Enhancing the oil recovery of heterogeneous reservoirs underlaid by tarmat layer
Alfayfi, Abdullah . 2016
ABSTRACT
Oil reservoirs are sometimes underlain by thick tar mat layers at the oil-water contact.Such tarmat sarefound in many major oil reservoirs in the world and, particularly,in the Middle East. Tarmat screate several problems in the extraction process during the recovery stages.This study is aimed at investigating the effectiveness of chemical(solvents)method on enhancing the crude recovery from such reservoirs.
This study was carried outusing different samples of heterogeneous rocks closer in description to those of the real ones in the region. The implications of tarmat layers on oil recovery were examined with different flooding scenarios including water flooding and a combination of water with different solvents. All experimental runs were conducted at 3500 psi over burden pressure,1500psi pore pressure,and 60°C temperature conditions.Results show that the recovery was reduced by 27.34% and 24.9% with tar present in the system for the samples used.The recovery increased by around 6.86%and 7.0% when a combination of water and toluene were used with tar present. Also, the recovery increased by around 2.67% and 2.21% when a combination of water and chloroform were used.
