Vertical seismic profile (VSP) data are usually acquired with three-component geophones of unknown azimuthal orientation. The geophone orientation must be estimated from the recorded data as a prerequisite to processing such as P- and S-wave separation, calculation of wave-incident directions, and 3D migration. We compare and combine two methods for estimating azimuthal orientation by least-squares fitting over a large number of shots. Combining the two methods can be done in an automated manner, which provides more accurate estimates of the geophone orientations than previous methods. In the polarization-plane method, we calculate the polarization plane of the first P-wave arrival. Then we subtract the source azimuth to determine the geophone orientation, independently for each geophone, with an angular uncertainty of π , and with no accumulated errors. In the relative-angle method, we obtain relative angles between adjacent geophone pairs using trace crosscorrelations, and operate on all coherent signal...
[1]
Phase identification analysis using directionality and rectilinearity functions in three component seismograms
,
2004
.
[2]
D. Steeples,et al.
Automated orientation of three‐component shallow seismic land data to source‐centered cylindrical coordinates
,
2002
.
[3]
R. Stewart,et al.
3-C geophone orientation and wave modes polarization
,
2001
.
[4]
R. Bloor,et al.
Simultaneous Acquisition of 3D Surface Seismic Data and 3C, 3D VSP Data
,
2000
.
[5]
Jianxin Yuan,et al.
Geophone orientation and coupling in three‐component sea‐floor data: a case study
,
1999
.
[6]
N. Hendrick,et al.
Polarisation Analysis: What is it? Why do you need it? How do you do it?
,
1999
.
[7]
Stewart Greenhalgh,et al.
Orientation of a downhole triaxial geophone
,
1995
.
[8]
M. Becquey,et al.
Three-component sonde orientation in a deviated well
,
1990
.