Puesto Hernández is one of the oldest fields currently producing in Argentina. It was discovered in the 1930s, covers an area of 91 square miles (147 km2) and produces approximately 10,000 barrels of oil per day (bpd).
Knight Piésold carried out the hydrogeologic characterization of the aquifer for Petrobras Argentina S.A. in 2011. The aquifer is located under the facilities of the treatment plant for crude oil, salt water treatment plants 1 and 2 and batteries 3 and 6. Knight Piésold also designed a network of phreatic water flow meters in these facilities and the construction of phreatic water flow wells.