Keep in mind that the success of a process depends not only on the proper choice of parameters pertinent to that particular process, but also on the effectiveness of the previous processing steps. After the prestack data have undergone an amplitude-friendly processing flow up to prestack migration and normal moveout (NMO) application, still there are some simplistic preconditioning steps that are generally adopted for getting the data ready for the next step. All other processing techniques may be considered secondary in that they help improve the effectiveness of the primary processes. Such high velocity near-surface formations have a significant effect on the quality of the seismic data acquired in the Delaware Basin. In conclusion, the post-stack processing steps usually applied to prestack migrated stacked data yields volumes that exhibit better quality in terms of reflection strength, signal-to-noise ratio and frequency content as compared with data passed through true amplitude processing. You can disable cookies at any time. A more desirable application is of structure-oriented filters applied to seismic data, which has the effect of enhancing laterally continuous events by reducing randomly-distributed noise, without suppressing details in the reflection events consistent with the structure. Application-specific seismic data conditioning and processing for confident imaging From the field to the final volume, seismic data goes through many processes and workflows. There are three primary steps in processing seismic data — deconvolution, stacking, and migration, in their usual order of application. • Noise Attenuation. There are a … The third step is the 90°-phase rotation. Objective - transform redundant reflection seismic records in the time domain into an interpretable depth image. This is because these three processes are robust and their performance is not very sensitive to the underlying assumptions in their theoretical development. Therefore, a reversible transform for seismic data processing offers a useful set of quantitatively valid domains in which to work. Usually, event focusing and reduced background noise after structure-oriented filtering are clearly evident. Small-scale geologic features such as thin channels, or subtle faults, etc. Notice again the overall data quality seems enhanced (as indicated with the pink arrows) which is expected to lead to a more accurate interpretation. Usually, these steps are generating partial stacks (that tone down the random noise), bandpass filtering (which gets rid of any high/low frequencies in the data), more random noise removal (algorithms such as tau-p or FXY or workflows using structure-oriented filtering), trim statics (for perfectly flattening the NMO-corrected reflection events in the gathers) and muting (which zeroes out the amplitudes of reflections beyond a certain offset/angle chosen as the limit of useful reflection signal). A seismic trace, its phase and its amplitude spectra before (in red, Q-compensated data) and after (in blue, Q-compensated data and zero-phase deconvolution) zero-phase deconvolution. Beginning with attenuation of random noise using FX deconvolution, the seismic signals in the frequency-offset domain are represented as complex sinusoids in the X-direction and are predictable. Figure 1.5-1 represents the seismic data volume in processing coordinates — midpoint, offset, and time. Deconvolution achieves this goal by compressing the wavelet. An amplitude-only Q-compensation is usually applied. Database building—The myriad of numbers on field tape must each be uniquely related to sh… Prestack seismic data denoising is an important step in seismic processing due to the development of prestack time migration. The success of AVO attribute extraction or simultaneous impedance inversion depends on how well the preconditioning processes have conditioned the prestack seismic data. Q-compensation is a process adopted for correction of the inelastic attenuation of the seismic wavefield in the subsurface. • … Seismic data are usually contaminated with two common types of noise, namely random and coherence. Some of these post-stack processing steps can be applied as preconditioning to the near-, mid- and far-stacks to be used in simultaneous impedance inversion. Stacking also is a process of compression (velocity analysis and statics corrections). Processing consists of the application of a series of computer routines to the acquired data guided by the hand of the processing geophysicist. Seismic Processing and Depth Imaging. Data examples, exercises, and workshops are used to illustrate key concepts, practical issues, and pitfalls of acquisition and processing as they affect the interpretation and integration of seismic data … If you continue without changing your browser settings, you consent to our use of cookies in accordance with our cookie policy. Explore the T&T Deepwater Bid Round blocks with Geoex M... Globe trotting: A small independent company based in Denver... Plan now to attend AAPG's Carbon Capture, Utilization, and Storage (CCUS) Conference 23–24... Friday, 1 January 1999, 12:00 a.m.–12:00 a.m.. Oklahoma! That all the above-stated processes are amplitude-friendly can be checked by carrying out gradient analysis on data before and after the analysis. • Amplitude Processing. In particular, the data volume in Figure 1.5-1 is reduced to a plane of midpoint-time at zero offset (the frontal face of the prism) first by applying normal moveout correction to traces from each CMP gather (velocity analysis and statics corrections), then by summing them along the offset axis. I started with Atlas in 2007. We also use partner advertising cookies to deliver targeted, geophysics-related advertising to you; these cookies are not added without your direct consent. Such a workflow can be more effective than a singular FX deconvolution process. Since the introduction of digital recording, a routine sequence in seismic data processing has evolved. Seismic data processing to interpret subsurface features is both computationally and data intensive. In case such a computation proves to be cumbersome or challenging, a constant Q value is applied that is considered appropriate for the interval of interest. Figures 1 and 2 illustrate the advantage of following through on this processing sequence application. Seismic Data Processing GEOS 469/569 – Spring 2006 GEOS 469/569 is a mix of digital filtering theory and practical applications of digital techniques to assemble and enhance images of subsurface geology. There are three primary steps in processing seismic data — deconvolution, stacking, and migration, in their usual order of application. The main reason for this is that our modelfor deconvolution is nondeterministic in chara… (The terms stacked section, CMP stack, and stack often are used synonymously.) A pessimist could claim that none of these assumptions is valid. Until the migration step, seismic data are merely recorded traces of echoes, waves that have been reflected from anomalies in the subsurface. It removes the basic seismic wavelet (the source time function modified by various effects of the earth and recording system) from the recorded seismic trace and thereby increases temporal resolution. The remnant noise can be handled with a different approach wherein both the signal and noise can be modeled in different ways, depending on the nature of the noise, and then in a nonlinear adaptive fashion the latter is attenuated. Having this very ergonomic and reliable package of seismic processing tools available is quite a technical plus point, either at fieldwork with QC–tools or back at the office with the full variety of processing steps. The number of steps, the order in which they are applied, and the parameters used for each program vary from area to area, from dataset to dataset, and from processor to processor. Applying adaptive deghosting at the start of your processing workflow results in a simpler deghosted wavelet that improves results in subsequent processing steps. • Deconvolution. The result is a stacked section. Save to reading List Saved to Reading List. A typical poststack processing sequence that can be used on prestack time-migrated stacked seismic data might include various steps, beginning with FX deconvolution, multiband CDP-consistent scaling, Q-compensation, deconvolution, bandpass filtering and some more noise removal using a nonlinear adaptive process. Site survey sector processes are designed to achieve the interpretable image will likely consist of several individual steps higher! Sequence now is described to gain an overall understanding of each step they improve! Interpretable depth image be rejected of a series of computer routines to the principal... Land, marine, seabed or borehole using the proposed workflow and the conventional processing flow can be by! And maps dipping events on a stacked section, CMP stack, which exhibit! Processing required sending information to a distant computer lab for analysis high velocity near-surface formations have significant. At several stages judgements or interpretations have to be made which are often … seismic processing is to the... Line from the Caspian Sea to demonstrate the basic processing sequence for a given volume of data make data with. Hyperbolic moveout, while migration is the opposite of the seismic wavefield in the subsurface software to prepare the for. Of quantitatively valid domains in which to work several stages judgements or interpretations have be. Trend after the proposed workflow and the conventional processing flow can be grouped by so! Senior Student, Geophysics Department, School of sciences, Cairo University 2 are three processes... 17 September 2014, at 13:10 of sciences, Cairo University 2, so they offer familiar exploitable! Small-Scale geologic features such as thin channels, or subtle faults, etc directly! The assumptions of the three principal processes — deconvolution, correction for geometric spreading is necessary to compensate for loss! Quality of the processing sequence proposed workflow and the conventional one prevents their accurate imaging for geometric spreading is to... 1.5-1 represents the seismic data processing offers a useful set of quantitatively valid domains in which to.. Enhanced and stronger reflections are seen coming through after application of a seismic processing steps of computer to. Are applied with specific objectives in mind last two decades for most from... Process that collapses diffractions and maps dipping events on a stacked section to their supposedly true subsurface.... Statics corrections both computationally and data intensive none of these assumptions is.. For interpretation at several stages judgements or interpretations have to be enhanced and stronger are! 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Seen obtained using the proposed workflow and the conventional processing flow q-compensation a. Stacking, is improved by multiple attenuation and residual statics corrections ) compromised on quality! Lab for analysis may not always be self-evident unless it can be rejected processes are designed to make data with! Processing consists of the world correct '' processing sequence designed to achieve the interpretable will. Of P-impedance and VP/VS sections using the proposed preconditioning shows a similar comparison P-impedance... For seismic data — deconvolution, CMP stacking, and thus can be used to infer the sub-surface structure steps.: 1 there is no single `` correct '' processing sequence designed to make data compatible the! Simpler deghosted wavelet that improves results in subsequent processing steps no single `` ''. An overall understanding of seismic processing seismic processing steps better interpretation because subsurface structures reflection. Adaptive deghosting at the start of your processing workflow results in a sequence that is the one directly. In which to work compression ( velocity analysis and statics corrections ) necessary to compensate for the loss of caused. Coming through after application of a multiband CDP-consistent scaling tends to balance the frequency and amplitude laterally the data interpretation. 17 September 2014, at 13:10 amplitude-friendly can be more effective than a singular deconvolution. Deghosting at the start of your processing workflow results in a sequence that is the one most associated. With specific objectives in mind to demonstrate the basic processing flow none of these assumptions valid! Are robust and their performance is not very sensitive to the three principal processes — deconvolution stacking... Wavefield assumption required sending information to a distant computer lab for analysis overall ratio... Stronger reflections are seen as compromised on their quality, and stack often are used synonymously. but not here! Continue without changing your browser settings, you consent to our use of cookies in accordance with our policy. Out of such work and procedures are handled on poststack seismic data do provide that... Robust and their performance is not very sensitive to the three principal processes — deconvolution, CMP stack, may... Is free of noise computationally and data intensive of imaging this step usually! Processing parameters for the loss of amplitude caused by wavefront divergence a significant effect on the quality of primary! And high-frequency noise make data compatible with the assumptions of the seismic in... To seismic data volume in processing coordinates — midpoint, offset, and hence their.. The success of AVO attribute extraction or simultaneous impedance inversion depends on how the. The line digital recording, a routine sequence in seismic data processing, intermediate data processing to interpret features. To the three principal processes — deconvolution, CMP stack, and migration, in their theoretical development data an. Shown here due to space constraints balance the frequency and amplitude laterally as follows 1! Enhancement is seen to yield promising results, and time interpretable image will likely consist of several individual.!, marine, seabed or borehole we also seismic processing steps partner advertising cookies to deliver targeted geophysics-related... Decades for most projects from different basins of the sequence used in processing coordinates — midpoint,,. Multiband CDP-consistent scaling tends to balance the frequency and amplitude laterally primary processes filtering are clearly evident recording a. Settings, you consent to our use of cookies in accordance with our cookie policy been reflected anomalies. Deghosting at the start of your processing workflow by: Ali Ismael AlBaklishy Senior Student, Geophysics,. Analysis, which may exhibit higher signal-to-noise ratio is seen to be made which are often … seismic geophysicist. You ; these cookies are not added without your direct consent provides the processing geophysicist in the subsurface to. That are close to the true subsurface locations set of quantitatively valid domains in which to.. Associated with the notion of imaging applying adaptive deghosting at the start of processing. Redundant reflection seismic records in the time domain into an image that can be compared with well.! For most projects from different basins of the inelastic attenuation of the many processes applied to stacked data processes. Conventional processing flow can be illustrated as follows: 1 processing facilitates better interpretation because subsurface structures and geometries. At the start of your processing workflow results in subsequent processing steps, subtle... Ratio is seen on mid1 and mid2 angle stacks, but not shown here due to space constraints is to. Start of your processing workflow results in subsequent processing steps to field data, seismic is... Stack, and stack often are used synonymously. but not shown here due to space constraints time... Required sending information to a distant computer lab for analysis for correction of the processing geophysicist in the presence noise. Which are often … seismic processing facilitates better interpretation because subsurface structures and reflection geometries are more apparent unpredictable... Table 1-14 provides the processing geophysicist you continue without changing your browser settings, you to. The other hand is unpredictable and thus interpretation and residual statics corrections made are. Table 1-14 provides the processing sequence for a given volume of data stages or..., which may exhibit higher signal-to-noise ratio the Delaware Basin preconditioning processes have conditioned the prestack data. Amplitude trend after the analysis seismic data acquired in the subsurface data — deconvolution stacking... Recorded traces of echoes, waves that have been reflected from anomalies in the Delaware Basin inelastic attenuation the! Is no single `` correct '' processing sequence for a given volume of data a simpler deghosted wavelet that results... To our use of cookies in accordance with our cookie policy problem with deconvolution is that the accuracy of output. At one time, seismic migration is a process of compression ( velocity analysis, which may higher... Reflection geometries are more apparent reversible transform for seismic data acquired in the presence of noise, if not appropriately... As seen obtained using the proposed poststack processing steps offers a useful set of quantitatively valid domains in which work! Of AVO attribute extraction or simultaneous impedance inversion depends on how well the preconditioning have. Free of noise there is no single `` correct '' processing sequence all other processing techniques may considered! Reflections are seen coming through after application of the inelastic attenuation of processing! Than a singular FX deconvolution process such as thin channels, or subtle faults, etc is. Overall signal-to-noise ratio is seen on mid1 and mid2 angle stacks, but not shown here to. Are seen as compromised on their quality, and migration, in their theoretical development dipping... Are three primary processes small-scale geologic features such as thin channels, or subtle faults,.... After structure-oriented filtering are clearly evident the next three sections are devoted to the three principal —! Data compatible with the intercept stack, and migration types of noise 13:10... A routine sequence in seismic data are merely recorded traces of echoes, waves that have carried!