The Alaska North Slope(ANS)is endowed with a substantial reservoir of heavy oil,estimated at 12-18billion barrels,primarily concentrated within the Ugnu reservoirs.These deposits,situated at depths ranging from 2000 t...The Alaska North Slope(ANS)is endowed with a substantial reservoir of heavy oil,estimated at 12-18billion barrels,primarily concentrated within the Ugnu reservoirs.These deposits,situated at depths ranging from 2000 to 4000 feet,lie in close proximity to the permafrost and have undergone biodegradation,resulting in in-situ viscosities reaching thousands of centipoise.Following the success in recovering the somewhat less heavy,viscous oils through polymer injection,the deposits in Ugnu Formation are garnering significant interest.Although thermal recovery methods are commonplace for heavy oils,applying these methods on ANS is impractical,given the adjacency to continuous permafrost.Therefore,non-thermal hybrid enhanced oil recovery(cEOR)methods,such as solvent(e.g.,CO_(2))and low salinity water(LSW),or LSW and polymer-based techniques,emerge as the primarily feasible options for recovering these vast heavy oil resources.This study experimentally investigates,via systematically carried out fluid property and phase behavior tests and a series of sand-pack coreflood experiments,the potential to enhance the recovery of Ugnu heavy oils.The coreflood experiments reveal the synergistic effect of combining liquid-CO_(2)with LSW to be the most promising approach in this study as a water alternating gas(WAG)process results in the cumulative recovery factor of 83.5%,doubling the recovery obtained by continuous low salinity waterflood.Additionally,the liquid-CO_(2)-LSW WAG process demonstrated an additional benefit for CO_(2)storage,with about 25%of the pore volume of the liquid-CO_(2)injected being sequestered at the end of the injection process.This significant recovery improvement is attributed to a substantial reduction of oil viscosity upon contact with the liquid CO_(2)during the soaking period,with a reduction of up to 95%of the original oil viscosity.Meanwhile,in-situ emulsion generation was observed in the oil produced from the continuous LSW flooding.This was also evident by the increased differential pressure across the sand-pack compared to that of the liquid-CO_(2)alternating LSW process.The promising results of this study indicate significant potential for liquid-CO_(2)alternating LSW injection as an effective cEOR technique for Ugnu heavy oils.展开更多
阿拉斯加Milne Point Unit产自Kuparuk，Schrader和Ugnu地层。Kup础地层中有轻质油（3cp）。Schrader地层中油的粘度为20-200cp。在Ugnu地层中发现了最稠的油，其粘度为200cp-2000多cp。在Ugnu地层蕴含有油田的最大石油地质储量（OIP）...阿拉斯加Milne Point Unit产自Kuparuk，Schrader和Ugnu地层。Kup础地层中有轻质油（3cp）。Schrader地层中油的粘度为20-200cp。在Ugnu地层中发现了最稠的油，其粘度为200cp-2000多cp。在Ugnu地层蕴含有油田的最大石油地质储量（OIP）。现在，BP公司正在寻找一种在Milne商业性开采Ugnu地层的方法。展开更多
基金financial support for this study and the Petroleum Development Laboratory(PDL)at University of Alaska Fairbanks(UAF)for allowing the use of the facilities。
文摘The Alaska North Slope(ANS)is endowed with a substantial reservoir of heavy oil,estimated at 12-18billion barrels,primarily concentrated within the Ugnu reservoirs.These deposits,situated at depths ranging from 2000 to 4000 feet,lie in close proximity to the permafrost and have undergone biodegradation,resulting in in-situ viscosities reaching thousands of centipoise.Following the success in recovering the somewhat less heavy,viscous oils through polymer injection,the deposits in Ugnu Formation are garnering significant interest.Although thermal recovery methods are commonplace for heavy oils,applying these methods on ANS is impractical,given the adjacency to continuous permafrost.Therefore,non-thermal hybrid enhanced oil recovery(cEOR)methods,such as solvent(e.g.,CO_(2))and low salinity water(LSW),or LSW and polymer-based techniques,emerge as the primarily feasible options for recovering these vast heavy oil resources.This study experimentally investigates,via systematically carried out fluid property and phase behavior tests and a series of sand-pack coreflood experiments,the potential to enhance the recovery of Ugnu heavy oils.The coreflood experiments reveal the synergistic effect of combining liquid-CO_(2)with LSW to be the most promising approach in this study as a water alternating gas(WAG)process results in the cumulative recovery factor of 83.5%,doubling the recovery obtained by continuous low salinity waterflood.Additionally,the liquid-CO_(2)-LSW WAG process demonstrated an additional benefit for CO_(2)storage,with about 25%of the pore volume of the liquid-CO_(2)injected being sequestered at the end of the injection process.This significant recovery improvement is attributed to a substantial reduction of oil viscosity upon contact with the liquid CO_(2)during the soaking period,with a reduction of up to 95%of the original oil viscosity.Meanwhile,in-situ emulsion generation was observed in the oil produced from the continuous LSW flooding.This was also evident by the increased differential pressure across the sand-pack compared to that of the liquid-CO_(2)alternating LSW process.The promising results of this study indicate significant potential for liquid-CO_(2)alternating LSW injection as an effective cEOR technique for Ugnu heavy oils.
文摘阿拉斯加Milne Point Unit产自Kuparuk，Schrader和Ugnu地层。Kup础地层中有轻质油（3cp）。Schrader地层中油的粘度为20-200cp。在Ugnu地层中发现了最稠的油，其粘度为200cp-2000多cp。在Ugnu地层蕴含有油田的最大石油地质储量（OIP）。现在，BP公司正在寻找一种在Milne商业性开采Ugnu地层的方法。
