响应面法优化两亲聚合物缓凝剂温度响应特性

Optimization of Preparation of Amphiphilic Polymer as High Temperature Retarder and Intelligent Control of Thickening Time of Cement Slurry by Response Surface Methodology

针对深井长封固段固井面临的高温大温差环境,缓凝剂难以同时满足深井高温泵送时间长、顶部低温候凝时间短的要求,依据两亲聚合物自组装结构形成/解离过程中的分子构效变化原理,采用2-丙烯酰胺-2-甲基苯磺酸(AMPS)、丙烯酸(AA)、多元不饱和羧酸(PA)、阳离子单体(CM),通过可逆加成链转移法制备出两亲聚合物缓凝剂TRIR,利用响应面法优化了缓凝剂的温度响应智能调控特性,确定了缓凝剂TRIR较佳合成条件:单体浓度占比为28.7%、引发剂用量为0.6%、合成温度为50℃、反应pH值为4.5。评价结果表明,两亲聚合物缓凝剂TRIR耐温性能优异,4.0%(液体)加量下200℃高温稠化时间达356 min,在120~180℃范围内随温度升高缓凝性能显著增强,高温大温差下顶部水泥浆强度发展快,无超缓凝不良现象,可将候凝时间缩短到24 h,为深井高温大温差固井和未来智能型缓凝剂的发展提供新思路。

Cementing in long sealing section of deep well is faced with the problem of long thickening time in high temperature section and long solidification time in low temperature section.Based on the concept of molecular structure activity changes during the formation/dissociation of amphiphilic polymer self-assembly structure.AMPS,unsaturated carboxylic acid(PA)and cationic monomer(CM)are used to synthesis a temperature responsive intelligent retarder TRIR by RAFT polymerization.Response surface methodology was used to optimize the synthetic process conditions of the polymer.The optimal process conditions were determined as follows:monomer concentration 28.7%,initiator dosage 0.6%,synthesis temperature 50℃,and reaction pH 4.5.The structure and thermal stability of the polymer were characterized by infrared spectroscopy and thermogravimetric analysis,and its retarding performance was evaluated.The results show that TRIR has excellent temperature resistance,the thickening time at 200℃can reach 356 min under 4.0%(liquid)dosage,and the retarding property is significantly enhanced with the temperature rise in the range of 120~180℃.The thermal response polymer proposed in this paper can provide a new idea for the development of intelligent polymer in the future petrochemical field.