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Technologies and practice of CO2 flooding and sequestration in China
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HU Yongle,HAO Mingqiang,CHEN Guoli,SUN Ruiyan,LI Shi
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Table 2 Injection-production design and adjustment parameters of CO2 flooding in low-permeability oil reservoirs.
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Develop-
ment stage | Timing for turning to CO2 injection | CO2 injection
rate | Pressure maintenance level relative to original formation pressure/% | Cumulative
injection-production ratio | HC Pore volume multiple of injected CO2 | Bottom hole flowing pressure level relative
to original formation pressure/% | Gas-oil ratio/
(m3·t-1) | Water-gas alternation ratio | Energy
recovery | Water cut <90% | Fast injection
of CO2 | | | <0.05 | | | | | Miscible | | Mild injection
of CO2 | 100-120 | 1.5-1.8 | 0.15-0.50 | 110-120 | 400-
500 | 1:1 or 1:2 | Overall
breakthrough
of CO2 | | Mild injection
of CO2 | 100-120 | 1.5 | 0.50-1.00 | >120 | 500-
1 000 | 2:1 (small cycle) |
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