This method solves for s impedance, p impedance, and density, which are key for descriminating lithology, porosity, and fluid effects. Summary in this paper, we present a new approach to the simultaneous pre stack inversion of pp and, optionally, ps angle gathers for the estimation of pimpedance, simpedance and density. Pdf seismic inversion methods and some of their constraints. Threeparameter prestack seismic inversion based on l12. It handles a large range of seismic data in dedicated workflows from data conditioning to quantitative property estimation. It leverages the existing simulated annealing inversion, a proven and robust poststack. A narrow meaning of seismic inversion commonly referred to as trace inversion, is acoustic impedance estimation from a broadband timemigrated cmpstacked data. In a seismic inversion the original reflectivity data, as typically recorded routinely, is converted from an interface property i. Modern quantitative interpretation qi extracts additional, high value information from the usually prestack seismic data. Comparing pre and post stack seismic inversion methods a case study from scotian shelf, canada 589 illustra te trim sta tic gather generated after pre conditionin g.
Much of such work and procedures are handled on poststack seismic data. Want to learn more or request a demo about introduction to seismic inversion in paradigm. Virtually all seismic data processing is aimed at imaging the earths subsurface, that is, obtaining a picture of subsurface structure from the seismic waves recorded at the earths surface. Dug insight takes a fresh approach to seismic interpretation software, with powerful features integrated into an easytouse interface. An integrated targetorientedprestack elastic waveform inversion. Interwell seismic inversion and reservoir characterization. Poststack inversion estimates rock acoustic impedance which is not unique in identifying lithology and fluid contents of reservoirs. Different between poststackprestack seismic inversion. Seismic processing and imaging gain deeper insight with the industrys most accurate subsurface imaging tools. From the outset, we contribute specialist reservoir knowledge and skills to the initial project design and modeling, and throughout the data processing and depth imaging phases, we ensure that the. 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. Poststack seismic inversion, and simultaneous prestack inversion for. Seismic inversion may be pre or poststack, deterministic, random or geostatistical.
Simultaneous prestack seismic inversion in a carbonate reservoir. A broad meaning of seismic inversion commonly referred to as elastic inversion, is the grand scheme of estimating elastic parameters directly from observed data. Using field data acquired in a fluvialdeltaic sedimentaryrock sequence, we show that deterministic prestack seismic inversion. Comparing pre and post stack seismic inversion methods. Prestack event interpretation uses a true 4d tracker, seeded from gather picks and horizons. Tech paper divingwave refraction tomography and reflection tomography for velocity model building. Strata performs both poststack and prestack inversions. Pre stack 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. Pitfalls in prestack inversion of merged seismic surveys. Other combinations of elastic parameters such as pimpedance, vpvs ratio and density are equally possible. Simultaneous inversion of prestack seismic data for rock properties using simulated annealing xinquan ma. Prestack seismic faciescontrolled joint inversion of.
Comparing pre and post stack seismic inversion methods a. Existing seismic joint inversion methods for estimating the elastic and petrophysical parameters of a reservoir are primarily based on either the gassmann equation, with which these parameters are inverted from prestack seismic data through stochastic optimization. Our ethos focuses on forging strong working relationships with our clients, to enable a process of feedback and continuous. For prestack data analysis, such as extraction of amplitudeversusoffset avo attributes interceptgradient analysis or simultaneous impedance inversion, the input seismic data must be preconditioned in an amplitudepreserving manner.
The surface of the earth at z 0 acts as a mirror in reflection wave propagation, producing a correction term to the integral in eqn 5. For each input partial stack a wavelet is estimated. Psi is fast to analyse log data to determine whether elastic and petrophysical parameters can distinguish rock properties and hence determine whether pre stack inversion is even worth trying. Common scatter point csp gathers are created as an intermediate step for each output migrated trace. Post stack inversion estimates acoustic impedance using individual seismic traces, while pre stack inversion estimates elastic parameters using a linear model of amplitude versus offset. Seismic inversion is a technique that has been in use by geophysicists for almost forty years. What are the benefits of kingdom pre stack seismic inversion. An approach to reduce exploration risk using spectral decomposition, prestack inversion, and seismic facies classification. The inversions were carried out using the software hrs9 cggveritas.
Kingdom prestack inversion to be released seismic inversion. One main advantage of using prestack seismic inversion for. Seismic inversion uses inverse modeling techniques to address acoustic and elastic inversion, rock physics analysis, and reservoir property modeling. Interwell is a seismic inversion and characterization software for reservoir and exploration geophysicists, available in linux and windows environments. The lowfrequency trend of acoustic impedance is usually derived from well logs or stacking velocities and used as a priori information during the inversion process.
Pdf stochastic inversion of prestack seismic data using fractal. Hampsonrussell software includes a readymade workflow containing the most frequently used gather conditioning processes, but the user has complete control over the workflow steps and parameters and can choose to add additional processes, for example, an offset scaling step. It might be easy to accept this bias, given that the seismic data sets exceed terabytes. The inversion is performed with the cgg veritas hampsonrussell software. We are a highly experienced, independent software company specialising in depth conversion and seismic inversion software. Nevertheless, in practice, applications of inversion methods can be grouped in two categories data modeling and earth modeling. An approach to reduce exploration risk using spectral. Prestack migration an overview sciencedirect topics. The procedure of the data analysis is depicted in the following flow chart.
The petrel prestack seismic interpretation plugin enables prestack seismic visualization, interpretation, and interactive processing to bridge the gap between prestack and poststack interpretation workflows. Pcube is a seismic inversion software that computes lithology and fluid probabilities from seismic avo data, using elastic rock property facies definitions as input. A comparison of inversion techniques for estimating vpvs. Inversion of seismic data to acoustic impedance allows an integrated approach to geological interpretation. Seismic inversion is essentially a very simple procedure. Upon completion of the course, participants will be able to. Petrel quantitative interpretation is a product development collaboration between schlumberger and ikon science. Deconvolution, for example, aims to sharpen reflections, and common midpoint cmp stacking exploits data redundancy to enhance signaltonoise ratio while producing a seismic time section that simulates. Tgs offers inversion as the transformation of both poststack and prestack seismic traces into impedance data the lowfrequency trend of acoustic impedance is usually derived from well logs or stacking velocities and used as a priori information during the inversion process. Our ethos focuses on forging strong working relationships with our clients, to enable a process of feedback and continuous development of our software toolsets. An integrated targetorientedprestack elastic waveform. Using the same pwave angle gathers created for the previous inversion, we also include input from the converted wave data.
Application of crossplot and prestack seismicbased impedance. The relative impedance approach recognizes that while a gli inversion has problems with the lowerthanseismic and higherthan seismic frequencies, the impedance inversion is reliable and unique over the seismic bandwidth and can be filtered back to the seismic bandpass. 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 basis of the method is outlined here, and given in more detail in lumley and beydoun 1991, and lumley 1993. However, one can argue that measuring the efficiency of a programming language should include time to production deployment, not just cpu time. Both post and pre stack inversion require quite a bit of processing to prepare the data, including velocity analysis to flatten common midpoint gathers. Seismic inversion integrates data from various disciplines and domains well data in depth, seismic interpretation and amplitudes usually in time. Well logs are first conditioned and edited to ensure there is a suitable relationship between impedance logs and the desired properties. Prestack depth migration is essential to seismic reflection imaging in areas where steeply dipping structures or extreme lateral velocity variations exist in the subsurface, such as along the flanks of salt domes or in strikeslip fault zones. Using field data acquired in a fluvialdeltaic sedimentaryrock sequence, we show that deterministic prestack seismicinversion. Typically the result is a more complete set of information than any of the individual processes can achieve alone well correlation, geological model building, seismic avo analysis. The elastic and petrophysical parameters of a reservoir can be directly applied to lithology prediction and fluid identification.
The algorithm uses a global optimization procedure in the form of simulated. They are relatively lowlevel and in some cases have their own data formats and involve learning an extensive syntax or metalanguage. Dug insight seismic interpretation software downunder. Castaqnat abstract an integrated targetorientedprestack elastic wave form inversion procedure is implemented to estimate lithology, fluid type, and pay thickness of a layered target zone from. Seismic inversion, in geophysics, is the process of transforming seismic reflection data into a quantitative rockproperty description of a reservoir.
The domain studied in the prestack wave migration is the lower half space, i. Our seismic interpretation software, dug insight is a fullfeatured 2d3d pre stack visualisation and interpretation package. Comparison of an inversion run in the native depth domain with one run in the traditional time domain. Petrel quantitative interpretation schlumberger software. Assumptions for prestack inversion we use commercial software prestack seismic inversion based on fatti et al. Detection and spatial delineation of thinsand sedimentary. Quality control and preconditioning of the input data.
During the iterative inversion process, the acoustic and shear impedance models are randomly perturbed, and the synthetic seismic data are calculatedandcomparedwiththeobservedseismicdata. Seismic processing, inversion, and ant tracking highgrade drilling locations and enable moreeffective completion operations. In addition to the developments in all aspects of conventional processing, this content represents a comprehensive and complete coverage of the modern trends in the seismic industryfrom time to depth, from 3d to 4d, from 4d to 4c, and from isotropy to anisotropy. Breaking news stories, features, profiles of personalities, comment columns, and association information is. Prestack interpretation seismic attributes seismic propagator synthetics. Pat is an integrated passive seismic tomography package for inverting p and swave travel times for 3d velocity and poissons structure and micro earthquake locations. The first step consists of estimating angledependent reflectivity via a trueamplitude leastsquares kirchhoff prestack migration. The additional accuracy of either dmo or prestack migration over that of conventional poststack migration demands special care in the field acquisition of seismic data. Raypath distortions can be so severe in areas of complex velocity variations that conventional poststack processing often. Interwell is a seismic inversion and characterization software for reservoir and. 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. Welltoseismic match, zerophasing of data in zone of interest and extraction of the wavelet. Seismic inversion historically, seismic data was used to generate images of the geological structure subsurface. Abstract a new prestack inversion algorithm has been developed to simultaneously estimate acoustic and shear impedances from pwave re.
Kingdom seismic inversion velocity modelling equipoise software. To increase stability, constraints have been built into the inversionalgorithm,usingthelowfrequencyimpedance and background vsvp models. The seismic data consists of partially stacked common mid point cmp gathers. Simultaneous inversionis a prestack inversion method that uses multiple offset or angle stacks. Interwell seismic inversion and reservoir characterization beicip. Too coarse a spatial sampling, that is, too large a geophone group interval, may preclude high resolution imaging of steep reflectors by any migration method. These attributes were then used to interpret lithology, porosity and fluid saturation in the target interval, and helped minimize risk during the planning and drilling of new wells. Based on our powerful geodepth product suite, our solutions easily handle the full range of seismic imaging challenges around the globe. 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. Oct 28, 2019 prestack interpretation seismic attributes. Tgs offers inversion as the transformation of both poststack and prestack seismic traces into impedance data.
All models, partial stacks, and wavelets are input into a. These are fullfeatured reflection seismology processing packages, with support for modeling, imaging, and inversion. Seismic reservoir characterization reservoir software cgg. Sensitivity, calibration, and application gee shang pan, chi. Prestack inversion has become a common approach in reservoir prediction.
Extract rock properties from seismic data using seismic inversion for prestack or fullstack analysis. Pst inversion software landtech passive seismic tomography. The goal of prestack seismic inversion is to obtain reliable estimates of pwave velocity v p, swave velocity v s, and density. We perform a prestack seismic impedance inversion on each of the three synthetic surveys. In actual application, under the bin grid of 3d data for each block, technologies like field static correction, prestack denoising, and 3d surface consistent processing are used to obtain the prestack gather data qualified for merged processing with accurate. The first step consists of estimating angledependent reflectivity via a trueamplitude leastsquares. Prestack seismic inversion simultaneously inverts amplitude as a. The reprocessed seismic data was put through prestack simultaneous impedance inversion to obtain p and simpedance attributes, and hence vpvs ratio. At present, the critical issue in the application of seismic inversion. Pdf comparing pre and post stack seismic inversion methods a.
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. Prestack inversion with pwave and converted wave seismic data integration of the converted wave data to the inversion follows a similar path as previously defined for the pponly prestack inversion. 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. Simultaneous inversion of pre stack seismic data dan hampson, brian russell, hampsonrussell software, brad bankhead, veritasdgc. Specialists in depth conversion and seismic inversion software for the oil and gas industry. Poststack processing steps for preconditioning seismic data. Simultaneous inversion of prestack seismic data for rock. The correction term represents a new seismic phase from the reflective mirror with an imaginary source located above the ground surface. 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.
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