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Method Research And Appl:Cation Of Pre-stack Seismic Inversion

Posted on:2015-05-16Degree:MasterType:Thesis
Country:ChinaCandidate:H QiFull Text:PDF
GTID:2180330431975679Subject:Earth Exploration and Information Technology
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The technology of seismic has developed rapidly in the past few years. The application of technology is no longer confined to describing the structure;it has entered into the field of reservoir characterization:it has extended from the field of exploration to the field of development.The seismic inversion aimed at predicting the impedance and other parameters about reservoir progeny from seismic data. These estimations are then used for characterizing reservoir;determine the litho logy of rock and finding out the existence and the type of fluid contained in the rock porosity and thus used for the exploration and development of oil and gas resource.The conventional post stack seismic inversion can only obtain the impedance and this has limited its capability of solving geology problems and it cannot meet the demand of refined characterization of reservoir for the developing phase.The technology of pre-stack seismic can obtain much more elastic parameters other than acoustic impedance;it can provide more way to characterizing reservoir and has enhanced the capability of describing complex reservoir and detection of fluid.This paper involves some basal research on rock physics and the basic principles and methods for pre-stack inversion. Such two items as three-parameter AVO inversion and elastic impedance inversion are emphasized during the research.Compared to the past-inversion method,we use seismic inversion of pre-stack data,has the following advantages:pre-stack data is not distortion intact, which contains more information. In the application of reservoir description, the precision is high, bu-tits accuracy is more adapt to the development of lithologic reservoir exploration demand. Pre-stack inversion can make full use of P-wave and S-wave, and has been successfully applied to complex formation thin layer seismic exploration and development. Pre-stack inversion can provide information is sometimes post stack processing cannot provide.As for rock physics.A method for predicting shear-wave velocity, which is based on fluid replacement and improves the accuracy for shear-wave velocity prediction, and two forward modeling procedures, describing the change of seismic response with the change of water saturation in gas sand or oil sand,are presented in this paperAccording to the change of reflected wave amplitude with the incident angle, we analyze the approximate formula based on the Zoeppritz equation, and expounds how to extract the relevant attributes of various methods such as AVO, intercept, slope, the Poisson’s ratio or fluid factor-etc. The establishment of the corresponding relation between reservoir fluid and AVO, and the lithology and hydrocarbon reservoir.Parameter AVO inversion,and come into the following conclusions:it is difficult to obtain three accurate results for three parameters all at one time and is especially difficult for the inversion of density contract,directly solving the three’item AVO equations.Accuracy for estimating density contract can be improved by solving the simultaneous equations which come into being from the result of two different two.Parameter AVO inversion procedures;Survey geometry with large spread length and small receiver interval can improve the inversion as well as AVO inversion by simultaneous PP and PS inversion tests based on the synthetic data from a wedge mode land a saturation-change model reveal that elastic impedance has great capability for complex reservoir characterization and has potential for hydrocarbon detection.In the actual project as an example, we examined the pre-stack seismic data of AVO technology, points out the advantages of pre-stack inversion and application example. This paper from the forward inversion two aspects, on the use of AVO attribute intersection methods map specific expounded respectively.When applied to real data, it comes to good geological effect and thus reveal sits great potential in application.
Keywords/Search Tags:AVO, Forward modeling, Inversion, Fluid replacement, Elastic impedance
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