Modelagem Física de Rocha em Carbonatos: Análise do Impacto da Geometria de Poros

Carbonate rocks generally assume heterogeneous pore system, characterized by vugs, molds, channels and fractures. Different pore shapes cause different incompressibility, which affect the elastic parameters and seismic sensibility. This paper proposes the use of Kuster-Toksöz model applied in Glorieta-Paddock carbonate reservoir at Vacuum field - New Mexico, aiming to characterize and classify the porous system, allowing the composition of a multiporous system: 1) spherical, 2) interparticle, and 3) cracks. Therefore, the seismic velocities of P and S waves were calculated with the bulk modulus, shear modulus and density conditions, to dry and fluids saturated rock. The results show that the shape pores upper Paddock under the influence of interparticle and cracks, reflected in lower incompressibility and rigidity of the rock, which potentiates the increase in seismic sensibility to the saturation of fluids, different from other formations that were under spheric or intergranular influences, which increases the rigidity of rock, reducing the seismic sensibility. In this sense, a brief comparison between Kuster-Toksöz and Gassmann models was held, discussing the effect of shape pore on the results, suggesting a better characterization of the rock by Kuster- Toksöz results.