Amplitude Versus Angle (AVA) Simultaneous Inversion of 3-D Partially
Stacked Seismic
Data for Reservoir Delineation and Lithology/Fluid
Characterization in a Deepwater
Contreras, Arturo
J., Carlos Torres-Verdin, William Galloway, The
Pre-stack seismic
data and well logs have been integrated
through AVA simultaneous inversion to delineate deepwater reservoirs
corresponding to the Miocene “M”-series sands in the Marco Polo Field,
modeling
, numerical simulation of
synthetic gathers, and partial angle stacking. Four partial angle stacks were
generated and simultaneously inverted using an AVA-adapted constrained sparse
spike inversion algorithm in order to generate volumes of P-impedance,
S-impedance, and Density. Subsequently, 3D models of porosity and lithology/fluid sensitive modulus attributes (RhoS and RhoF) were computed from
the inversion results.
AVA analysis
indicates that the shale/sand interface represented by the top of the
hydro-carbon-bearing turbidite deposits clearly
generate typical Class III AVA responses; and the layer-dependent Biot-Gassmann analysis shows significant sensitivity of the
modulus attribute RhoF to fluid substitution.
Accordingly, AVA simultaneous inversion, which combines the advantages of AVA
analysis with those of seismic
inversion, have provided quantitative
information about the dimensions, geometry, and lateral continuity of the turbidite reservoir sands which have been interpreted as
stacked depositional lobes. Finally, the spatial distribution of economically
viable areas has been obtained from interpretation of lithology/fluid
sensitive modulus attributes and porosity volumes, thereby significantly
reducing exploration and development risk.