Seismic characterization of reservoirs with multiple. Pp multi azimuth, ps multi azimuth, ss multi azimuth. The azimuth is usually specified in degrees with respect to. We are used to the convenience of acquiring overlapping shot gathers in straight lines, as we can sort the data into common midpoint gathers, and then exploit the power of stack in processing to attenuate random noise. Acquiring more azimuths for improved offshore seismic. Multiattributes display and rose diagrams for interpretation. Exploration and development geophysics education and research edger.
Full azimuth seismic acquisition with coil shooting 3 figure 3 coil preplot and coverage distribution tpao is the national oil company of turkey and they are the operators of the kozlu block which is located in the southwestern sector of the black sea. In combination with fine seismic data interpretation, structural details and fault features can be verified effectively. Broadband, longoffset, fullazimuth, staggered marine. Horizon attributes measures of the data that occur along a 3d surface through the seismic volume volume attributes measures of the data that occur over an interval of time through the seismic volume attribute meanings. Cn102053262b method for acquiring azimuth velocity of. Seismic characterization of reservoirs with multiple fracture sets using velocity and attenuation anisotropy data.
The overall objective of this course is to introduce entry level andor junior geophysicists and geoscientists to the essential acquisition and technical processing concepts and principles that form the basis for value added seismic applications in exploration, field appraisal, and reservoir management. In this work, we will demonstrate the performance of our inhouse 5d lowrank based interpolation method on a seismic data acquired using coil shooting full azimuth acquisition. Author links open overlay panel aamir ali a morten jakobsen a b. Us7391673b2 method of wide azimuth seismic acquisition. Secondly, offset vector tile ovt processing, which is convenient for azimuthal anisotropy analysis, is a new technique for wide azimuth seismic processing and beneficial for improving the.
Maz, multiazimuth, three or more coincident naz surveys with different survey. The impact of more recent advances in seismic acquisition, including using an increasing number of marine towed streamers, vertical cables, and ocean bottom cables are less well known. Well data are gotten from rock samples and measurements at depth from a wellbore. Despite the azimuthal variation of velocity, for simplicity, an initial 1d velocity model. Multi azimuth maz, wideazimuth waz or fullazimuth faz seismic acquisition overcomes the limitations of the conventional acquisition. High resolution seismic interpretation full azimuth directional angle gathers traditional versus wavefield separation. The value proposition of 3d and 4d marine seismic data. Basic geophysics course for entry level geophysicists other related persons of oil and gas industry by mobility oil and gas ltd. Key seismic survey technologies for deep complex geological. Therefore, inversion of multiazimuth surface seismic data is restricted by the. The dip and azimuth models are seismic attributes used to help with structural interpretation. The discussion of the acquisition and processing of 3d seismic data is intended to promote an understanding of important data quality issues.
Multi azimuth towed streamer 3d seismic in the nile delta, egypt jim keggin bp, mark benson bp, walter rietveld bp, ted manning bp, brian barley bp, peter cook bp. Pwave seismic processing that can identify these variations in the subsurface and take advantage of them will produce sharper images and improved fracture predictions. Linear matrix operations for multicomponent seismic processing. The following books cover important topics in reflection seismology. Their presence can mask or interfere with underlying primary reflections which can often be weaker in amplitude. Optimal stacking for maz prestack seismic data hung and yin 22 nd international geophysical conference and exhibition, 2629 february 2012 brisbane, australia 2 i i it i i i i a t a c c w t 2 where wit is the stacking weight for each azimuth at time t, ci is the maximum crosscorrelation coefficient obtained in a. Multidimensional seismic data decomposition for improved. An ultra high density, full wide azimuth seismic survey for the future jeanjacques postel cggveritas 2nd finding petroleum event on onshore seismic. Wide azimuth or waz is a term describing a seismic data.
Applied seismic anisotropy for fractured reservoir characterization asaf. We will show that we can recover fullazimuthal interpolated data from highly subsampled data, where the subsampling ratio is 4%. Offset vector tile for wideazimuth seismic processing. Lawton department of geology and geophysics university of calgary dr. The azimuth information of seismic data was enhanced by using wide. Sep 19, 2017 a progression in survey effort from one vessel towing sources and streamers sailing a survey area in two or more directions to several vessels sailing a survey area in two or more directions, some of them possibly only towing sources, represents the operational contrasts between multi azimuth maz, wide azimuth waz, and full azimuth faz 3d seismic.
Therefore what we get by modelling a probability density function pdf from the optimized ensemble is not a posterior. The models can be used to subtract noise patterns or enhance seismic events and improve the signaltonoise ratio in poor quality datasets. In the multi azimuth case, the survey is acquired a number of times in different. Azimuthal processing for fracture prediction and image. In 1997, he founded 3dsymsam geophysical advice, focusing on 3d seismic survey design and analysis. Intuitively, a wideazimuth survey that collects long offset data from all directions might seem to be better but this is not always the case. The resulting angle between the source and receivers, is about 20. Dip azimuth semblance and enhancement crestone seismic. Case studies describing successes but also learnings from failures are particularly encouraged. Seismic attributes are the components of the seismic data, which are obtained by measurement, computation, and other methods from the seismic data.
Seismic amplitude variation with offset and azimuth avoaz inversion is well known as a popular and pragmatic tool utilized to estimate fracture parameters. Print course page pdf email course page about the course. Full azimuth seismic modeling in the norwegian sea. Full azimuth, long offset illumination for complex reservoirs john smythe1. The compass direction of a directional survey or of the wellbore as planned or measured by a directional survey. Time imaging by walter rietveld bp has been acquiring multi azimuth maz streamer seismic in the nile delta since 2003. Seismic azimuthal anisotropy and fracture analysis from pp. The stepbystep demo of the full reflection seismic data processing workflow using a complete real seismic data set places itself as a very useful feature of. Abstracta system of aligned vertical fractures produces azimuthal variations in stacking velocity and amplitude variation with offset, characteristics often reported in seismic reflection data. Seismic imaging technology is data driven, and the book contains many examples. According to a preferred aspect of the instant invention, there is provided a system and method for acquiring seismic data in a marine environment, wherein at least two source vessels are used in conjunction with a recording vessel which tows a plurality of hydrophone cables.
Applications of wide azimuth seismic surveying for signal to noise enhancement and multiple suppression in n. Obstacles in the analysis of azimuth information from prestack seismic data. General seismic processing workflow scribd read books. Applications of wideazimuth seismic surveying for signal. Most multidimensional interpolation methods in seismic processing split the data in some kind of singlefold threedimensional arrangement stacks, constant offset single azimuth blocks, crosspreads, etc, and infill what is missing on this volume. Well data required for interpretation are wireline logs gamma ray logs, resistivity logs, porosity log, sonic logs, density logs and neutron logs or equivalent rock property model, check shot data. Reflection seismic geol463 method principles data acquisition processing data visualization interpretation linkage with other geophysical methods reading.
An azimuthalavocompliant 3d land seismic processing flow david gray, darren schmidt, nirupama nagarajappa, charles ursenbach and jon downton cggveritas, calgary, ab, canada dave. A mathfree look at azimuthal surface seismic techniques. Thus, for high volume, fully automatic seismic data processing, no attempt was made to pick and use swave arrival times in the event location process. Seismic inversion impedance inversion by using the lowfrequency fullwaveform inversion result as an a priori model sanyi yuan, shangxu wang, yaneng luo, wanwan wei, and guanchao wang. Fullazimuth seismic data processing w coil acquisition. Multicomponent technology can be applied in both reservoir development and exploration environments to help resolve many seismic and geological challenges.
Seismic interpretation an overview sciencedirect topics. Highfold, multi azimuth and full azimuth seismic, albeit much more expensive than traditional 3d streamer surveys, has been proved to yield the. The invention provides a method for acquiring the azimuth velocity of a seismic psv converted wave and a method for processing the data of the seismic converted wave according to the acquired azimuth velocity. A single set of vertical fractures aligned along a preferred horizontal direction embedded in a horizontally layered medium can be considered as an effective longwavelength orthorhombic medium.
This search prompted acquisition of multi azimuth and wide azimuth datasets and development of processing algorithms using more complete physics of wave propagation. Time imaging by walter rietveld bp has been acquiring multi azimuth maz streamer seismic. In fact, most early 3d seismic surveys were narrow azimuth, although it was probably a matter of necessity as much as intentional design. To follow the first part of the book, the reader is only expected to have an elementary understanding of 2d seismic methods. Sussex rh10 9qn wide azimuth seismic surveys have recently been highly successful in imaging beneath.
A seismic interpretation study should access the following data sets 2d or 3d seismic data cube. Azimuthal seismic amplitude variation with offset and azimuth. Optimal stacking for multiazimuth prestack seismic data. Conventional marine seismic data acquired using a single vessel to tow one or two seismic source arrays in front of a receiver spread. However, once the results from two or more methods are compared the question may arise. Optimal 3d seismic imaging requires that every subsurface point at the target should be properly illuminated during a seismic survey, and should have reflected seismic energy with a uniform distribution of sourcereceiver offsets, azimuths and incidence angles. A case study dealing with azimuthal velocity anisotropy. Seismic attribute analysis can extract information from seismic data that is, otherwise, hidden in the data and have been used to identify prospects, ascertain depositional environments. Resolution of the seismic reflection method multiple reflections. This book is published in under open access creative commons license. Multi dimensional seismic data decomposition for improved diffraction imaging and high. Gareth williams, richard wombell, luke twigger cggveritas, crompton way, manor royal, crawley, w.
These multicomponent and multiazimuthal seismic inversions are nonlinear. Many interpreters are interested in characterizing fractured reservoirs using 3d surface seismic data, and there are a variety of azimuthal techniques to extract this information from the data. Conventional 3d streamer seismic processing generally ignores any azimuth component in the data. Narrowazimuth seismic data schlumberger oilfield glossary. Preferably, the source vessels will be positioned along side of the towed streamer configuration and most preferably. Multiazimuth streamer seismic in the nile delta part 1. An azimuthalavocompliant 3d land seismic processing flow. The anelastic attenuation factor or q is a seismic attribute that can be determined from seismic reflection data for both reservoir characterisation and advanced seismic processing. Principles of 3d seismic interpretation and applications. The impact of acquisition footprint on seismic attribute analysis has been barely addressed. Summary ani it is becoming popular to extract fracture information from wideazimuth pp reflection seismic data. General seismic processing workflow free download as powerpoint presentation. Seismic attributes and their applications in seismic. Basin, the study area has experienced multiperiods of tectonic activities, leading to.
Multicomponent seismic technology is extremely effective in reducing the risks involved in reservoir development, routinely extending the use of seismic data into the reservoir domain. Multiazimuth maz and wideazimuth waz acquisition 2 shooting directions illuminate different parts of the target, and collectively the overall target illumination will be more uniform and complete. Wide azimuth seismic processing for uae carbonate reservoir. Multicomponent, multiazimuth prestack seismic waveform. The method for acquiring the azimuth velocity of the seismic psv converted wave comprises the following steps. The following paper discusses various azimuthal processing techniques used to identify azimuthal velocity anomalies and azimuthal avo anomalies. The models can be used to create additional seismic attributes like 3d volumetric curvature. Seismic processing techniques allow for seismic lines to deviate around natural obstacles, or use preexisting nonstraight tracks and trails. Seismic data acquisition and analysis in the petroleum industry is a multi billion dollar activity. Multi attributes display and rose diagrams for interpretation of seismic fracture lineaments, example from cuu long basin, vietnam ha t. Seismic characterization of naturally fractured reservoirs. Wide azimuth or waz is a term describing a seismic data acquisition technique where separate source vessels are used to record seismic reflections from areas out to the side of the recording spread. The extracted crack density is not influenced by the phase of the seismic data.
Studies for acceptance, a thesis entitled seismic azimuthal anisotropy and fracture analysis from pp reflection data submitted by ye zheng in partial fulfilment of the requirements of the degree of doctor of philosophy. Reflection seismology or seismic reflection is a method of exploration geophysics that uses. Geol463 seismic method the only method giving complete picture of the. Tie a 3d seismic volume to well, by using the well velocity data through seismic synthetic generation, vsp analysis, inversion and modeling process. This text provides a complete introduction to geophysical data processing. Azimuth and offset in design of successful 3d survey, by. The azimuth information derived from prestack seismic data at target layers is very sensitive to many aspects of the analysis process, making reliability a serious issue. Seismic imaging is considered key to reducing risk and cost in exploratory as well as development drilling. Processing of seismic reflection data using matlab pdf. This led to the development of the multiazimuth towed streamer maz which. Full azimuth seismic acquisition with coil shooting. In addition to authoring 3d seismic survey design 2002, 2012, vermeer has written seismic wavefield sampling 1990, both published by seg. Processing of seismic reflection data using matlab pdf processing of seismic reflection data using matlab.
Abstracta system of aligned vertical fractures produces azimuthal variations in stacking velocity and amplitude variation with offset, characteristics often reported in seismic reflection data for hydrocarbon exploration. A poststack attribute that measures the continuity between seismic traces in a specified window along a picked horizon. Purchase geophysics for petroleum engineers, volume 60 1st edition. Heloise lynn specializes in the expression and use of anisotropy in multi dimensional datasets multi azimuth, multi component, and time lapse, 3d azimuthal seismic acquisition design, azimuthal seismic processing, and azimuthal seismic interpretation. Frequency in the seismic data an alternative approach might be to group them into these categories. The book can thus be used for teaching a firstlevel graduate class as well as a short course for professionals. Be alert of the interpreters role during the processing, especially at psdm stage. An overview of oceanbottom and verticalcable seismic acquisition and processing.
Full azimuth imaging through consistent application of ocean bottom seismic mark thompson 1, borge arntsen1, and lasse amundsen statoil asa, arkitekt ebbels vei 10, 7005, trondheim, norway summary in 1997 the worlds first 3d ocean bottom seismic obs surveys was acquired over the statfjord field rogno et al. Detect the defaults or lacks in a processing sequence. Seismic acquisition geometry impacts the seismic image, so in this article we show how advances in imaging deepwater subsalt plays in the deep water gulf of mexico is a result of the way the industry has embraced the wide azimuth. Birdus cggveritas abstact multi and wideazimuth seismic data acquisition and processing can deliver dramatic improvements in the subsurface illumination, imaging and studies of rock properties. Scribd is the worlds largest social reading and publishing site. They are usually unwanted and hence removed from the seismic to allow for optimal processing, imaging and interpretation results. Obstacles in the analysis of azimuth information from. Full azimuth angle domain imaging zvi koren, igor ravve, evgeny ragoza, allon bartana, paradigm geophysical, dan kosloff, tel aviv university and paradigm geophysical summary this work presents a new seismic imaging system for generating and extracting highresolution information about.
May 23, 2010 an increasingly survey azimuths combined in processing. The workshop will emphasize advances in seismic processing, conditioning, and their impact on analysis and inversion workflows which can satisfy the demands of reservoir characterization. The azimuth is usually specified in degrees with respect to the geographic or magnetic north pole. The map of the offset distribution in the 60 m x 60 m processing bins demonstrates the major benefit of this acquisition technique, in that there is regular and consistent fold, offset and azimuth distribution from bin to bin. One early example is the varg field, operated by pertra, and which lies on the norwegian. Applied seismic anisotropy for fractured reservoir. Geophysics for petroleum engineers, volume 60 1st edition. The book starts from the introduction of the basic concepts and methods in 3d seismic imaging. A primary aim of this book is to explain the process of inverse modelling. Dvd includes a document in pdf format that has been specifically formatted. Multiples are echoes or reverberations of primary reflections. It is assumed multi azimuth streamer acquisition for attenuation of diffracted that naz acquisition and processing is unable to meet the multiples, 72nd annual international meeting, seg, expanded data quality objectives in areas affected by geological barri abstracts, 8992. Multiazimuth and wideazimuth lessons for better seismic. Schlumberger has one of the largest multiclient data libraries in the world, with surveys in a wide range of basins.
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