The effective development of unconventional tight oil formations,such as Bakken,could include CO_(2) enhanced oil recovery(EOR)technologies with associated benefits of capturing and storing large quantities of CO_(2)....The effective development of unconventional tight oil formations,such as Bakken,could include CO_(2) enhanced oil recovery(EOR)technologies with associated benefits of capturing and storing large quantities of CO_(2).It is important to conduct the gas injection at miscible condition so as to reach maximum recovery efficiency.Therefore,determination of the minimum miscibility pressure(MMP)of reservoir live oileinjection gas system is critical in a miscible gas flooding project design.In this work,five candidate injection gases,namely CO_(2),CO_(2)-enriched flue gas,natural gas,nitrogen,and CO_(2)-enriched natural gas,were selected and their MMPs with a Bakken live oil were determined experimentally and numerically.At first,phase behaviour tests were conducted for the reconstituted Bakken live oil and the gases.CO_(2) outperformed other gases in terms of viscosity reduction and oil swelling.Rising bubble apparatus(RBA)determined live oileCO2 MMP as 11.9 MPa and all other gases higher than 30 MPa.The measured phase behaviour data were used to build and tune an equation-of-state(EOS)model,which calculated the MMPs for different live oilgas systems.The EOS-based calculations indicated that CO_(2) had the lowest MMP with live oil among the five gases in the study.At last,the commonly-accepted Alston et al.equation was used to calculate live oilepure CO_(2) MMP and effect of impurities in the gas phase on MMP change.The Bakken oile CO_(2) had a calculated MMP of 10.3 MPa from the Alston equation,and sensitivity analysis showed that slight addition of volatile impurities,particularly N_(2),can increase MMP significantly.展开更多
基金The authors acknowledge the financial support from the Petroleum Technology Research Centre(PTRC)and the participating oil companies in the PTRC's STEPS(Sustainable Technologies for Energy Production Systems)program.The authors also wish to express their appreciation to Danie Subido,Kevin Rispler,and Rupan Shi for carrying out the experimental measurements,and to Brenda Tacik for editorial support.
文摘The effective development of unconventional tight oil formations,such as Bakken,could include CO_(2) enhanced oil recovery(EOR)technologies with associated benefits of capturing and storing large quantities of CO_(2).It is important to conduct the gas injection at miscible condition so as to reach maximum recovery efficiency.Therefore,determination of the minimum miscibility pressure(MMP)of reservoir live oileinjection gas system is critical in a miscible gas flooding project design.In this work,five candidate injection gases,namely CO_(2),CO_(2)-enriched flue gas,natural gas,nitrogen,and CO_(2)-enriched natural gas,were selected and their MMPs with a Bakken live oil were determined experimentally and numerically.At first,phase behaviour tests were conducted for the reconstituted Bakken live oil and the gases.CO_(2) outperformed other gases in terms of viscosity reduction and oil swelling.Rising bubble apparatus(RBA)determined live oileCO2 MMP as 11.9 MPa and all other gases higher than 30 MPa.The measured phase behaviour data were used to build and tune an equation-of-state(EOS)model,which calculated the MMPs for different live oilgas systems.The EOS-based calculations indicated that CO_(2) had the lowest MMP with live oil among the five gases in the study.At last,the commonly-accepted Alston et al.equation was used to calculate live oilepure CO_(2) MMP and effect of impurities in the gas phase on MMP change.The Bakken oile CO_(2) had a calculated MMP of 10.3 MPa from the Alston equation,and sensitivity analysis showed that slight addition of volatile impurities,particularly N_(2),can increase MMP significantly.
