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EAGE Vibroseis Workshop - Vibroseis acquisition and processing half century later, new developments in data quality and productivity
- Conference date: 13 Oct 2008 - 15 Oct 2008
- Location: Prague, Czech Republic
- ISBN: 978-94-6282-067-8
- Published: 13 October 2008
21 - 34 of 34 results
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Use of Seismic Vibrators for Vertical Seismic Profiling: Considerations for the Choice of Sweep
Authors J. B. U. Haldorsen and W. BorlandUsing the VSP deconvolution method described by Haldorsen et al (2004), the bandwidth of
the processed data is determined only by the signal-to-noise ratio at each frequency. With the
source signature determined from measurement in a very quiet wellbore, the bandwidth of the
deconvolved data extends well beyond the bandwidth of the nominal sweep. We see that this
applies also for a walk-away VSP.
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Vibroseis Works in Russia: Current Status and Prospects
Authors A. Zhukov and M. ShneersonVibroseis works is one of the main geophysical mineral exploration techniques and one of the
principle methods of studying the deep structure of the earth interior. In the process of depth
and regional investigations, vibroseis works turned out to be most effective when correlating
into excitation and recording of reflected waves based on the SRM – CDP multifold reflection
seismic survey, which made it possible to record waves from the top of the basement to
Mohorovicic discontinuity. There are quite a few examples of successful regional works in
Russia: the intersections of the Southern Urals and the adjacent areas of the east of the
Russian Plain and Karelia, the traverse through Magadan region to north-east, to the ocean,
etc.
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Source Measurement Effect on HFVSSM Separation
Authors P. Nagarajappa and D. WilkinsonHFVSsm (High Fidelity Vibratory Seismic) acquisition and separation plays an important role
in today’s land acquisition schemes. The method can improve productivity in the field and at
the same time improve signal characteristics in the data. It relies on measured motion to invert
the acquired data. However, separation can be sub-optimal if the measured motion is not
equal to the true source signature input into the ground. In a recent survey with HFVS
acquisition, we were able to obtain a 30 dB separation between adjacent vibrators, which in
our opinion could be improved with greater reliability of the source measurement. In this
abstract, we discuss the results of this survey and show that separation is affected by source
matrix measurement error.
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The drill bit as a source of seismic vibrations: performance and seismic results
Authors F. Poletto, F. Miranda and C. BellezzaThe drill-bit seismic while drilling (SWD) method provides reverse VSP (RVSP) profiles and
has important analogies with the Vibroseis one.
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Comparison of VSP and Sonic-log Data in Nonvertical Wells in a Heterogeneous Structure
More LessIn borehole geophysics, sonic-log measurements and vertical seismic profiling (VSP) are two
techniques which provide information about the seismic velocity in the structure surrounding
a particular well. These techniques use significantly different frequencies of seismic signals.
The results of sonic-log measurements may thus differ from the results of VSP by the velocity
dispersion. To compare the results of the two measurements, the sonic-log velocities are used
to estimate corresponding sonic-log traveltime in the geologic structure, which is then
compared with VSP traveltime.
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An Overview of Efficient Vibroseis Acquisition Methods
By C. BagainiMany methods have been developed in the past 30 years to speed up Vibroseis acquisition. I give an overview of the most promising ones and propose classification of them into three categories: simultaneous shooting, cascaded sweeps, and slip sweep. The main features of these methods are summarized and some criteria for the selection of the most suitable ones are introduced.
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A field test of the point vibrator land acquisition technology
More LessRecording point receivers or point sources instead of the conventional receiver or source arrays enables individual corrections to be applied before Digital Group Forming (DGF) to compensate for:
- Static variations due to different weathered zone conditions or elevations between the different receivers or sources of the same group,
- Amplitude variations due to different coupling conditions,
- Move-out differences at far offsets.
In addition, a finer spatial sampling of the point receiver or source spread along the inline and crossline directions improves the filtering of source generated surface noise.
A field test of the point source and point receiver methods was performed in 2006 by inserting a point source line and a point receiver line within a “conventional†3D survey acquired with source and receiver arrays. The objective was to allow a fair comparison of these two test datasets with reference array datasets acquired with equivalent fold and geometry.
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Development of Super Heavy Vibrator
Authors P. Buttin and G. CaradecPowerpoint presentation
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Optimizing vibroseis productivity in Saudi Aramco
More LessThe first vibroseis 2D data was acquired with a 48-channel crew in 1967. Twenty four years later, a 2D crew was upgraded to 720-channel 3D seismic crew. Initially, productivity was slow with an average rate of 822 sweeps (137 vibrating points (VP)) per day. In the same terrain conditions, our current 4000-channel 3D production seismic crews operating in flip-flop mode can achieve a rate of 3300 VPs per day. To date, Saudi Aramco have acquired approximately 500,000 linear kilometers of 2D and 220,000 square kilometers of 3D seismic data (Figure 1). This presentation reviews the best practices used to reduce the source and receiver cycle times while maintaining data quality.
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