Caracterização de argilas bentonitas de Cubati-PB visando sua aplicação em fluidos de perfuração base água.

Abstract

Bentonite clays have economic importance because they are used in a wide variety of industrial applications. Due to its action as a viscosity maker and also tixotopic, bentonite is used in the production of fluids for oil fields. In this sense, the oil industry is its main consumer in the country. Since the discovery of beds in Boa Vista – PB, the biggest bed in South America, the country has become self-sufficient in this area but due to unorganised exploitation, the beds of good quality are disappearing. Furthermore, bentonite clay beds exist in the county of Cubati which is the reason of this research paper. Thus, the aims of this research paper are the physical and mining characterization and the reologic study of bentonite clays in the county of Cubati – PB to make use of it as water based fluids for oil fields. This poses as an alternative for the beds in the county of Boa Vista – PB. Seven types of samples were studied and they were characterized by fluorescence studies of X ray, gas picnometry, determination of distribution of particles, X ray diffraction differential thermal analysis, gravimetric analysis and scanning electronic microscopy. From the reologic study it was possible to determine the reologic properties and filtration of clay-water suspensions prepared with the studied bentonites. Such samples presented quantities of MgO, CaO and K2O and have as constituents: smectitic clay, kaolinite and quartz. The volumetric fraction of particles indicated a high level of condensation. It could be shown a small capacity of cation exchange according to the used methodology. The ideal CMC level to be used varied according to the clay. Having as a basis reologic specifications of Petrobrás, three kinds of sample present a very high potential to be used in water-based perforation of oil fields.