Hydrocarbon reservoirs in carbonate rocks represent circa 50 percent of all oil produced worldwide. Those reservoirs are very complex since they are quite heteregeneous. In Brazil, carbonate rocks gained a great importance with the discovery of the pre-salt reservoirs. Understand and characterize these reservoirs, that present low penetration rates, will require major efforts in research and development. A small contribution in this regard is provided in this dissertation, where three travertines (i.e., Roman, Turkish and Itaboraí) were geologically and geomechanically characterized. The experimental program consisted in the chemical, mineralogical, textural and diagenetic characterization, as well as strength and porosity tests. A comprehensive analysis of test results from the experimental program was carried out in order to seek correlations between the indexes/properties/parameters determined. It was found that the unconfined compression strength of materials is directly proportional to its density, its velocity of ultrasonic wave propagation and to Schmidt test hammer index; and inversely proportional to its porosity. It was also found that the velocity of ultrasonic wave propagation of materials is directly proportional to its density and inversely proportional to its porosity.