Characterization of onshore hydrocarbon reservoirs in the Amazonas Basin using well logging data

Abstract

Reservoir characterization is extremely important for understanding and determining the behavior of hydrocarbon reservoirs. The geophysical well logging, widely applied in the oil industry, helps to obtain essential physical properties (acoustic, electrical, mechanical, radioactive and thermal) by deploying measurement devices in the drilled well. This project aims to carry out the geological characterization of hydrocarbon reservoirs in the Amazonas Basin through the analysis of well geophysical logs. Despite the oil-producing potential of the basin, there are few published papers that use geophysical well logging for reservoir characterization. For this study, composite log data publicly provided by ANP were used. Six exploratory wells drilled in AM-T-84 and AM-T-85 exploratory blocks in the Amazonas Basin were selected. By analyzing the geophysical logs of gamma ray, resistivity, density and neutron from these wells, it was possible to identify the hydrocarbon reservoir interval within the Monte Alegre formation and obtain estimates of thickness, shale volume and porosity. The identified reservoir is relatively thin, with an average thickness of 16 m. The obtained shale volume values were relatively high, due to the influence of shale layers present in the Monte Alegre formation. The effect of clay content affected the interpretation process of the well logs; however, it did not significantly impact the reservoir porosity estimation, which ranged between 10.4 and 23.4 %.