Seismic imaging algorithms can be divided in two broad categories. Walter lynn this course is designed for those working with reflection seismic data to understand and appreciate the underlying principles and processes leading to final images and associated attributes. He also received segs awards for best paper in geophysics in 1992 imaging salt with seismic turning waves and best paper presented at the annual meeting in 2002 atomic meshing of seismic images. Concepts and applications in 3d seismic imaging geoscienceworld.
Welcome to slim seismic laboratory for imaging and modeling. The goal of seismic imaging is to use these seismograms to reconstruct the earth model, such as the re. Seismic modeling of complex geological structures intechopen. However, because the reader is likely to be familiar with 2d processing methods, i discuss the connections between 3d algorithms and the corresponding 2d algorithms whenever useful. Overviews are often useful and this paper is written for the geophysicist who has not been deeply involved with the design and analysis of 3d seismic survey acquisition for the past 15 years or so, and would like to have an idea of what happened, whats happening now and what is likely to. Free interview details posted anonymously by cgg interview candidates. Pdf seismic imaging methods are currently used to produce images of the earths. He taught segs first course in dipmoveout processing as part of the continuing education program, and was editor of dmo processing, volume 16. In acquisition, long offset 2d and 3d seismic data can contribute to an improvement in the seismic image below top basalt. Geophysical imaging has evolved over the last 30 years due to advances in computing power and speed. The book coherently presents the main components of seismic imaging dataacquisition geometry, migration, and velocity estimation by exposing. However, because the reader is likely to be familiar and comfortable already with 2d processing methods, whenever useful i discuss the connections between 3d algorithms and the corresponding 2d algorithms. Challenges in seismic imaging and reservoir characterization.
Concepts and applications in 3d seismic imaging by biondo biondi. The advent of 3d seismic has transformed the upstream oil industry because it enabled exploration in areas with complex structures lying below complex overburden. The technology allows explorers and drillers with more pinpoint accuracy that goes to should deliver better production and and a slightly longer well life. Biondi is in close contact with the practical applications of seismic imaging by his involvement with 3dgeo development that he cofounded in 1994. Moreover, the seismic data processing and fullazimuth 3d vsp have been enhanced by focusing on improved imaging and characterization of brazilian presalt reservoirs. These include a use of waz data, b use of rtm as the leading tool for psdm, c a move from isotropic model building and depth imaging to anisotropic model building and depth imaging, and d development and use of more sophisticated demultiple techniques, mainly. Seismic imaging is a tool that bounces sound waves off underground rock structures to reveal possible crude oil and natural gasbearing formations. Imaging of complex structures by 3d reflection seismic data. Nmo velocity analysis fourth order nmo the velocities are checked interactively with nmo corrected gathers, stacks and isovelocity plots.
Provides a broad and intuitive understanding of seismicimaging concepts and methods that enables geoscientists to make appropriate decisions during acquisition, processing, imaging, and interpretation. Study on the limitations of traveltime inversion applied. Pictureperfect seismic imaging offshore technology. Mathematics of seismic imaging part i rice university.
How 3d seismic imaging revolutionized the drilling. The anisotropic model, dataset and rtm psdm are called the tempest dataset. Highresolution 2d seismic imaging in the noranda camp and. Seismic energy sources, whether at the earths surface or in shallow boreholes, produce wave types known as. Cgg seismic imaging analyst interview questions glassdoor. The primary objective of this course is to provide a broad and intuitive understanding of seismic imaging concepts and methods that enables geoscientists to make the appropriate decisions during acquisition, processing, imaging, and interpretation projects. The book coherently presents the main components of seismic imaging dataacquisition geometry, migration, and velocity estimationby. Receivers called geophones, analogous to microphones, pick up echoes that come back up through the ground and record the intensity and time of the echo on computers. Regularity is important when analyzing and visualizing the data. Seismic imaging methods are currently used to produce images of the earths subsurface properties at diverse length scales, from highresolution, nearsurface environmental studies for oil and gas.
The project was done in collaboration between devon energy and seismiccity. Data processing methods for 3d seismic imaging of subsurface. The book covers all the important aspects of 3d imaging. Seismic imaging using internal multiples and overturned waves. Recently, however, 3d seismic imaging techniques are used where a fully comprehensive prospect evaluation is desired or where mine planning issues need to be addressed eaton et al. Concepts and applications in 3d seismic imaging seg distinguished instructor series no.
Impedance equals density times the interval velocity. Overview and classification of wavefield seismic imaging. The two seismic profiles were reprocessed to improve the reflectivity in the shallow part of the section and imaging of dipping reflectors. In order to learn about the accuracy of deep water gom model building and depth imaging, we created a 3d vti anisotropic earth model and 3d seismic dataset representing true subsalt gom geology. Methods based on the gradient vector field, obtained from the seismic 3d cross. Velocity model determination on a synthetic complex data set. Paulo johann, reservoir geophysics manager at petrobras, talks to mark brierley about these advances and what they mean for. Enhanced fault imaging from seismic and geological model sebastien lacaze, fabien pauget, benoit luquet and thomas valding, eliis summary can be used to highlight imaging faults is a complex process, which requires a combination of various approaches. Francesco picetti, vincenzo lipari, paolo bestagini, and stefano tubaro. Imaging of complex structures by 3d reflection seismic data biondo biondi stanford exploration project stanford university iprpi workshop on geophysical imaging 1 2d adcig 2 3d adcig. Seismic imaging, particularly 3d imaging, which can unravel the distortions of complex deformational structures and bring small details into focus, enables us to map plateboundary faults down into the seismogenic zone, expose the structure of the colliding plates, and unravel the tectonic history of these settings.
Seismologists use ultrasensitive devices called geophones to record the sound waves as they echo within the earth. Some of the richest energy reserves in the world are just off our us shores waiting to be discovered in a government owned area lying just 3 200 miles out to sea. Seismic imaging methods that are based on ray tracing techniques face with problem in imaging the complex media data. Seismic imaging uses the recorded seismic data to reconstruct an image of the subsurface. Enhanced fault imaging from seismic and geological model. We also understand that when dealing with 3d or 2d depth imaging, manual rms analysis improves the stability of seeding the initial interval velocities of tomographic analysis. In order for a researcher to perform a seismic image, a geophysical tomograph must be utilized. For equation 1 to be valid, negative times must be removed from the downwardcontinued data. Pseudoseismic imaging of magnetotelluric mt data was. Seismic images are crucial to todays exploration and reservoir monitoring. Seismic imaging in and around salt bodies request pdf. Igneous bodies within sedimentary basins are easily identified by two dimensional or 3d seismic reflection imaging due to the large acoustic impedance contrast with the encasing rocks 1, 5, 6. The key principles of seismic imaging are heuristically described in chapter 2, and.
Seismic imaging technology seismic imaging is considered key to reduce risk and cost in exploratory as well as development drilling. It can be easily applied to large data sets as part of a standard processing procedure and can serve as wellconstrained geometrical input for further inversions. Exploit as much as possible the existing regularity in the data geometry. Several new data acquisition, processing and depth imaging technologies were introduced to the industry in the past few years. The basic principle of all seismic methods is the controlled generation of elastic waves by a seismic source in order to obtain an image of the subsurface. Seismic waves are pulses of strain energy that propagate in solids and fluids. The book coherently presents the main components of seismic imaging dataacquisition geometry, migration, and velocity estimation by exposing the links. Study on the limitations of traveltime inversion applied to. Subbasalt imaging is very sensitive to acquisition and processing parameters.
Reverse time migration rtm is an imaging technique that was. Geophysical imaging is a noninvasive imaging technique with a high parametrical and spatiotemporal resolution. Industrys seismic imaging methods share one fundamental assumption. The images is made using a synthetic focusing technique which also needs a smooth velocity model of the earths crust for focusing the image.
Geophysical imaging also known as geophysical tomography is a minimally destructive geophysical technique that investigates the subsurface of a terrestrial planet. Therefore, oil field companies are focusing their efforts on reducing such a negative impact on seismic imaging 2, 3, 4. Seismic imaging directs an intense sound source into the ground to evaluate subsurface conditions and to possibly detect high concentrations of contamination. How 3d seismic imaging revolutionized the drilling industry. The main contribution to the image, as shown in the figure to the right, are reflected waves. Seismic imaging of subsurface geology training course. This book, which accompanies the segeage 2007 distinguished instructor short course, also exposes participants to current trends in imaging research and empowers them to adopt new technologies.
This book, 3d seismic imaging, aimes at helping academic seismology to catchup with industrial practices by introducing the theory of seismic imaging from the 3d perspective. In the 1970ties and 80ties, many tests of highresolution seismic imaging methods for mineral exploration have had only limited success. Earths interior seismic evidence explanation duration. Several processing methodologies were used, including inhouse algorithmsworkflows in addition to service companies solutions. Feb 20, 2014 some of the richest energy reserves in the world are just off our us shores waiting to be discovered in a government owned area lying just 3 200 miles out to sea. The printed volume includes a dvd that includes a complete set of pdf. Seismic imaging is the process of investigating the physical characteristics underneath the surface of the earth. These distributions can be used to understand the subsurface geology and locate deposits of oil and gas. The seismic tool must provide a cost efficient alternative to additional drilling. Everimproving seismic imaging techniques now make it possible to map reservoirs in more detail than before. This book introduces seismic imaging from the 3d perspective, starting from a 3d earth model.
Concepts and applications in 3d seismic imaging distinguished. Concepts and applications in 3d seismic imaging, by biondo l. The customary, conceptual framework of imaging under the. Seismic imaging by 3d partial cds method in complex media.
By studying the echoes, petroleum geologists seek to calculate the depth and. The seismic profiles, not previously shown publicly, provide new information about. Introduction to seismic imaging alison malcolm department of earth, atmospheric and planetary sciences mit august 20, 2010. As seismic imaging of salt is prone to velocity uncertainty and fresnel zone effects, the input of the method is a seismic image that is segmented into three regions. The benefit of using this extension is displayed with a simple box model and the bp model. Ourtechniqueofestimating multiples uses all of the downwardcontinued data, however. Overview and classification of wavefield seismic imaging methods. Seismic imaging customized solutions for every imaging objective. The technique, also known as geophysical imaging, uses the process of revealing sections of the earth with a wave of energy. This is achieved by extending a previously proposed modification of oneway migration so that imaging with overturned waves is possible, in addition to multiples and regular primaries. In fact, canadian geophysicists are internationally recognized as experts in the design, acquisition and processing of 3d seismic programs.