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)

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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.