In the Name of Allah
The Most BeneficentThe Most Merciful
Vertical Seismic ProfilingVSP
DEPARTMENT OF GEOLOGICAL ENGINEERING UET LAHORE
CONTENTS
INTRODUCTION
FUNDAMENTALS
PARAMETERS
ACQUISITION
INTERPRETATION
APPLICATIONS
INTRODUCTION
It is a measurement where the seismic source is still at the surface but the receivers are lowereddown into a borehole.
FUDAMENTALS
Fundamentals
Fundamentals
PARAMETERS
VSP Parameters
• About 50 to 100 feet between geophones.• Can be adjusted for non-zero offset VSP.• Usually a mechanical source so that it can be
repeated and the data “stacked” (summed).
WHY
Because
• Higher spatial resolution• Give a better image around the borehole• Especially for the salt dome cases • VSP can provide a pre complete image when
surface seismic data fails due to the steepness of the salt boundaries.
• The correlation with the surface seismic to define the actual formation boundaries on the surface seismic
• It can see reflectors below the well-bottom.
Why Vertical Seismic Profiling (VSP)
13
High-resolution imaging example
Representation of a 3D VSP imaging survey.
(Hornby et al., 2006)
ACQUISITION
Types of VSP Surveys
Types of VSP Surveys
3D VSP
INTERPRETATION
VSP Data InterpretationUp going primaries and multiples
T1= 2T1-TGT2= 2T2-TGTM= 4T1-2T2-TG
VSP Data Interpretation
Down going surface and interbedded multiples
TM= 2T1-2T2+TG
APPLICATIONS
VSP Applications
• Velocity estimation. This is usually called a “check-shot survey”.
• Precise correlation of surface seismic data with depth and the well-logs.
• Separation of primary reflections from multiples for guidance in seismic section.
• Calibrate reflectivity coefficients from well log data.• Provide seismic data processing parameters –
velocity, multiple suppression, deconvolution.
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