Grain-grain contacts evaluation in carbonate reservoirs

This work investigate the reasons for the high dispersion seen between elastic velocities and porosity of carbonate rock samples from Brazil. It is based on conventional lab petrophysical measurements, digital x-ray micro tomography image analysis and well logs usage. This gives a multiscale data integration, since micrometers from x-ray images, to metric scale from well logs. A new approach to predict elastic velocities of carbonate rocks from macro and micro porosity, as well as a quality index for grain-grain contacts was proposed. Multivariate regression functions determined for carbonates from Sergipe-Alagoas Basin, were applied to well logs of Santos Basin, which showed that the predominance of micro pores is associated to a higher values of the quality index of grain-grain contacts and to a lower values of elastic velocities. However, it is recommended to generate regression functions for rocks from the own Santos Basin, applying the proposed integrated method of laboratorial, microCT and well log investigation.