Since pure foaming agent with short half-value period causes a poor plugging effect for high-permeability reservoir with water channeling, this paper studies on gel foam sysem.

针对纯发泡剂半衰期较短、对已形成注入水窜流通道的高渗透储层封堵效果较差的实际问题，开展了凝胶泡沫体系的研究。

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In a relatively short period of time, the stock lost half its value and languished for years.

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In the first half of 2004 (the latest period for which figures are available) the value of sales fell by 1.3% compared with the first six months of 2003, according to the IFPI, a recording industry body, largely thanks to piracy.

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The value of digital fiction sales in the first half of 2012 was up 188% on the same period in 2011.

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