Evaluation of Volume and Performance of a Free Phase Recovery System in an Oil Spill – Case Study of an Accident in Araucária, Brazil

Abstract

ABSTRACT On July 16, 2000, about 4000 m3 of crude oil were spilled in a pipeline accident at the REPAR Refinery in Brazil, reaching part of the refinery area and the banks of the Barigui and Iguaçu rivers. An Oil Recovery and Cleanup Action Plan was conducted as a cooperative action between PETROBRAS and the Federal and State environmental agencies. One of the areas which suffered the most impact was Ponto Zero, right behind the pipeline failure site, where there was a lot of time for infiltration. Thus, a large amount of oil infiltrated and a free phase was formed for the oil. An estimate of the free phase volume from fluid levels in monitoring wells was conducted using the method of Lenhard and Parker (1990), on two occasions during the recovery action plan, the first in October 2000 right after the oil spill with a value of 43m3, the second in August 2001, after constructing the hydraulic structures to recover the infiltrated crude oil, at a value of 5.5 m3. The recovery system consisted mainly of closed trenches with well-sorted gravel to control the groundwater level and conduct the oil and water collected to a separator system. This recovery system was very efficient (about 87% in one year of operation), at a relatively low implementation and operation cost.