Tipificação de argilas em sedimentos turbidíticos usando um modelo empírico para estimativa da capacidade de troca catiônica

Clay minerals occur predominantly in clastic sedimentary basins and are the main components of shales. Although the classification of such minerals arouses the interest of interpreters, this is a hard task to accomplish. In this study, we use an empirical model to estimate the cation exchange capacity (CEC), in order to typify the main clays of turbidite sediments in Campos Basin. Natural gamma-ray measurements favored the estimation of shaliness variation in the sediments, since it is the basic parameter for applying the empirical model for CEC. The result of the application of this simple methodology in two wells drilled in Campos Basin reveals the predominance of kaolinite in the selected sedimentary interval, while sheets of illite and chlorite are noticed at the top of the sediments.