Moisture Damage, Hydrated Lime, Polymer-Modified and Rutting Resistance

Bitumen and heavy oil represent a huge amount of natural resources. The world total estimated oil in place in these forms is approximately 6 trillion barrels. The high viscosity of these crude oils presents a serious challenge for the production of these resources. Because most of the bitumen and heavy oil contain a significant amount of asphaltene, often as high as 22% by weight. VAPEX or vapor extraction process is a relatively new process for the recovery of heavy oil and bitumen. This process involves the injection of vaporized hydrocarbon solvent into reservoir through a horizontal injection well close to the bottom of reservoir. The solvent vapor dissolves into bitumen or heavy oil and reduces its viscosity by dilution and asphaltene precipitation. Therefore the solvent causes an in-situ upgrading of bitumen and heavy oil. Then the upgraded bitumen and heavy oil is produced by gravity drainage process from another horizontal well which is sets at the bottom of formation. The previous works has suggested low production rate as the main disadvantage of this process due to the low diffusion coefficient of solvent into the heavy oil. In this work, the effect of hot solvent injection (warm VAPEX) on the upgrading of bitumen and heavy oil was investigated. The experiments were performed in two cylindrical sand packed models. Two different types of heavy oil with the viscosity of 2173 and 1500 mPa.s at 25 oC were used in this experimental work. The used heavy oils have asphaltene content about 15%. The results showed that the warm solvent injection causes a drastic reduction in heavy oil viscosity so that the viscosity of produced heavy oil reached to 20cP for both used heavy oils. This upgrading effect is due to asphaltene precipitation. Besides, the results confirmed that the bitumen and heavy oil viscosity is very sensitive to temperature. Also, by changing in the solvent temperature from 50°c to 120°c, the heavy oil recovery would increase by 9%.

کلیدواژه ها:

Bitumen ، Heavy Oil ، Upgrading ، Viscosity ، Thermal-VAPEX Process ، Solvent ، Asphaltene Precipitation