Unconventional petroleum resources in Brazil: an overview

摘要

Throughout the past 50 years of exploration in Brazil Petrobras has discovered oil and gas ina variety of reservoir types in diverse geographical and geological settings. At the time of theirdiscoveries, many of these accumulations were at first considered uneconomical due to highcosts of production as well as to the lack of available technology in the market. This workpresents an overview of the various settings in Brazil where these hydrocarbon resourceshave been discovered, illustrates the advances in technology that allowed Petrobras to makeits production economically viable, and exposes the current challenges in exploration andproduction.Brazilian's current production is of around 1.8 MM bpd, 80% of which comes from giant fieldsin deep waters from Campos Basin Campos Basin (over 1000 m of water depth), mostly fromsandstone turbidites with 20o API oil, a typical heavy oil. Petrobras developed specialhorizontal well technology and pioneer anticipated floating production systems to overcomethe challenges of producing heavy oil from friable sands in such water depths. In addition, thecompany has made significant investments in the refinery park to adjust for heavy oilprocessing.Huge volumes of heavy oil also occur in the shallow Eocene Sandstones reservoirs of SantosBasin and even heavier oil (12 oAPI ) from porous Tertiary carbonate reservoirs in shallowwaters of Campos Basin.A strategic approach integrating oil and reservoir characterization,drilling systems, artificial lifting, and flow technologies are being carried out to overcome thechallenge of producing part of the 30 billion barrels of oil in place already found.Challenges faced by Petrobras include also production from low permeability carbonates,tight sands, fractured basalts, and fractured shales as well as enhancement of the existingproduction from Paran' Basin oil shales.