A Evolução das Técnicas de Aquisição Sísmica Marítima para a Coleta de Dados Multi-Azimutais
1. III Semana de Inverno de Geofísica
IMECC/UNICAMP
A Evolução das Técnicas de Aquisição Sísmica Marítima
para a Coleta de Dados Multi-Azimutais
Apresentador Franck Le Diagon
Empresa WesternGeco
Data 25 de Julho de 2012
2. III Semana de Inverno de Geofísica
IMECC/UNICAMP
Development of Marine Seismic Acquisition Techniques:
“From Narrow to Full Azimuth”
Presenter Franck Le Diagon
Company WesternGeco
Date 25 July 2012
25. Table of contents
❶ Offset-azimuth distribution
❷ Operational implementation
❸ Geophysical benefits
❷❸
❹ Case studies
26. ❷❸Operational implementation ► Narrow Azimuth
Preplot map Azimuth distribution
NAZ geometry
Number of vessels ▲1
Preplots ▲Straight (simple acquisition)
Line change time ►Important
Azimuth/offset distribution ▼Limited azimuth range of +/- 10°
27. ❷❸Operational implementation ► Multi Azimuth
Preplot map Azimuth distribution
MAZ geometry
Number of vessels ▲1
Preplots ▲Straight (simple acquisition)
Line change time ►Important
Azimuth/offset distribution ▼Limited azimuth ranges of +/- 10°
28. ❷❸Operational implementation ► Wide Azimuth
Preplot map Azimuth distribution
WAZ geometry
Number of vessels ▼2, 3, 4, …
Complex operation
Preplots ▲Straight
Line change time ▼Longer and complex
Azimuth/offset distribution ▲Wider range of azimuths
29. ❷❸Operational implementation ► Full Azimuth (coil)
Preplot map Azimuth distribution
Coil geometry
Number of vessels ▲1
Preplots ►Circular
Line change time ▲Minimal, straight line
Azimuth/offset distribution ▲Excellent offset-azimuth distribution
Better contribution of short offsets
30. ❷❸Operational implementation ► Full Azimuth (dual coil)
Preplot map Azimuth distribution
Dual coil geometry
Number of vessels ▼2, 4
Preplots ►Circular
Line change time ▲Minimal, straight line
Azimuth/offset distribution ▲Excellent azimuth distribution and
ultra long offsets
SEG SEAM model
31. Table of contents
❶ Offset-azimuth distribution
❷ Operational implementation
❸ Geophysical benefits
❹
❹ Case studies
32. ❹Case studies ► Coil feasibility test (Gulf of Mexico)
What is the minimum radius?
Coil radii (km):
5.4
6.0
6.5
7.0