Feb 15, 2017 in this video you will learn the different methods for depth conversion. In an area with more than 150 wells within the 3d seismic area, approximately 2 wellskm 2, a statistical depth conversion using kriging and simulation techniques becomes the. Converts seismic and attributes data between time and depth option to scales in same domain can use maps, fm. Seismic data analysis techniques in hydrocarbon exploration. Timetodepth conversion and seismic velocity estimation using time. In this video you will learn the different methods for depth conversion. The depth conversion can now be carried out as part of the data processing, but this depth imaging is only done in special circumstances. The book is written for the interpretation geophysicist working in exploration and development, for the seismic processor seeking a wider perspective on the quality. The conversion of twoway seismic times into a depth picture has been done using six different methods for a study area in the gulf of mexico. As a graduate student, this book has become quite the resource for me. Gmdk geomodeling knowledge principles of seismic velocities. Each of these options requires converting the time migration velocity to a velocity model in depth. A simple guide to the parameters involved in seismic depth conversion a. Pdf seismic velocity estimation and time to depth conversion of.
Differentiate the various types of seismic attributes available and select appropriate attributes for a given project. Simply defined, seismic interpretation is the science and art of inferring the. Unless explicitly stated otherwise, average velocity in interpretation usage always refers to the interval velocity between the seismic datum and a time or depth value or surface. The purpose of the log calibration is usually to create. The book focuses mainly on land and offshore geophysical data acquired at. The time coordinate, along with time migration velocities, is determined. Seismic interpretation an overview sciencedirect topics. Time migration produces images in the time coordinate as opposed to the usual depth coordinate. Real 2d seismic section interpretation single lines emphasizing funny.
Time is split equally between teaching and exercises which are designed to illuminate concepts and. Depth conversion interpretation of threedimensional. The course incidentally provides attendees with a geophysics refresher, mapping and. The book is written for the interpretation geophysicist working in exploration and development, for the seismic processor seeking a wider perspective on the quality of output and on the provision of the data to help the frontline geoscientist, for the geologist using geophysical methods as a tool at various levels of detail in the. A simple linear regression model has to be constructed to translate the seismic data picked in the time domain external drift to a smooth trend model in the depth domain. Summary we address the problem of time to depth conversion of time. Depth conversion and seismic lithology inversion of a.
Seismic velocity estimation and time to depth conversion of. Thickness can be determined by seismic stratigraphic interpretation and conversion from time data to depth. The seismic record contains two basic elements for the interpreter to study. Determine factors affecting seismic resolution at the reservoir scale.
Integrated geophysical models principles of seismic. Seismic interpretation better tools, better understanding, in less time. Correlation of seismic attributes and geomechanical. Standard inputs for depth conversion, such as time interpretation, well, and seismic velocities, can produce a wide range of depth structures. Seismic data is acquired in time the time taken for the sound to travel from the source to reflectors and to return to receivers. Principles of seismic velocities and timetodepth conversion alchalabi is a wellknown expert in velocities and time todepth conversions. The actual depth to this surface is a function of the thickness and velocity of overlying rock layers.
Seismic velocity estimation and timetodepth conversion of. A good seismic image is not enough for an exploration or field development interpretation. Publication date 2014 isbn 9781523101412 electronic bk. Shale reservoir characterization is also the focus of 3d seismic interpretation. Alchalabi and a great selection of similar new, used and collectible books available now at great prices. The emerson seismic interpretation suite is an integrated, modern interpretation and visualization system designed to carry out all seismic interpretation tasks, including structural, stratigraphic, and volume interpretation.
The seismic datum is normally above the surface or grid of interest and the td chart has a zerozero entry for time and depth. Reflections arising at interfaces can thus be looked upon as the sum of energy scattered by interface points. Travel time gaussian random field prediction variance vertical well interval velocity. Participants should be familiar with the seismic method and have several years of interpretation experience. Seismic pwave velocity may be measured directly by recording a conventional seismic energy source such as a dynamite charge, a vibrator, or an air gun with a. Also, you can visit our facebook page and group at. To convert from time s to depth ft you must know the velocity of the material. Bayesian kriging for seismic depth conversion of a multilayer reservoir. Seismic interpretation and depth conversion of the. Time to depth conversion and uncertainty characterization for. Seismic interpretation errors are modeled as gaussian random fields. Scopri principles of seismic velocities and timetodepth conversion di alchalabi, m spedizione gratuita per i clienti prime e per ordini a partire da 29 spediti da amazon. Approximating a seismic horizon timedepth conversion using a twovelocity layer approach in seisworks frequently in industry you will want to display a horizon map in depth ft instead of the landmark seisworks default, which is twoway time twt.
Depth conversion concerns the seismic interpreter because seismic measurements are made in time, but the wells based on a seismic interpretation are drilled in depth. A velocity model is required in the form of a voxet. Seismic velocity maps for lithology determination or depth conversion. Categorize the various time to depth conversion methodologies. This book offers a presentation of the practical aspects of reflection seismic interpretation, written by a working explorationist for explorationists. Timetodepth conversion and seismic velocity estimation using timemigration velocitya apublished in geophysics, 73, no.
Wail abdulhakim mousa bridging the gap between modern image processing practices by the scientific community at large and the world of geology and reflection seismology this book covers the basics of seismic exploration. W7 well logs and synthetic seismograms, seismic well calibration 10. Timetodepth conversion and seismic velocity estimation using timemigration velocitya. The objective was to build an efficient algorithm 1 to estimate seismic velocity from timemigration velocity, and 2 to convert timemigrated images to depth. With these technologies, accurate seismic timetodepth conversion or redepthing can be achieved efficiently by seismic interpreters. How to convert depht in doubletime depthtwt, to depths. Timedomain seismic processing has been a popular and e ective tool in areas with mild lateral velocity variations yilmaz, 2001. Depth conversion integrates several sources of information about the subsurface velocity to derive a threedimensional velocity model. Depth conversion domain conversion of seismic time interpretations and data. Introduction gocad offers conversion of horizons and seismic in the time domain to the depth domain and vice versa. The residuals are the difference between the depth predicted by the velocity model using the seismic time at the well marker and the actual depth observed in the well.
Original content in datapages find the book in the aapg store. After careful picking in the time domain, the depth conversion of the bounding surfaces is optimized, then the intra reservoir horizons are scaled between the boundaries. Using an elementary theory of migration one can consider a reflecting horizon as a continuum of scattering centres for seismic waves. Hence, we use the dix velocity instead of timemigration velocity as a more convenient input. Time domain seismic processing has been a popular and e ective tool in areas with mild lateral velocity variations yilmaz, 2001. Next to seismic mapping of the dinantian target level, this study focuses on analysing the most appropriate seismic velocity information for timedepth conversion. In the oil and gas business, seismic time to depth conversion problems are best solved, in many cases, by looking for velocity versus depth relationships on a spreadsheet program with graphics. Then, reflection times are picked by combining seed detection and linebased interpretation strategies interpretation of 3d seismic data. Oz yilmaz has expanded his original volume on processing to include inversion and interpretation of seismic data. Timetodepth conversion and seismic velocity estimation. Compare seismic time to depth conversion techniques and recognize the advantages and disadvantages of different methods. A simple guide to seismic depth conversion i geo expro. Mathematics of multidimensional seismic imaging, migration, and inversion. In the case of a laterally homogeneous medium, the conversion from time to depth is provided by the classic dix method dix, 1955.
Bayesian kriging for seismic depth conversion of a multilayer. Seismic reflection data records the twoway travel time twt to a reflection. The combination of the interval velocity maps from step c with the depth horizons from step d constitutes the initial model derived from time to depth conversion. Prerequisites knowledgeexperienceeducation required. Principles of seismic velocities and timetodepth conversion 9789073834873 by m. In addition to the developments in all aspects of conventional processing, this twovolume set 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. Here we will go through a time to depth conversion of a 2d seismic survey in the sichuan basin using a velocity model provided in depth. Geo expro a simple guide to seismic depth conversion ii.
Approximating a seismic horizon time depth conversion using a twovelocity layer approach in seisworks frequently in industry you will want to display a horizon map in depth ft instead of the landmark seisworks default, which is twoway time twt. Principles of seismic velocities and time to depth conversion 9789073834873 by m. Figure 3 illustration showing effect of lateral differences in velocity on conversion of time and depth. Focusing on the everyday problems facing the working interpreter, this book has a geological emphasis and is aimed especially to those new to interpretation. Compare seismic timetodepth conversion techniques and recognize the advantages and disadvantages of different methods. Good well ties and reliable depth conversion are also required. A time slice view of the data is an improvement over vertical sections for the interpretation of depositional systems because it provides the opportunity to see a portion of depositional systems in map view.
Seismic data interpretation using digital image processing. Here we will go through a time to depth conversion of a 2d seismic survey in the sichuan basin using a. Approximating a seismic horizon timedepth conversion using a. Principles of seismic velocities and timetodepth conversion eage. Depth conversion is an important step of the seismic reflection method, which converts the acoustic wave travel time to actual depth, based on the acoustic velocity of subsurface medium sediments, rocks, water. The rate of penetration rop measures drilling speed, which is indicative of the overall time and in general, the cost of the drilling operation pro. The objective was to build an efficient algorithm 1 to estimate seismic velocity from time migration velocity, and 2 to convert time migrated images to depth. Time to depth conversion and seismic velocity estimation using time migration velocitya apublished in geophysics, 73, no.
Thickness, fracture permeability, brittleness, organic richness, pore pressure, and more can be determined from seismic data chopra et al. Twowaytimetodepth conversion strategy for seismic intepretations, involves. How to convert depht in doubletime depthtwt, to depths in. Seismic data mapping with twodimensional data aapg wiki. Seismic data analysis techniques in hydrocarbon exploration explains the fundamental concepts and skills used to acquire seismic data in the oil industry and the stepbystep techniques necessary to extract the sections that trap hydrocarbons as well as seismic data interpretation skills. A comparison of depth conversion methods in the gulf of. A final comprehensive depth conversion exercise consolidates understanding of the workflow. Approximating a seismic horizon timedepth conversion. Principles of seismic velocities and timetodepth conversion. This book begins with an introduction that is more philosophical than technical, followed by five chapters on fundamentals of reflection seismic titled seismic response, seismic attributes, velocity, migration, and resolution. The authors have found that geologists and geophysicists tend to approach the depth conversion process quite differently. The time slice is the first step toward 3d interpretation of a 3d seismic volume.
Before estimation of the wavelets, the well logs must be calibrated to align with the seismic time data. A timeslice view of the data is an improvement over vertical sections for the interpretation of depositional systems because it provides the opportunity to see a portion of depositional systems in map view. This book embodies the knowledge and expertise he has in the specific area of timetodepth conversions. Jul 19, 2016 with these technologies, accurate seismic time to depth conversion or redepthing can be achieved efficiently by seismic interpreters.
N172 depth conversion methods and pitfalls rps training. A small mean residual difference indicating an unbiased depth conversion and a low standard deviation meaning the method explains the depth quite well are indications of a. A robust approach to timetodepth conversion and interval. Time to depth conversion and uncertainty characterization. Geo expro a simple guide to seismic depth conversion i.
A petroleum geologists guide to seismic reflection. Depth conversion and depth imaging interpretation of three. Part of the quantitative geology and geostatistics book series qgag, volume 5. The combination of the interval velocity maps from step c with the depth horizons from step d constitutes the initial model derived from timetodepth conversion. The time coordinate, along with timemigration velocities, is determined. The first is the time of arrival of any reflection or refraction from a geological surface. The interpreter identifies the time horizons that are associated with depositional sequence boundaries and geologically and lithologically significant layer boundaries within some of the depositional units. A well depth and a seismic horizon time to the same event can be used to define a socalled pseudovelocity and these are often used in depth conversion. From the simplest constant function approach to the layer cake method, and finally to an average velocity technique based upon seismic velocities, each has. The purpose of depth conversion is to filter out erroneous input data whilst understanding the impact of remaining data.
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