Reações no estado sólido visando mimetizar rochas carbonáticas do pré-sal brasileiro

Abstract

The oil reservoirs in carbonate formations acquired great importance in the Brazilian scenario, especially after the discovery of Pre-Salt, in relation to the characterization of its properties. Depending on the depth of interest, sampling during the drilling of an oil well is a time-consuming and expensive operation, which encourages the search for alternative and continuous samples sources for studies related to carbonate rocks. In this perspective, the preparation in laboratories of porous rock cores that mimic the Pre-Salt rocks is performed as an option that allows easier access to samples, besides assisting the analysis processes and, consequently, contributing to the understanding of these hydrocarbon deposits. The purpose of this Work was to prepare samples and evaluate the influence of initial composition of raw materials, compaction pressure and sintering temperature in the mechanical resistance and structure of the artificial rocks. These artificial specimens were analyzed by visual inspection, X-ray diffraction (XRD) and Raman spectroscopy. The results indicated that the composition of the raw materials interferes in the properties of artificial rocks, but their percentages in the constitution of the aggregate and the addition of cellulose to the nominal composition with heat treatment at 500 °C did not present effects on the mechanical resistance of the rocks. The variation of the compaction pressure did not show any influence of the final characteristics of the specimens. However, the sintering temperature showed significant changes in the physical characteristics of the rocks due to the solid state reactions that the differents temperatures provide. The paraffin bath was demonstrated as a stage to be examined in the future in the production of artificial rocks, because it acts as a physical barrier protecting the products of the sintering of the carbonation and hydrolysis reactions with the atmosphere, avoiding the formation of cracks and ruptures in the structures of artificial rocks.