This type of processing facilitates the interpretation of meaningful geological and petrophysical boundaries on the reflection data veeken et al. Pdf neurobayesian facies inversion of prestack seismic. Summary in this paper, we present a new approach to the simultaneous prestack inversion of pp and, optionally, ps angle gathers for the estimation of pimpedance, simpedance and density. Prestack inversion transforms seismic angle or offset data into pimpedance, simpedance and density volumes through integration of the seismic angleoffset gathers, well data and a basic stratigraphic interpretation. You can do poststack inversion on any kind of stack. Final elasticparameter models optimally reproduce the input seismic, as this is part of the seismic inversion. Prestack seismic data inversion for shale gas reservoir characterization in china gang yu. Post stack seismic inversion, developed in the 1970s, reverses the forward modeling. Final elasticparameter models optimally reproduce the input seismic, as this is part of the seismic inversion optimization. Rich reservoir parameter information can be obtained through inversion of prestack data. This study describes a workflow in which the prestack seismic inversion is framed as a deep learning problem.
A convolutional neural network cnn is trained and tested on a set of. Pitfalls in prestack inversion of merged seismic surveys. Other combinations of elastic parameters such as pimpedance, vpvs ratio and density are equally possible. The seismic inversion is a process usually affected by the noise and measurement errors in the measured data. Poststack seismic inversion, developed in the 1970s, reverses the forward modeling. Summary the similarity between seismic inversion and machine learning lies in the fact that both are essentially optimization problems.
The concept is intended to arrive at the same point as the workflow provided above. Comparison of an inversion run in the native depth domain with one run in the traditional time domain. The method computes the probabilities for different lithologyfluid classes from seismic data and geological knowledge. This is a generalization, to prestack seismic data, of basic principles of geostatistical inversion with a global. A comparison of porosity estimates obtained using post, partial, and prestack seismic inversion methods. Seismic exploration is an oil exploration method by utilizing seismic information. Use of prestack data for quantitative analysis of hydrocarbon reservoirs has gained popularity over the past decades. Most seismic surveys provide images using data that have been stacked. Improving the quality of prestack inversion by prestack. Improved spatial constraints for seismic impedance inversion. Neurobayesian facies inversion of prestack seismic data from a carbonate reservoir in iran. This in turn requires, strictly, an estimated earth model in depth that.
The multitrace simultaneous prestack inversion of lci and sci has been successfully applied to 2d seismic data of coal bed. Different methods of seismic inversion, including deterministic and stochastic. Heres a thing i wrote on the subject when people talk about poststack inversion they are usually talking about recovering. Seismic reservoir characterization and prestack inversion in. The black set of impedances figure 8d represents the ones from seismic inversion, and the blue set of impedances figure 8d represents the ones derived from the estimated rock properties. We perform a prestack seismic impedance inversion on each of the three synthetic surveys.
Normal moveout nmo and stacking of csp gathers is performed to complete the prestack migration process. Whatever the basis for the avo equations figure 11. Seismic inversion is undertaken to complement conventional deconvolution processing. Most of these quantitative studies rely on the seismic reflection amplitude variation with offset avo andor elastic impedance. Prestack basis pursuit seismic inversion for brittleness of shale xingyao yin 0 xiaojing liu 0 zhaoyun zong 0 0 school of geosciences, china university of petroleum huadong, qingdao 266580, shandong, china brittleness of rock plays a significant role in exploration and development of shale gas reservoirs. The geosi method that i will discuss today combines both a gaussian pdf and. Seismic inversion is essentially a very simple procedure. In the case of carbonate sulfur deposits, seismic interpretation is mainly. Prestack inversion has become a common approach in reservoir prediction. Torresverdin, the university of texas at austin, w. Pdf we applied a method of simultaneous prestack seismic inversion spsi in a hydrocarbon field located in the campos basin, brazil.
Graham carter has lived and worked with seismic data in europe, colombia and canada, and for the last 15 years has specialized in reservoir characterization with a focus on seismic. Lithologyfluid inversion based on prestack seismic data. Comparison of post stack seismic inversion methods. Poststack and prestack avo inversion were performed for the hussar data to study the role of using very low frequencies seismic data and initial background.
Pdf seismic inversion methods and some of their constraints. Nonlinear elastic inversion of prestack marine seismic data. Application of simultaneous prestack inversion in reservoir facies. During acquisition of reflection datasets, the seismic signal is sent. In full prestack inversion, both the low and highfrequency components of the pwave acoustic impedance can be extracted from the seismic. Sparkbased intelligent parameter inversion method for. Prestack inversion has many forms, where the major division is between.
Sen2 1department of petroleum and geosystems engineering, one university station, mail stop. Seismic inversion is a technique that has been in use by geophysicists for almost forty years. Strata 1 guide to strata introduction strata is a program which is used to perform poststack or prestack inversion of seismic data. Pdf threeparameter prestack seismic inversion based on l 1. The old and the new in seismic inversion cseg recorder. Abstract this paper presents a method for geostatistical inversion of prestack seismic data to obtain pwave and swave impedances ip and is, respectively. Prestack avo and poststack inversion of the hussar low. Sensitivity, calibration, and application gee shang pan, chi. Mar 28, 2018 seismic exploration is an oil exploration method by utilizing seismic information. Simultaneous inversion of prestack seismic data for rock. Seismic inversion poststacking vs prestacking seg wiki. Pdf nonlinear elastic inversion of prestack marine. Following the prestack signal processing and prestack time migration designed for avo analysis, prestack amplitude inversion is applied to the crp gathers from prestack time migration.
Castaqnat abstract an integrated targetorientedprestack elastic wave form inversion procedure is implemented to estimate lithology, fluid type, and pay thickness of a layered. Seismic migration and inversion describe a class of closely related processes sharing common objectives and underlying physical principles. A method of prestack time migration based on the principles of prestack kirchhoff time migration that can be applied to both 2d and 3d data. It is in general successful in reducing multiple energy yilmaz 2001. Linearized inversion methods often have the disadvantage of strong dependence on the initial model. Prestack inversion with pwave seismic data the procedure for prestack inversion of pwave seismic data followed the workflow presented by hampson et al. Jul 19, 2016 prestack inversion and interpretation to identify potential reservoirs integrated analysis of various seismic attributes, such as poissons ratio, coherence cube and spectral decomposition, to. Stochastic vs deterministic prestack inversion methods cgg.
Pdf threeparameter prestack seismic inversion based on. The first step consists of estimating angledependent reflectivity via a trueamplitude leastsquares kirchhoff prestack migration. Prestack basis pursuit seismic inversion for brittleness of. An integrated targetorientedprestack elastic waveform. Prestack seismic data inversion for shale gas reservoir.
Improving the quality of prestack inversion by prestack data. The seismic signature is replaced by a blocky response corresponding to the seismic impedance layering. Enforcing smoothness and assessing uncertainty in nonlinear. Abstract a new prestack inversion algorithm has been developed to simultaneously estimate acoustic and shear impedances from pwave re. Derivation of avo attributes by prestack amplitude inversion. The traces represent recordings from a collection of different sourcereceiver offsets with a common reflecting midpoint next page, top. Because in simultaneous prestack inversion both low and highfrequency components can be derived from prestack seismic data, this kind of inversion gives more details of the reservoir than poststack inversion. Elastic prestack seismic inversion in stratified media. Deconvolution tries to undo some negative effects of the seismic convolution. Improving the quality of prestack inversion by prestack data conditioning bo zhang 1, deshuang chang2, tengfei lin, and kurt j. Seismic inversion, most of the time used in oil and gas industry, is the process used. Marfurt abstract prestack seismic inversion techniques provide valuable information of rock properties, lithology, and fluid content for reservoir characterization. The ability of seismic reflection technology to image subsurface targets is possible largely through the geometry of sources and receivers.
Simultaneous inversion of prestack seismic data for rock properties using simulated annealing xinquan ma. The target zone is a 3d reservoir, and the inversion problem is solved in a bayesian framework where the complete solution is. At present, the critical issue in the application of seismic inversion is the estimation of elastic parameters in the thin. Figure 312 upper image is the prestack seismic volumes and below the. Firstly, elastic parameters are inverted from seismic data with prestack seismic inversion. Models the kinematic solutions used in seismic migration are relatively straightforward to derive or estimate, and are independent of the type of models used. Depending on the choice of input parameters, inversion can be tracebytrace with.
Direct reservoir property estimation based on prestack. Prestack data are characterized by large data size and rich information. A visual relationship between kirchhoff migration and. Sen, the institute for geophysics at the university of texas at austin. Although the prestack inversion method produces more petrophysical parameters that are sensitive towards fluid and rock property, but the. The elastic parameters themselves can be directly constrained during the seismic inversion and rockphysics relationships can be applied, constraining pairs of elastic parameters to each other. Estimating elastic parameters from prestack seismic data remains a subject of interest for the exploration and development of hydrocarbon reservoirs. Inversion in general means youre trying to get at velocity andor density or their product, impedance, from the recorded seismic data. Pdf simultaneous prestack seismic inversion in a carbonate. Enforcing smoothness and assessing uncertainty in non. Common scatter point csp gathers are created as an intermediate step for each output migrated trace. Invert prestack seismic operator to retrieve a set of elastic property profiles from bandlimited seismic prestack data i. Precision seismic inversion for prestack poststack. An integrated targetorientedprestack elastic waveform inversion.
In prestack time migration, we discussed 2d prestack time migration as the rigorous solution to the problem of conflicting dips with different stacking velocities. Enforcing smoothness and assessing uncertainty in nonlinear onedimensional prestack seismic inversion omar j. 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. Simultaneous inversion of shallow seismic data for imaging. These processes range in complexity from the simple nmostack to the complex, iterative, multidimensional, prestack, nonlin ear inversion used in the elastic seismic case. Marfurt abstract modern 3d seismic surveys are often of such good quality and 3d interpretation packages so userfriendly that seismic interpretation is no longer exclusively carried out by geophysicists. These methods use colored inversion, model based inversion and sparse spike derived impedances as external attributes and seismic and well log data as internal attributes for the geostatistical analysis. Prestack inversion can be done on moveoutcorrected flattened, unmigrated common image point gathers. Seismic inversion methods and some of their constraints.
Prestack basis pursuit seismic inversion for brittleness. In a seismic inversion the original reflectivity data, as typically recorded routinely, is converted from an interface property i. Seismic inversion, channel lithology, genetic algorithm, llanos basin. The algorithm uses a global optimization procedure in the form of simulated. Seismic reservoir characterization of the haynesville shale. A comparison of porosity estimates obtained using post. Common shot, prestack inversion and mode conversion analysis of r d t ic physical model seismic data elect e d by nov 0 7. A comparison of inversion techniques for estimating vpvs. When the reflector geometries that give rise to this problem have a 3d behavior, it is necessary to image the subsurface using 3d prestack time migration.
The first step consists of estimating angledependent reflectivity via a trueamplitude leastsquares. Simultaneous inversion of prestack seismic data dan hampson, brian russell, hampsonrussell software, brad bankhead, veritasdgc. Joint stochastic inversion of petrophysical logs and 3d. Lithologyfluid inversion based on prestac k seismic data marit ulvmoen summary the focus of the study is on lithology. In geophysical inverse problems, data and models are in general non. Well data, structural seismic information and prestack inversion products were combined in an integrated interpretation. I just wanted to explain again a bit, hoping it might help if the op hears it several different ways. Seismic reservoir characterization and prestack inversion. Pitfalls in prestack inversion of merged seismic surveys sumit verma 1, yoryenys del moro2, and kurt j. Upon completion of the course, participants will be able to. Pdf comparing pre and post stack seismic inversion methods a.
Useful reservoir parameter information can be gained through inversion of seismic information to effectively carry out exploration work. Prestack inversion 2016 pcube is a prestack inversion method developed by statoil and the norwegian university of science and technology ntnu. Marfurt abstract modern 3d seismic surveys are often of such good quality and 3d interpretation packages so userfriendly. Different between poststackprestack seismic inversion.
The input data for this process consists of the following elements. Seismic inversion is a technique that has been in use by geophysicists for over forty years. Sen2 1department of petroleum and geosystems engineering, one university station, mail stop c0300, the university of texas at austin, austin. Abstract this paper presents a method for geostatistical inversion of prestack seismic data to obtain pwave and swave impedances ip and is, respectively and access the uncertainty of estimates. The earth medium of interest is elastic with weak lateral variations. Those derived elastic properties were then compared with the ones from the prestack seismic inversion. Pdf the interest in seismic inversion techniques has been growing steadily over the last couple of years. Stacking is a signalenhancement technique that averages many seismic traces.
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