SEAM PHASE I GRAVITY

Neda Bundalo

DENSITY MODEL

- Cell size 40x40x20 m

- Density range 1.003 – 3.140 (2.64) g/cm3

SEAM PHASE I GRAVITY MODEL

SEAM Phase I model: density cube

SEAM PHASE I GRAVITY MODEL

CALCULATED GRAVITY

Gravity (vertical component) Gz

and six tensor components (gradients) Txx, Txy, Txz, Tyy, Tyz, Tzz,

- GMSYS 3D (Geosoft) and 3MOD (LCT Fugro),

- free-air and Bouguer anomalies on two calculation levels: 0 m for marine and 150 m for airborne data,

- recommended data storage formats: Geosoft grid and ascii xyzg. Vector (beige) and tensor (red)

components of gravity field;after Murphy, 2004.

SEAM PHASE I GRAVITY MODEL

CALCULATED GRAVITY

- with and without background density

- density of 2.2 g/cm3 used as a background density (mean voxel density)

- density of 2.0 g/cm3 used for Bouguer correction

SEAM Phase I model: vertical density slice

SEAM PHASE I GRAVITY MODEL

Free-air anomalies at sea levelbackground density 2.2 g/cm3

Txx

Tyy

TxzTxy

Tyz

Tzz

Gz

SEAM PHASE I GRAVITY MODEL

Txx

Tyy

TxzTxy

Tyz

Tzz

Gz

Free-air anomalies at 150 m levelbackground density 2.2 g/cm3

SEAM PHASE I GRAVITY MODEL

Txx

Tyy

TxzTxy

Tyz

Tzz

Gz

Bouguer anomalies at sea levelBouguer correction density 2.0 g/cm3

background density 2.2 g/cm3

SEAM PHASE I GRAVITY MODEL

Txx

Tyy

TxzTxy

Tyz

Tzz

Gz

Bouguer anomalies at 150 m levelBouguer correction density 2.0 g/cm3

background density 2.2 g/cm3

SEAM PHASE I GRAVITY MODEL

CONTRIBUTORS

Dr. Neda Bundalo (Marathon Oil), Dr. Richard Day (ConocoPhillips), John Bain (Bain Geophysical Services, Inc.)

THANKS TODr. Xiong Li, Barry Wiggins, Pat Quist (Fugro Gravity and Magnetics Services, Inc.), Dr. Stuart Hall (Department of Geosciences, University of Houston), Dr. Irina Filina (Hess)

NEXT STEP

COMPARISON OF BASE OF SALT INVERSIONSUSING VERTICAL COMPONENT AND GRAVITY GRADIENTS