Experimental study of application of conventional SAGD compared with SAGD using additives (CO2 and enzyme) for the recovery of extra-heavy crude from Pungarayacu field

Abstract

The Pungarayacu field contains the largest extra-heavy oil accumulation, approximately 4.6 billion barrels of OOIP, so this hydrocarbon due to its very high viscosity don´t tend to move easily through the porous medium towards the well. To improve its mobility ratio, decreasing its viscosity, a possible effective thermal method for the hydrocarbon to move towards the well is steam assisted gravity drainage (SAGD). In the present study, a physical model was designed and built to evaluate SAGD, trying to simulate parameters such as: pressure, temperature and reservoir rock characteristics; two types of experiments were carried out: conventional SAGD y SAGD with additives (GreenZyme and CO2). The experiments were carried out at relatively low and high pressures to evaluate the impact of the pressure, the measurements made were: volume of hydrocarbon produced, recovery factor and the steam injection ratio. The measured parameters allowed to evaluate and compare the feasibility of using a conventional SAGD method or a SAGD method with additives for the reservoir. In the physical model, six displacement tests were carried out knowing that conventional SAGD is an efficient thermal process to recover the oil trapped in heavy and extra-heavy oil reservoirs. When applying the conventional SAGD method with the inclusion enzyme (GreenZyme) in the experimentation carried out, the recovered crude was 60%. In the experiments carried out in this study, it is evident that adding CO2 don’t get the desire based on its solubility, due to the expansion of the gas that cools the system. More experiments are required to evaluate the impact of adding CO2 in a SAGD process based on field conditions.