耐高温两性离子型油井水泥缓凝剂的合成及其缓凝机理研究

Study on Synthesis and Retarding Mechanism of High Temperature Resistant Oil Well Cement Retarder

为满足深井、超深井及地热井等复杂井况固井施工需求,综合分子结构设计思想和功能单体优选方法,以丙烯酰胺(AM)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)、马来酸酐(MAH)和二甲基二烯丙基氯化铵(DMDAAC)为聚合单体,通过水溶液聚合反应合成了耐高温两性离子型高分子聚合物类油井水泥缓凝剂HFB-2,粗产品产率约为82.7%。采用红外光谱分析、凝胶色谱分析及热重分析分别研究缓凝剂HFB-2化学结构、分子量大小、分子量分布和热稳定性。通过执行国标、行标探究缓凝剂HFB-2对水泥浆稠化时间、流变性能和抗压强度的影响。结合水泥浆水化产物物相分析和微观形貌分析研究了缓凝剂HFB-2的缓凝作用机理。研究结果表明:缓凝剂HFB-2具有较好的高温缓凝特性,高温220℃条件下缓凝剂HFB-2加量为1.2%(质量分数,下同)时,水泥浆稠化时间为312 min,24 h抗压强度大于14.0 MPa,主要通过吸附和络合作用抑制水化硅酸钙凝胶和Ca(OH)2晶体的生成,进而实现对油井水泥水化速率的有效控制。

In order to meet the cementing construction requirements of complex-well conditions such as deep wells,ultra-deep wells and geothermal wells,a high temperature resistant polymer oil well cement retarder HFB-2 was prepared through aqueous solution polymerization using AM,AMPS,MAH and DMDAAC as polymerization monomers by integrating molecular structure design ideas and functional monomer optimization methods,and the yield of crude product is about 82.7%.Firstly,the chemical structure,molecular weight size,molecular weight distribution and thermal stability of retarder HFB-2 were studied by infrared spectroscopy,gel chromatography and thermogravimetry.Moreover,the influence of retarder HFB-2 on the thickening time,rheological property and compressive strength of cement slurry was investigated respectively according to the relevant national standards and industrial standards.Finally,the retarding mechanism of retarder HFB-2 was analyzed by phase analysis and microscopic morphology analysis of cement slurry hydration products.The research results show that the retarder HFB-2 has good high temperature retarding characteristics,when its dosage is 1.2%at high temperature of 220℃,the thickening time of cement slurry is 312 min,and the compressive strength in 24 hours is more than 14.0 MPa.It mainly inhibits the formation of hydrated calcium silicate gel and calcium hydroxide crystal through adsorption and complexation,and then effectively controls the hydration rate of oil well cement.