Application of a 3-D Hybrid Seismic Inversion on Mar’a Inés Oeste Field, Santa Cruz, Argentina

By

 Marcelo Benabentos¹, Subhashis Mallick¹, Tarek Nafie², Mario Sigismondi³, Juan soldo³

(1) WesternGeco, Houston, TX (2) WesternGeco, Cairo, Egypt (3) Perez Companc, Neuquén, Argentina

Application of a 3-D hybrid seismic inversion on Mar’a Inés Oeste field, Santa Cruz, Argentina Marcelo Benabentos, Subhashis Mallick, WesternGeco, Houston, Texas. Tarek Nafie*, WesternGeco, Cairo, Egypt. Mario Sigismondi and Juan Soldo, PECOM de Pérez Companc S.A., Neuquén, Argentina.

Abstract In this paper, we apply hybrid seismic inversion on a three-dimensional (3D) seismic data set from Mar’a Inés Oeste, one of the major oil and gas fields in Argentina. The Mar’a Inés sandstones are Paleocene in age, the traps are mainly structural, and the reservoir is about 50 m thick, containing either oil or gas. These oil/gas-bearing sands usually cause anomalously high amplitude bright-spots on the stacked seismic data. These bright-spots were generally used as hydrocarbon indicators for this area. Drilling through these bright-spots has resulted in pay, as well as some dry wells.

Hybrid seismic inversion, a combination of prestack waveform inversion and poststack inversions of some amplitude-variation-with-offset (AVO) attributes, allowed us to demonstrate that the Poisson's ratio, obtained from this hybrid inversion was effective in fluid discrimination and provided successful drilling locations. We also demonstrate that the Poisson's ratio contrast; obtainable from a standard AVO is not as effective in fluid discrimination as the one from hybrid inversion.