ABSTRACT
It nitrogen injection has been proven as a competitive alternative for volatile oil reservoirs lately found in Piedemonte area of Colombia, taking into account the reservoir fluid nature and the reservoir conditions. A laboratory study was carried out by the authors in the Enhanced Oil Recovery Laboratory of Colombian Petroleum Institute.
Three corefloods were carried out using Berea sandstone and volatile oil samples from the Piedemonte area and nitrogen as displacing agent. One of these corefloods was conducted in a long Coreflooding apparatus, and the other ones, in a short Coreflooding apparatus connected with a slim tube in a order to achieve miscibility conditions. The main variable studied was the flow rate, which represents three different flow regimes. The scaling criteria taken was a dimensionless group, which relates viscous and gravity forces, called gravity number.
Displacement efficiencies determined were around 50%, 65% and 80% for each one the tests. The results of these corefloods were compared to determine the best scheme of nitrogen injection. Results have successfully confirmed the effectiveness of nitrogen as displacing agent for this kind of oils and the better swept efficiency given by the equilibrium between the governing forces.
