Using Simulation to Address Challenges of Subsalt Imaging in Tertiary Basins with Emphasis on Deepwater Gulf of Mexico (Paper 23566) Michael Fehler SEG Advanced Modeling Project

SEG Advanced Modeling Project (SEAM) Use numerical simulation to Reduce exploration and development risk through improvements to geophysical methods Relevant and challenging datasets for testing Acquisition design New imaging methods Joint inversion methodologies Advance state-of-the-art of numerical simulation

How? Earth Model representative of GOM DW 35km x 40km x 15km Cell size 20m x 20m x 10m Computer generated datasets Outputs look like real field data State-of-the-art simulation codes Over-sampled for acquisition testing

Perspective View of SEAM Model Figure courtesy C. Stork, Landmark Software and Services

Scope of Work Subsalt acoustic earth model and simulation Extend earth model for shear velocity, anisotropic resistivity Non-seismic simulations:  Gravity  Electromagnetic and Magnetotelluric Acoustic anisotropic TTI simulation Elastic simulation

SEAM Model Geological Indicator Volume Basement1 Mother Salt2 Cretaceous3 Oligocene-Paleo4 Lower Miocene5 Middle Miocene6 Upper Miocene7 Pliocene8 Pleistocene9 Water10 Inv. Lower Mio.11 Inv. Olig-Paleog.12 Inv. Cretaceous13 Salt Suture14 Salt15 Hetero Salt

Rooting the Seismic Simulation to the Rock Properties Engages Several Interest Groups Rock Properties Vshale, Porosity, Fluids, Sat, Pressure, Resis, … Elastic Parms Vp, Vs, Dn, Cij, Q (and their reflectivities) Seismic Waves P, S, qP,S, atten/disp; EM response, Gravity AVO reflectivity inversion for elastic parameters Elasticity inversion for rock/reservoir properties Elastic parameter modeling from Rock properties Seismic modeling from Elastic parameters Interest groups on this end: Imagers, Tomographers, Processors Interest group on this end: Reservoir characterization and Monitoring Joe Stefani, Chevron

Model Properties are Derived from Log and Petrophysical Data

Reservoirs in SEAM Phase I Model Catalogue Pleistocene 5 small turbidite fans Pliocene 2 E-W trending braided channel systems Upper Miocene 2 N-S trending braided channels in eastern half Middle Miocene 2 Large turbidite fans that enter from North Lower Miocene 2 Large turbidite fans that enter from North Vertically integrated Reservoir thickness (white indicates thicker reservoir)

Turbidite and Stream Channel Reservoirs Defined Using Geostatistics

Several Geophysical Parameters Defined Using Consistent Approach

Model Testing to Design Acquisition Tim Brice, WesternGeco

Ensure the Quality of Numerical Simulations Through the Use of Benchmark Codes Comparison of Production and Benchmark Simulations

SEAM PHASE I GRAVITY MODEL Gravity at sea level calculated using GM-SYS 3D g xx g yy g xz g xy gzgz g yz g zz

CSEM Simulation Data Shows Sensitivity to Reservoirs on East Side of Salt

TTI Acquisition Plan ~36,000 shots Vertical Seismic Profiles on 4 wells Quality control Classic dataset extraction Acoustic anisotropic model; tilted axis of symmetry ~36,000 shots ~440,000 surface receivers per shot Vertical Seismic Profiles in 4 wells

Proposed Elastic Acquisition Plan ~12,000 shots ~460,000 surface receivers per shot Seafloor 4-component receivers Vertical Seismic Profiles in 4 wells

Simulation Specifications and Status

SEAM Model Used for Studies of Wave Phenomena Finite Difference Simulation Boundary Integral Simulation

Conclusions SEAM Phase I is providing geophysical data of unprecedented scale Model is robust and easily extended for uses beyond current modeling effort Honor geology, rock, and reservoir properties Numerical datasets available for use in studying acquisition, imaging, joint imaging for exploration and reservoir assessment Joint geophysical imaging approaches

Acknowledgments Research Partnership to Secure Energy for America for support (RPSEA Subcontract No ) SEAM participating companies ( Participating company representatives to the SEAM Management Committee SEAM Board of Directors