Effective Extraction of High Viscosity and Low API Gravity Hydrocarbon Resources With Solvent-Steam Processes

Abstract

Extraction of unconventional resources is vital to meet future hydrocarbon demand. However, the effective extraction of these unconventional resources cannot be accomplished by the application of conventional technologies. This study summarizes different combination of different Enhanced Oil Recovery (EOR) methods to recover effectively the low API gravity and high viscosity crudes to find the main factors affecting the EOR performances most. Several steam flooding, steam assisted gravity drainage, and solvent aided-steam processes (SA-SP) (both with asphaltene solvent and non-solvents) were tested on heavy, extra-heavy, and bitumen resources. Carbon dioxide, propane, n-hexane, and toluene were tested as solvents. While carbon dioxide, propane, and n-hexane are asphaltene non-solvents, toluene is asphaltene solvent. The process performances were discussed in terms of cumulative oil recovery and produced oil quality. Produced oil qualities were compared according to their asphaltene, clay, and water contents. Asphaltene content directly correlates to the water and clay contents of the produced oil samples. As the asphaltene content of produced oil increases while the water content increases, the clay content decreases. The worst produced oil quality was obtained by SAGD and toluene-SAGD. The experiments conducted with the asphaltenes insoluble solvents (carbon dioxide, propane, and n-hexane) produced the highest quality oil with low water content and high deasphalted oil content.