rock physics rock physics link seismic response and reservoir properties well log, geology extend the available data to generate training data for the classification system. To determine elastic parameters, the reflectivity from avo effects must be inverted. Low frequency modeling and its impact on seismic inversion. In stochastic inversion, the leastsquares inversion method is extended by formulating the problem using a gaussian or log gaussian posterior probability density function, or pdf tarantola, 1987. Typically, a reflection coefficient series from a well within the boundaries of the seismic survey is used to estimate the wavelet phase and frequency. Here are some of the papers that we have published on seismic inversion. Quantifying shallow seismic anomalies, published in aapg explorer. Acoustic impedance from a stochastic inversion of 3d seismic data is used to constrain the. The seismic inversion method that is presented in this work is classified as a deterministic inversion method russell, 1988.
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. In geostatistical terms the solution is to compute conditional simulations of the seismic inversion and analyse the resulting impedance realisations. Hamood, there are basically two types of inversion of data. 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. Results from a typical poststack or prestack seismic inversion are bandlimited primarily due to missing low. Figure 6 shows example of the seismic towell tie near the water source well 1f11129452w5, at which a very good correlation is obtained 0. Stochastic seismic inversion based on an improved local. Probabilistic reservoir characterization via seismic. Although many recent papers have demonstrated some advantages of geostatistical methods over deterministic methods francis, 2005. The position of the crossplot zones on the seismic stack of figure 2, gas zone red. Describing seismic sources there is a wide variety of seismic sources, both natural and manmade. In a seismic inversion the original reflectivity data, as typically recorded routinely, is converted from an interface property i.
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. The objective of seismic inversion is to convert reflectivity data interface properties to layer properties. Overview of momenttensor inversion of microseismic events. Seismic inversion poststack seismic resolution inversion. Capability of the stochastic seismic inversion in detecting the thin. A complete introduction to enkf can be found in evensen 2007. Nevertheless, in practice, applications of inversion methods can be grouped in two categories data modeling and earth modeling. The work flow illustrated in this poster will be for poststack data seismic inversion. In its most simple form, acoustic impedance logs are computed at each cmp. Seismic inversion and synthetic sonic logs calibration of seismic attributes to ground truth is still an emerging science. These methods minimize an objective function, which is usually a measure. There are also numerous other impedance methods used in avo, such as the elastic impedance ei and extended. Used to image and analyze reservoir changes in pressure and fluid saturation to optimize hydrocarbon recovery. Pdf stochastic seismic inversion for static reservoir modeling.
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. For this reason, seismic inversion is an important processing tool. Wells logs, core analyses, and production logs constitute the hard data. There is a bright future for the use of geophysics but it requires that inversion be applied with care and understanding.
For both deterministic and stochastic inversion, the seismic amplitudes control intermediate frequencies within the seismic bandwidth. Seismic inversion is essentially a very simple procedure. Full waveform tomography is a tomographic technique that takes advantage of numerical solutions of the elastic wave equation. Stochastic vs deterministic pre stack inversion methods. Largescale inverse problems from the discrete problems obtai. Building more robust lowfrequency models for seismic. Sip seismic inversion gives you a high resolution layered geological image of the earth in 2d, 3d or 4d. During this time, seismic inversion methods have progressed from the initial recursive inversion method to the present plethora of methods and software packages available to transform bandlimited seismic traces to impedance traces. Enfk can perform linear and nonlinear stochastic inversion. Such broadband data may considerably augment existing bands and provide invaluable information for producing highquality subsurface images. We are especially interested in the effect of lowfrequencies on seismic analysis. Well logs are first conditioned and edited to ensure there is a suitable relationship between impedance logs and the desired properties.
We have introduced one more category as the intermediate trend. Colop operator design for colored inversion, spectral blueing and spectral whitening. Seismic inversion is now commonly used on poststack and prestack seismic data for estimating rock properties used in reservoir characterization. The first is bandlimited inversion, in which a scaled relative impedance from the seismic data is mixed with a low frequency element from the model. Pdf stochastick seismic inversion abdelhamid zeffanine. Inversion transforms seismic reflection data into rock and fluid properties. Again, notice the excellent delineation of the gas sand. Crains petrophysical handbook seismic inversion basics. The ultimate goal of such an approach is to dramatically reduce the computational cost involved in evaluating the misfit. Stochastic and deterministic seismic inversion methods for. Limitations of deterministic inversion inversion techniques to estimate impedance from seismic have been available to. Stochastic inversion of facies from seismic data based on sequential simulations and probability perturbation method dario grana 1, tapan mukerji2, jack dvorkin, and gary mavko abstract we presented a new methodology for seismic reservoir char.
Limitations of deterministic and advantages of stochastic. The current emphasis in seismic stratigraphy has this process of wavelet extraction, followed by the focussed on velocity inversion and the generation of derivation of the reflectivity sequence, allows the the pseudoacoustic log from the seismic trace. Pdf capability of the stochastic seismic inversion in. Seismic acoustic impedance inversion in reservoir characterization utilizing gocad by steven clawson and haizui hairay meng, presented at the 2000 gocad users meeting introduction workflows for utilizing seismic data inverted to acoustic impedance data. Our seismic inversion workflow, illustrated opposite, is based on a phased approach. In order to characterize hydrocarbons reservoirs, different results of seismic inversion methods can be in use, like deterministic andor stochastic inversion results. Robinson, 2001, the latter can still provide geologically plausible acoustic impedance. Stochastic seismic inversion using both waveform and. In the development of this study, 3d seismic data and well data from the norne. Full seismic waveform modelling and inversion springerlink. The correlation coefficients associated with the wells used in the inversion are shown in figure 5. Stochastic inversion methods the latest inversion techniques using stochastic methods will be described. 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.
This allows us to sample various scenarios from the pdf using the monte carlo mc or markov chain monte carlo mcmc approach. All modern seismic inversion methods require seismic data and a wavelet estimated from the data. The background image on the far right is an actual seismic section. The stochastic methods of seismic inversion are based on the sampling of the probability density functions.
A critical factor to achieving good inversion results is the seismic towell tie. Processing and seismic inversion of the intrepid seismic. While seismic migration is aimed at imaging the reflectors or the interfaces at their correct subsurface locations, seismic inversion attempts to estimate elastic and flow properties of the layers. Conventional practice was to delineate the reservoir using post stack seismic data while prestack seismic data was completely ignored. Stochastic seismic inversion is performed integrating well and seismic data to build reservoir property model. In the cases of natural tectonic and induced seismicity, the sources often are assumed to be. The inversion process can be applied to poststack or prestack data. Seismic waveform inversion by stochastic optimization. Geometric theory of inversion and seismic imaging august lau and chuan yin june 2, 2015 abstract the goal of inversion is to estimate the model which generates the data of observations with a speci c modeling equation. Stochastic and deterministic seismic inversion methods for thinbed resolution view the table of contents for this issue, or go to the journal homepage for more 2012 j.
The geosi method that i will discuss today combines both a gaussian pdf and. This approach reduces the computer memory requirements to the point where computations are practical. It handles a large range of seismic data in dedicated workflows from data conditioning to quantitative property estimation. A method is suggested by which a more complicated and arbitrary static dislocation function could be approximated with the formulations derived for simple dislocation sources. Stochastic and deterministic seismic inversion methods for thinbed. Subsequent phases depend on completion of previous phases of work. Probabilistic reservoir characterization via seismic elastic inversion in east andaman basin mahendra kishore1, pritam jha2, dino ros2, and alfonso iunio marini3. This scheme overcomes the issue of wavelet estimation and convolution in the depth domain by using a. Poststack seismic inversion, developed in the 1970s, reverses the forward. Enhancing the quality of seismic impedance data, published in aapg explorer.
By using this constitutive relation and the adjoint state technique, we propose a new formulation for the viscoelastic seismic inverse problem. Figure 6 shows example of the seismictowell tie near the water source well 1f11129452w5, at which a very good correlation is obtained 0. These include explosions, implosions, shear failure, tensile failure, and single forces. This also has the advantage of allowing the uncertainty nonuniqueness in seismic inversion to be investigated. The markov chain monte carlo mcmc method is the most popular approach for sampling the posterior probability distribution that describes the solution of the statistical inverse problem. Examples of 3d seismic inversion, particularly model building, will be illustrated using the stratton data set. Then they used the inversion seismic attributes to extend the facies classification away from the wells to the whole seismic. This is especially true of the large threedimensional surveys that are now routinely being acquired. A critical factor to achieving good inversion results is the seismictowell tie.
Impedance inversion has been carried out in the time domain for the last four decades. An example of a poststack seismic resolution inversion technique is the constrained sparsespike inversion cssi. Colop operator design for colored inversion, spectral. Seismic acoustic impedance inversion in reservoir characte. The old and the new in seismic inversion cseg recorder. For illustration, this full viscoelastic waveform inversion has been applied for a numerical experiment.
Stochastic seismic inversion is one method that can provide the vertical resolution sufficient to generate detailed 3d reservoir property models. Low frequency modeling and its impact on seismic inversion data. Removing the background trend from the data would reveal out the anomalous geobodies. Seismic resolution is a function of the frequency of the recorded seismic wavefield and the velocity of the medium.
The methodology we proposed can integrate the geological a priori information and their spatial correlations in seismic inversion. Consequently, seismic inversion and multiattribute analysis for rock characterisation is at present limited to instances where a minimum set of conditions is fulfilled. Low frequency modeling and its impact on seismic inversion data any deviation from this shale trend is an anomalous signature. Basics of seismic imaging king abdullah university of. Reservoir characterization using avo and seismic inversion techniques abhinav kumar dubey, iit kharagpur summary reservoir characterization is one of the most important components of seismic data interpretation. Building more robust lowfrequency models for seismic impedance. Event locations and magnitudes give limited insight into the processes that control the growth and dynamics of hydraulic fractures. Pdf results from a typical poststack or prestack seismic inversion are band limited primarily due to missing low and high frequencies in the. Generally, the stochastic inversion methods use broadband starting models drawn from welllogbased a priori distribution of the model space and apply a globalsearch method for seismic data fitting torresverdin et al1999, francis 2006a, 2006b, srivastava and sen 2010.
The necessity of developing stochastic approaches will be emphasised, and in particular the link with geostatistics will be made. We achieve this by combining seismic data, well log data, horizon surfaces and velocities from time or depth imaging. A possible workflow for performing a modelbased seismic inversion consists of loading three types of data. Interwell is a seismic inversion and characterization software for reservoir and exploration geophysicists, available in linux and windows environments. Our understanding of reservoir behaviour can be enhanced by considering the seismic moment tensor representations of these events, which serve as a direct snapshot of the instantaneous deformation of the surrounding rock by the seismicity. Acoustic impedance inversion of vintage seismic data over.
Pdf seismic inversion methods and some of their constraints. Seismic inversion is a technique that has been in use by geophysicists for over forty years. Accurate wavelet estimation is critical to the success of any seismic inversion. Pdf stochastic and deterministic seismic inversion. Limitations of deterministic inversion inversion techniques to estimate impedance from seismic have been available to geophysicists for over twenty years. In other words, if we had drilled and logged wells at the cmps, what. Lowfrequencies have a great effect on seismic inversion and may considerably broaden the.
Other views of the earth using seismic data are shown in figure 1. Seismic inversion is used to infer reservoir features such as porosity and fluid saturation from seismic data. However, the advantage of the seismic method is that coverage can be made over large areas of the earths surface. Pdf on nov 1, 2017, s k mekap and others published stochastic seismic inversion for static reservoir modeling find, read and cite all the. The principle objective of seismic inversion is to transform seismic reflection data into a quantitative rock property, descriptive of the reservoir. Both stochastic and deterministic inversion methods utilize the following convolution model. Anyone using inversion algorithms, or interpreting resultant images, must be familiar with the basic principles. Seismic inversion a work flow for modelbased inversion.
Matching operator that optimally converts input seismic to sparsespike inversion. Processing and seismic inversion of the intrepid seismic line. If it has to be carried out in depth, there are a few questions that come to mind what is so different about carrying out inversion in depth rather than time, how does it help, and if it were. Reservoir characterization using avo and seismic inversion. This book describes the theory and practice of inverting seismic data for the subsurface rock properties of the earth. Deterministic inversion is analogous to kriging which has the same limitations. Quality control and preconditioning of the input data. Preconditioning of seismic data prior to impedance inversion, published in aapg explorer. Deterministic inversion is a method whereby an observed data set and some known basic model generally a set of ordinary or partial differential e. The inversion results in acoustic impedance ai, which is the product of rock.
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