Heat loss effect on oil bank formation during steam flood

Abstract

Heavy oil deposits are unconventional resources that are complex and challenging to produce. These unconventional resources usually require thermal recovery techniques to lower the oil viscosity and improve the mobility of it. Steam flood is a popular thermal recovery method. Understanding the mechanism of steam injection and heat utilization improves the efficiency of heavy oil recovery. In this work, the steam flood is applied to a synthetic unconsolidated sandstone core sample to mimic the Lower Fars heavy oil formation located in northern Kuwait. Experimental work was done to conduct the steam flood to this unconsolidated core sample saturated with heavy oil. The steam propagation and oil bank formation were investigated. X-ray computed tomography (CT) scanner was used during the experiment. The experimental data and X-ray CT measurements were analyzed to quantify the changes in the in-situ oil saturation during the steam flood. The growth of the steam zone was quantified and tracked by the CT images. The CT imaging reconstructions showed the formation of an oil bank and its location from the injection inlet side. The experimental observation indicated that the location of the oil bank was stationary and did not advance further at some point during the steam injection due to the heat loss effect. The analysis of the CT images showed that due to the heat loss, the oil bank size was thin. It was also observed that the steam sweep efficiency was high at the injection end. This study provides valuable information on the in-situ heavy oil saturation distribution during the steam flood for the development of heavy oil fields in Kuwait. The work is the first steam flood under CT imaging scanner facility in Kuwait and among the very few done in the world.