To relief the high demand of energy, countries like United States, Venezuela and especially Canada with 232 billion bbl recoverable unconventional reservoirs which contain bitumen, heavy oil and extra heavy oil as remarkable resources of energy. The reducing high quality oil resources and increase of oil price contributed to production from heavy oil reservoirs in recent years.
This paper investigates the heavy crude oil properties and evaluates the steam-assisted gravity drainage(SAGD) which has become the method of choice for oil sand producers and it is therefore critical to optimize this process. Analysis has been done to realize the influence of different parameters on SAGD. The effects of parameters such as horizontal well length, steam quality, viscosity, porosity, permeability in both horizontal and vertical directions, injection well location, injection rate, shale barrier and grid refinement on proficiency of SAGD are analysed. The following findings were obtained:
Higher vertical and horizontal permeability, injection rate and steam quality have positive effect on oil production while Lower porosity, absence of preheating period and higher injection rate have adverse effects on steam-oil ratio(SOR) . Preheating period has impact on SOR at the start of the process. In fact without preheating period the amount of SOR at the start of process is very high. Horizontal shale barrier has more negative effect on oil production than vertical shale barriers. Locating injector close to the horizontal production well has nugatory impact. The shorter the length of horizontal wells the lower the recovery of oil. This paper explains the aforementioned effects in details.
Results of numerical simulations show that SAGD is advantageous for production of bitumen by considering recovery factor and cumulative steam-oil ratio(CSOR).