An overview of seismic azimuth for towed streamers. Many technological developments of the past 10 years have been included. Full azimuth seismic acquisition with coil shooting. We are used to the convenience of acquiring overlapping shot gathers in straight lines, as we can sort the data into common.
Cn102053262b method for acquiring azimuth velocity of. Widenarrow azimuth acquisition footprints and their. As a wideazimuth seismic processing method, the offset vector tile ovt technique provides the most effective and precise data domain in geophysics for the basic seismic processing. This explains the requirement of full azimuth sampling. To this end, azimuthal stacks were produced with equivalent offsetfold contributions to better. In the marine environment, fullazimuth surveys using streamers must tow complicated paths, or use multiple vessels or shoot the survey multiple times.
Mention the word geometry and people think about shapes and angles, and maybe the time they outsmarted an opponent on the pool table. Multiattributes display and rose diagrams for interpretation of seismic fracture lineaments, example from cuu long basin, vietnam ha t. We will show that we can recover fullazimuthal interpolated data from highly subsampled data, where the subsampling ratio is 4%. The dip and azimuth models are seismic attributes used to help with structural interpretation. 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. 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. 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. Seismic characterization of naturally fractured reservoirs. Secondly, offset vector tile ovt processing, which is convenient for azimuthal anisotropy analysis, is a new technique for wideazimuth seismic processing and beneficial for improving the. The presentation will conclude with how the application of how fullwave seismic attributes are. Introduction seismic prestack depth imaging is widely applied to compensate for distortions caused by complex overburden.
Coherence is calculated for a range of dips red lines, and in 3. The models can be used to subtract noise patterns or enhance seismic events and improve the signalto. The topic of anastasia pooles electure is wide azimuth acquisition with radial domain interpolation for fluvial morphology interpretation. Wide azimuth seismic processing for uae carbonate reservoir characterization authors jeanluc boelle. 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. Summary ani it is becoming popular to extract fracture information from wideazimuth pp reflection seismic data. Azimuth and offset in design of successful 3d survey, by.
Offset vector tile domain wideazimuth prestack seismic. We present in this work an exhaustive seismic study which was performed on a subset of a wide azimuth ocean bottom cable seismic acquisition shot over a carbonate field from the u. The offset vector tile ovt is a special prestack seismic gather type, and ovt technology is a seismic processing technology suitable for wide azimuth seismic waz exploration. Seismic data processing investigations in geophysics, vol. Azimuth processing another objective of the new processing flow was to provide suitable data for fracture characterization in the shallow section below the crest. An azimuthalavocompliant 3d land seismic processing flow david gray, darren schmidt, nirupama nagarajappa, charles ursenbach and jon downton cggveritas, calgary, ab, canada dave. Advances in geophysical data processing, vol 1, vertical. One early example is the varg field, operated by pertra, and which lies on the norwegian. During this presentation she will demonstrate how an. The models can be used to create additional seismic attributes like 3d volumetric curvature. Buy seismic data processing investigations in geophysics, vol 2 on free shipping on qualified orders.
Seismic imaging is considered key to reducing risk and cost in exploratory as well as development drilling. Us7391673b2 method of wide azimuth seismic acquisition. 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. Lawton department of geology and geophysics university of calgary dr. The course is designed to familiarize the student with the latest developments in marine seismic acquisition including wideazimuth with its many geometry variants, broadband techniques boosting the high and low frequencies, seabed receivers for both pwave and convertedwave recording, simultaneous source acquisition, and methodologies to improve. A schematic 2d representation of the dipazimuth calculation.
The first edition of this book was a slightly modified version of my dissertation defended in february 2001. Full azimuth seismic modeling in the norwegian sea. Geophysicists recognized the need for wide azimuth acquisition long before the advent of recent commercial wideazimuth surveys, the preliminary results of the early wide and rich azimuth towed streamer surveys were used to evaluate the benefits of this new marine acquisition technology. Broadband, longoffset, fullazimuth, staggered marine. To date, approximately 40% of oil and gas reserves in the world exist in deepwater.
Operational implementation of full azimuth, high density. 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. 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. These techniques all imply additional cost, but the improved final image certainly can justify the price tag by reducing drilling and. Preferably, the source vessels will be positioned along side of the towed streamer configuration and most preferably. An azimuthalavocompliant 3d land seismic processing flow. At present, the study on acquisition footprints has become a hot spot. The azimuth is usually specified in degrees with respect to the geographic or magnetic north pole. In 1991, the almaty geophysical expedition was the first in kazakhstan to receive mdsmertz vibroseismic system and began seismic surveys in line with the standards of western oil companies. Feedback from students attending my course on 3d survey design has helped clarify various notsoclear discussions in the book. In fact, most early 3d seismic surveys were narrow azimuth, although it was probably a matter of necessity as much as intentional design. In 1985, the association established the mangyshlak geophysical expedition. In this work, we will demonstrate the performance of our inhouse 5d lowrank based interpolation method on a seismic data acquired using coil shooting fullazimuth acquisition.
Offset vector tile for wideazimuth seismic processing. Narrowazimuth seismic data schlumberger oilfield glossary. The compass direction of a directional survey or of the wellbore as planned or measured by a directional survey. Read, highlight, and take notes, across web, tablet, and phone. Prestack time migration was completed before starting the new appraisal well, late 2006. Because current waz interpretation is not yet mature and because of the lack of key techniques and tools for ovtdomain seismic interpretation, abundant offset and. Maximizing the value of existing seismic data in the. Acquiring more azimuths for improved offshore seismic. Fullazimuth seismic data processing w coil acquisition. 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. Fullazimuth seismic data can be very expensive to acquire. Intuitively, a wideazimuth survey that collects long offset data from all directions might seem to be better but this is not always the case. As oil companies strive for efficiency and seek to acquire higherquality and more costeffective seismic surveys, greater emphasis is being placed on the design process an efficient design is usually a compromisebetween information that is expected to be retrieved and the cost of data acquisition and processing. Processing of seismic reflection data using matlab pdf processing of seismic reflection data using matlab.
The maximum offset and azimuth distribution achievable is a function of the spread length and width. This second edition has been extended considerably. For the first survey acquired using this technique. Processing of seismic reflection data using matlab pdf. Wideazimuth processing for reservoir characterization. Like so many other terms in seismic processing, geometry carries a slightly different meaning in that it describes the relationship between geophysical data e. Heloise lynn specializes in the expression and use of anisotropy in multidimensional datasets multiazimuth, multicomponent, and time lapse, 3d azimuthal seismic acquisition design, azimuthal seismic processing, and azimuthal seismic interpretation.
In the staggered acquisition that has been deployed in the gulf of mexico since june 2012, significant reductions in line change azimuth distribution. The effects on converted wave seismic data of fractures within the rocks will be described in conjunction with a processing flow to accurately extract this information from the data. Podolak, wojciech kobusinski, henryk kowalski geofizyka torun s. Castagna1 1university of houston 2schlumberger and 3delta geophysics received march 2012, revision accepted september 2012. The method for acquiring the azimuth velocity of the seismic psv converted wave comprises the following steps. Using fullwave, full azimuth seismic data to exploit a. Obstacles in the analysis of azimuth information from prestack seismic data.
Dip azimuth semblance and enhancement crestone seismic. Due to the high risk, high investment and high technology required associated with deepwater exploration and development, it is therefore important to investigate and obtain subsurface reservoir information with as much accuracy. Unless otherwise noted, purchase of seg on demand products allows online streaming access for one year from the date of purchase. 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.