Authors: Byung In Choi, Moon Sik Jeong, Kun Sang Lee
Abstract: Water salinity and hardness have been regarded as main limitation for field application of polymer floods. It causes not only reduction of polymer concentration, but also injectivity loss in the near wellbore. Based on the mathematical and chemical theory, extensive numerical simulations were conducted to investigate performance of polymer floods in the high-salinity reservoirs. According to results from simulations, the high salinity reduces the viscosity of polymer in contacting area. That causes a poor sweep efficiency of polymer flooding. Moreover, the presence of divalent cations makes the project of polymer flooding worse. That is because of excessively increased bottom-hole pressure in injection well by the precipitation of polymer. The quantitative assessment of polymer floods needs to be required before field application. Therefore, the results in this paper are helpful for optimal polymer flooding design under harsh reservoir conditions.
2607
Authors: Ji Chao Fang, Cai Li Dai, Kai Wang, Qin Fang Ding, Si Yu Wang
Abstract: In order to further enhance oil recovery (EOR) of the high temperature and high salt oil fields by foam flooding, one foaming agent was screened by airflow method. The influence of oil-water and pressure on foamability and stability were evaluated,and oil displacement experiment was also conducted. The results show that CS-1 foaming agent has better foamability and stability than the others under the reservoir conditions (Temperature 110 °C, Salinity 11.52×104 mg/L, Ca2+&Mg2+ 7654 mg/L). The foam stability will be better as the pressure rise or be worse when it met the crude oil. Oil recovery was improved by 4.13% after waterflood and the total recovery is 60.75%.
82
Authors: Quan Tian, Ling Hui Sun, Hui Hui Kou
Abstract: At present, China's late stage of oilfield most mining has been reached, there is high water content, and produced low levels problems. Polymer flooding enhanced oil recovery technology is important today, but Pam can't adapt oilfield tertiary oil recovery reservoir with heat resistance and salt. This article examines five kinds of rheological properties of polymer solutions under different salinity, studied under the same mineralized shear viscosity of different polymers. Experimental results show that the shear resistance capacity of 20 million ordinary polymer strong, 8 million and temperature of salt-tolerant associative polymer viscosity retention rates are highest. Less than 5,000 ppm 18 million under NaCl salinity salt resistant polymer viscosity highest salinity between 5,000 ppm NaCl to 15,000 ppm NaCl 8 million and temperature of salt-tolerant hydrophobically associating polymer solution viscosity of the highest.
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