Characterization of the reservoirs of Paracuru formation, Curimã Field, Ceára Basin

Abstract

The methods of multivariate data analysis when permitting the simultaneous study of several parameters are important tools for the quantitative characterizafion of reservoirs. Such methods, when applied to the Curimã Field, Ceará Basin - an oil producer in Aptiàn fluvial - deltaic sandstones brôught a better understanding of the lateral and vertical distribution of the permoporous facies, and as a consequence a more precise characterization of its average properties. Five lithofacies were firstly described based on cores. These lithofacies were grouped in two electrofacies equivalent to reservoirs and nonreservoirs. Through discriminant analysis this classification was used for ali wells of the field, and preferential areas for reservoirs were defined. Additionally, three types of flow units were established, corresponding to more homogeneous interyals and referring to permeability intervals, and when they were mapped fumished an areal distribution of the permoporous variations in the production zones. The permeability values estimate were reached through the mu/tivariate linear regressionanalysis, firstly used for the cored wells, and later used for the resto These estimates were also correlated with the perrneability values found when applying the formation tests, as an attempt to obtain higher result precision based only on the log variables.