Análise geológica e petrofísica de um bloco de travertino como análogo de reservatório de hidrocarbonetos

Abstract

Microbialitic limestones are gaining space in petroleum geology due to the existence of many reservoirs composed of these lithologies in the pre-salt producing fields. Travertine, calcareous tufa and stromatolites figure among the rocks proposed as analogous for the microbialitic rocks. This work conduces the study of geological, petrophysical and geophysical parameters of a travertine block measuring 1,60 x 1,60 x 2,70 m, weighing 21,2 tons and available in the Centro de Estudo do Petroleo (CEPETRO) at the Universidade Estadual de Campinas. The Italian block, named T-block, corresponds to the representative elementary volume of its original formation and allows the study in an intermediate scale between the hand sample and the outcrop scale. Permeability tests and gamma ray spectrometry measurements were conducted and the porosity was calculated by image analysis. Models were generated from the obtained data and then associated with descriptive geology of the block. A reduction in permeability, porosity and concentration of elements potassium (K), uranium (U) and thorium (Th) was recorded, following a gradient towards the top of the T-block accompanying the reduction in the degree of development of the rock fabric.