Comparison of vertical seismic profiling techniques

Geophysics ◽  
1993 ◽  
Vol 58 (1) ◽  
pp. 134-140 ◽  
Author(s):  
Linda J. Zimmerman ◽  
Sen T. Chen
Keyword(s):  
Three Dimensional ◽  
Seismic Profile ◽  
Oil Field ◽  
Seismic Profiles ◽  
Severe Problem ◽  
Seismic Profiling ◽  
Vertical Seismic Profiling ◽  
Imaging Characteristics ◽  
Profiling Techniques ◽  
Tube Wave

To study the imaging characteristics of various vertical seismic profiling techniques, two vertical seismic profiles (VSP) and a reversed vertical seismic profile (RVSP), where source and receiver positions are interchanged, were collected in the Loudon Oil Field in Illinois. Both VSPs were collected using a line of dynamite charges on the surface as sources. One was collected with geophones and the other with hydrophones as downhole receivers. The RVSP was collected by detonating 25 gram explosive charges in a well and detecting the seismic response with geophones at the surface. Three subsurface images (VSP with geophones, VSP with hydrophones, and RVSP) were produced using VSP-CDP transforms. For comparison, a surface seismic profile was collected along the same line with dynamite sources and vertical geophone receivers. The RVSP and hydrophone VSP stacked sections both produced higher frequency images at shallower depths than did the geophone VSP stacked section. However, the lower frequency geophone VSP stacked section produced an interpretable subsurface image at much greater depths than either the RVSP or the hydrophone VSP sections. The differences are due in part to the more powerful surface sources that were used for the VSPs than the downhole sources used for the RVSP. Furthermore, tube‐wave noise was a more severe problem for both the RVSP and the hydrophone VSP than for the geophone VSP. The results of this experiment demonstrate that if tube‐wave noise could be suppressed, hydrophone VSPs would provide attractive alternatives to geophone VSPs, because it is much easier and cheaper to deploy multilevel hydrophones downhole than geophones. Also, if a high‐powered, nondestructive source is developed, RVSP could be a practical alternative to VSP since one can easily lay out numerous receivers on the surface to record multioffset or three‐dimensional (3-D) VSP data.

An examination of tube wave noise in vertical seismic profiling data

Geophysics ◽  
1981 ◽  
Vol 46 (6) ◽  
pp. 892-903 ◽  
Author(s):  
B. A. Hardage
Keyword(s):  
Body Wave ◽  
Effective Means ◽  
Power Spectra ◽  
Effective Field ◽  
The Body ◽  
Seismic Profiles ◽  
Seismic Profiling ◽  
Vertical Seismic Profiling ◽  
Vsp Data ◽  
Tube Wave

Tube waves act as noise that camouflages upgoing and downgoing body wave events which are the fundamental seismic data measured in vertical seismic profiling (VSP). In two onshore vertical seismic profiles, the principal source of tube waves is shown to be surface ground roll that sweeps across the well head. Secondary tube wave sources revealed in these VSP data are the downhole geophone tool itself and the bottom of the borehole. Body wave signals are also shown to create tube waves when they arrive at significant impedance contrasts in the borehole such as changes in casing diameter. Computer simulated vertical geophone arrays are used to reduce these tube waves, but such arrays attenuate and filter body wave events unless static time shifts are made so that the body wave signal occurs at the same two‐way time at each geophone station. Consequently, actual downhole vertical geophone arrays are not an effective means by which tube waves can be eliminated. Power spectra comparisons of tube wave and compressional body wave events demonstrate that band‐pass filters designed to eliminate tube waves also suppress body wave signals. A simple but effective field technique for reducing tube waves is shown to be proper source offset. Using velocity filters to retrieve upgoing compressional events from VSP data heavily contaminated with tube wave noise yields in one example an agreement with surface measured reflections that is superior to that obtained from synthetic seismograms calculated from log data recorded in the same well.

Application of instantaneous rotations to S‐wave vertical seismic profiling

Geophysics ◽  
1997 ◽  
Vol 62 (5) ◽  
pp. 1365-1368
Author(s):  
M. Boulfoul ◽  
Doyle R. Watts
Keyword(s):  
High Amplitude ◽  
Seismic Profile ◽  
P Wave ◽  
Petroleum Exploration ◽  
S Wave ◽  
Amplitude Variation With Offset ◽  
Seismic Profiling ◽  
Vertical Seismic Profiling ◽  
Seismic Models ◽  
Low Amplitude

The petroleum exploration industry uses S‐wave vertical seismic profiling (VSP) to determine S‐wave velocities from downgoing direct arrivals, and S‐wave reflectivities from upgoing waves. Seismic models for quantitative calibration of amplitude variation with offset (AVO) data require S‐wave velocity profiles (Castagna et al., 1993). Vertical summations (Hardage, 1983) of the upgoing waves produce S‐wave composite traces and enable interpretation of S‐wave seismic profile sections. In the simplest application of amplitude anomalies, the coincidence of high amplitude P‐wave reflectivity and low amplitude S‐wave reflectivity is potentially a direct indicator of the presence of natural gas.

scholarly journals Tube Wave removal from vertical seismic profiling (VSP) surveys

2012 ◽  
Vol 2012 (1) ◽  
pp. 1-4
Author(s):  
Dariush Nadri ◽  
Milovan Urosevic ◽  
Paul Wilkes ◽  
Mehdi Asgharzadeh
Keyword(s):  
Seismic Profiling ◽  
Vertical Seismic Profiling ◽  
Tube Wave

Azimuthal investigation of compressional seismic-wave attenuation in a fractured reservoir

Geophysics ◽  
2019 ◽  
Vol 84 (6) ◽  
pp. B437-B446 ◽  
Author(s):  
Fateh Bouchaala ◽  
Mohammed Y. Ali ◽  
Jun Matsushima ◽  
Youcef Bouzidi ◽  
Eric M. Takam Takougang ◽  
...  
Keyword(s):  
United Arab Emirates ◽  
Seismic Wave ◽  
Wave Attenuation ◽  
Three Dimensional ◽  
Fractured Reservoir ◽  
Flow Mechanism ◽  
Seismic Wave Attenuation ◽  
Seismic Profiling ◽  
Vertical Seismic Profiling ◽  
The Rose

Three-dimensional vertical seismic profiling data acquired from an oilfield located in Abu Dhabi, United Arab Emirates, were used to obtain a high-resolution multioffset azimuthal estimate of compressional seismic wave attenuation. On the basis of the assumption that the fracture strike corresponds to the azimuthal direction [Formula: see text] at which the attenuation is minimized, fracture orientations were obtained in three reservoir units. Two approaches were used to determine [Formula: see text]: first from the variation of the absolute attenuation [Formula: see text] with the azimuth and second from the variation of the relative attenuation [Formula: see text] with the azimuth. The rose diagrams of [Formula: see text] estimated from the [Formula: see text] variation indicated better agreement with those showing the strikes of open and cemented fractures obtained from core interpretation than with either of those showing the two types of fractures separately. However, the rose diagrams of [Formula: see text] estimated from the variation of [Formula: see text] were more similar to those showing the strikes of open fractures obtained from core and Fullbore Formation Microimager data. This observation can be explained by the fact that in the first approach, all types of fractures contribute to the scattering and fluid-related mechanisms of [Formula: see text]. However, in the second approach, [Formula: see text] is obtained from a least-squares fitting of the variation of [Formula: see text] with the azimuth, which is based on the squirt flow mechanism that is caused by the movement of fluid between grain pores and fractures. Therefore, a comparison of the orientations obtained using these two approaches can be an efficient way to separately determine the orientations of open and cemented fractures.

Analysis and removal of multiply scattered tube waves

Geophysics ◽  
2000 ◽  
Vol 65 (3) ◽  
pp. 745-754 ◽  
Author(s):  
Gérard C. Herman ◽  
Paul A. Milligan ◽  
Qicheng Dong ◽  
James W. Rector
Keyword(s):  
Wave Field ◽  
Large Amplitude ◽  
Data Set ◽  
Impedance Function ◽  
Seismic Profiling ◽  
Vertical Seismic Profiling ◽  
Total Data ◽  
Vsp Data ◽  
Tube Wave

Because of irregularities in or near the borehole, vertical seismic profiling (VSP) or crosswell data can be contaminated with scattered tube waves. These can have a large amplitude and can interfere with weaker upcoming reflections, destroying their continuity. This type of organized noise cannot always be removed with filtering methods currently in use. We propose a method based on modeling the scattered tube‐wave field and then subtracting it from the total data set. We assume that the scattering occurs close to the borehole axis and therefore use a 1-D impedance function to characterize borehole irregularities. Estimation of this impedance function is one of the first steps. Our method also accounts for multiply scattered tube waves. We apply the method to an actual VSP data set and conclude that the continuity of reflected, upcoming events improves significantly in a washout zone.

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