Primary production mechanisms do not recover an appreciable fraction of the hydrocarbon initially in place (HIIP). Practical knowledge has shown that, at the point when the natural energy in a heavy oil reservoir is n...Primary production mechanisms do not recover an appreciable fraction of the hydrocarbon initially in place (HIIP). Practical knowledge has shown that, at the point when the natural energy in a heavy oil reservoir is nearly or altogether depleted, the recovery factor does not exceed about 20%. Some heavy oil reservoirs do not produce at all by natural drive mechanisms. This often necessitates adopting a production improvement strategy to augment recovery. Prior to implementing an improved oil recovery method (either secondary or tertiary) in the field, it is very important to investigate its potential for success. Reservoir simulation is a part of a continuous learning process used to gain insight into the feasibility and applicability of improved oil recovery methods. In this project, GEM compositional reservoir simulator has been used to study the efficiencies of different improved oil recovery strategies, ranging from waterflooding to solvent injection. The drainage volume investigated is a hypothetical box-shaped heavy oil reservoir composed of three distinct permeable layers.展开更多
With the depletion of natural driving forces responsible for pushing the oil from reservoirs & declination of oil recovery after secondary stage, the emphasis is now on EOR techniques. The low saline flooding is a...With the depletion of natural driving forces responsible for pushing the oil from reservoirs & declination of oil recovery after secondary stage, the emphasis is now on EOR techniques. The low saline flooding is a type of EOR which gains the attention of researchers due to its easiness to use implications, less cost & environment-friendly nature. Though the low salinity effect has been seen in various labscale core flooding experiments as well as field pilot projects, the mechanism which actually leads to this enhancement in recovery is still the area of research among researchers which is wide open and needs to gain consensus. Seeing the wide mechanisms taking place under different scenarios, it is certain that more than one mechanism is actually supplementing each other in reducing the residual oil saturation while LSW flooding. This study has been undertaken investigations on the low saline flooding in unconsolidated Ottawa sandpack cores with two different, Weyburn & Pelican crude oil, to find out the optimum salinity, LSW Slug Size & underlying mechanisms during LSW flooding. Several core flooding experiments were performed under secondary as well as tertiary recovery stage by unsteady state method. With the reduction of brine salinity from 5000 PPM to 1500 PPM, the oil recovery increased in secondary stage & decreased further upon reduction in salinity to 500 PPM gaining the peak at 1500 PPM. Small enhancement in tertiary recovery of 2.24% observed upon switching to 1500 NaCl PPM brine after injection of formation brine in secondary stage for Weyburn Oil, though large tertiary recoveries of the order of 9.95% for effective oil viscosity of 4 cP and 7.32% for 29.7 cP were observed for n-dodecane diluted Pelican Oil. LSW slug size of 25% pore volume was found to be effective in producing Weyburn Oil in secondary stage.展开更多
文摘Primary production mechanisms do not recover an appreciable fraction of the hydrocarbon initially in place (HIIP). Practical knowledge has shown that, at the point when the natural energy in a heavy oil reservoir is nearly or altogether depleted, the recovery factor does not exceed about 20%. Some heavy oil reservoirs do not produce at all by natural drive mechanisms. This often necessitates adopting a production improvement strategy to augment recovery. Prior to implementing an improved oil recovery method (either secondary or tertiary) in the field, it is very important to investigate its potential for success. Reservoir simulation is a part of a continuous learning process used to gain insight into the feasibility and applicability of improved oil recovery methods. In this project, GEM compositional reservoir simulator has been used to study the efficiencies of different improved oil recovery strategies, ranging from waterflooding to solvent injection. The drainage volume investigated is a hypothetical box-shaped heavy oil reservoir composed of three distinct permeable layers.
文摘With the depletion of natural driving forces responsible for pushing the oil from reservoirs & declination of oil recovery after secondary stage, the emphasis is now on EOR techniques. The low saline flooding is a type of EOR which gains the attention of researchers due to its easiness to use implications, less cost & environment-friendly nature. Though the low salinity effect has been seen in various labscale core flooding experiments as well as field pilot projects, the mechanism which actually leads to this enhancement in recovery is still the area of research among researchers which is wide open and needs to gain consensus. Seeing the wide mechanisms taking place under different scenarios, it is certain that more than one mechanism is actually supplementing each other in reducing the residual oil saturation while LSW flooding. This study has been undertaken investigations on the low saline flooding in unconsolidated Ottawa sandpack cores with two different, Weyburn & Pelican crude oil, to find out the optimum salinity, LSW Slug Size & underlying mechanisms during LSW flooding. Several core flooding experiments were performed under secondary as well as tertiary recovery stage by unsteady state method. With the reduction of brine salinity from 5000 PPM to 1500 PPM, the oil recovery increased in secondary stage & decreased further upon reduction in salinity to 500 PPM gaining the peak at 1500 PPM. Small enhancement in tertiary recovery of 2.24% observed upon switching to 1500 NaCl PPM brine after injection of formation brine in secondary stage for Weyburn Oil, though large tertiary recoveries of the order of 9.95% for effective oil viscosity of 4 cP and 7.32% for 29.7 cP were observed for n-dodecane diluted Pelican Oil. LSW slug size of 25% pore volume was found to be effective in producing Weyburn Oil in secondary stage.
