Sodium orthosilicate: An effective additive for alkaline steamflood
Steamflood performance often suffers from channelling and gravity segregation, resulting in poor sweep efficiency. Alkaline additives may be used with steam for certain types of crude oils to improve steamflood performance. In this paper, an experimental study is presented to evaluate the effectiveness of sodium hydroxide, sodium metasilicate and sodium orthosilicate for improving steamflood performance in the Wilmington Tar Zone crude oil. The experimental apparatus was designed to completely eliminate heat loss from the core so that the effects of the alkaline additives on saturated steam, rather than on the condensed water, could be studied. The results show that sodium orthosilicate outperforms sodium hydroxide and sodium metasilicate in enhancing oil recovery by a steamflood.
The lake sediments have registered the information of palaeoclimate and palaeoenvironment in the lake itself and the regional scale. This also leads to a complexity in study of the palaeolimnology by all kinds of proxies. How to purify these proxies to indicate the palaeoclimate has become a problem to be solved. Most of the proxies can qualitively identify the percentage of allochthonous and autochthonous organic components, e.g. δ13corg CD/TC. The model introduced in this note has provided a method of quantitatively calculating the amount of allochthonous organic carbon. As for determination of regulating parameters, i.e. A1 and As, further work is still in need.