CRYSTALLIZATION OF FORMING AGENT OF AGGLOMERATED CAKE AT LOW TEMPERATURE

This work aims to reveal the reasons of crystallization of forming agent of agglomerated cake (FAAC) at low temperature in order to improve the method of the FAAC storage at low temperature and enhance the promotion of the mud cake to agglomerated cake (MTA) method of cementing of oil and gas wells. It has been proved that the MTA method can improve the cementing quality of oil-gas well. However, FAAC used in this method tends to crystallize at low temperature, thus limiting its application and promotion. In this work, the comparative observation experiments combining with ion chromatography test are used to figure out the possible reasons for the crystallization of FAAC. It turns out that the low temperature is the main cause of crystallization of FAAC, where the precipitate is sodium sulfate hydrate. Further analysis suggests that the common-ion effect has a great influence on the stability of FAAC. Particularly, this research indicates the existence of strong hydrogen bond effect between sodium sulfate and sodium metasilicate, which is conducive to keeping the FAAC solution to stay stable at low temperature.