Comprehensive treatment of gas channeling at the later stage of CO2 flooding
Online published: 2014-10-20
It is difficult for the field to achieve the CO2 miscible flooding efficiency of indoor experiments which could reach more than 90%. Recovery factor is limited mainly by several aspects, namely, CO2 viscous fingering, gravity overlap and reservoir heterogeneity, which exert negative influence on CO2 sweep efficiency. On the other hand, gas channeling aggravates gradually and development conflicts intensify continuously at the later stage of production. This paper analyzed development effect of CO2 flooding, regarding layer series of development, injection-production structure, way of injection and injection profile, moreover, proposed technologies of strata subdivision, injection in the top, water alternating gas(WAG), polymer profile control and CO2+foam flooding. Good response has been observed after the onsite implementation. Reservoir overall gas-oil ratio decreased from 2 733.1 m3/m3 to 63.84 m3/m3, and daily oil production increased from 30.72 t(before gas injection) to 81.68 t(after gas injection). Generally, this anti-gas channeling comprehensive technology is of great significance for similar reservoir scenario design and gas channeling prevention.
WU Siyi , SIMA Liqiang , YUAN Long , WEN Xinfang . Comprehensive treatment of gas channeling at the later stage of CO2 flooding[J]. Lithologic Reservoirs, 2014 , 26(5) : 102 -106 . DOI: 10.3969/j.issn.1673-8926.2014.05.019
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