羟乙基羧甲基纤维素与金属离子交联作用机理

Crosslinking Mechanism of Hydroxyethyl Carboxymethyl Cellulose and Metal Lons

纤维素作为丰富的可再生资源,在储层改造领域具有广阔的应用前景。纤维素压裂液近两年在气井压裂上的先导试验也取得了较好的增产效果。通过实验,对其稠化剂羟乙基羧甲基纤维素与高价金属离子的交联作用机理进行了研究。结果表明,该纤维素交联凝胶点的时间与频率无关,与交联剂浓度关系密切。在优化压裂液配方时,可根据需要调节交联时间;羟乙基羧甲基纤维素与高价金属离子交联即存在化学交联,同时也存在物理交联,纤维素分子链上的羟基同交联剂配位体中的羟基或有机锆中的离子产生强烈的氢键作用,形成物理交联点;纤维素分子链上的羧酸根同交联剂中的金属离子形成化学交联点。

Cellulose has broad application prospects in the field of reservoir reconstruction because of abundant renewable resources. Cellulose fracturing fluid applications on gas wells also achieved good production effect in the past two years. Through the experiments crosslinking mechanism of hydroxyethyl carboxymethyl cellulose and high metal Ions were studied. The results show that the cellulose crosslinked gel point time has nothing to do with the frequency,which closely associated with concentration of crosslinking agent. So crosslinking time can be adjusted in optimizing of fracturing fluid formula according to demand. There are chemical crosslinking and physical crosslinking in crosslinking mechanism of hydroxyethyl carboxymethyl cellulose and high metal ions. Hydroxyl groups of cellulose molecular chain produce strong hydrogen bonding interaction with hydroxyl groups or organic zirconium ions of crosslinking agent,which forming the physical junction. Chemical crosslinking junctions were produced in carboxylic acid root of cellulose molecular chain with the metal ions of crosslinking agent.