弱凝胶钻井液成胶剂AM/AMPS/OA_8的合成与表征

Synthesis and Characterization of A Weak Gel Gelling Agent AM/AMPS/OA_8 in Water-based Drilling Fluid

针对水平井、大斜度井钻井过程中井眼润滑性、岩屑携带以及钻井速度的影响等问题,通过合理的分子设计,以丙烯酰胺(AM)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)和实验室自制疏水单体丙烯酸正辛醇OA_8为原料,利用胶束聚合法,制备了一种弱凝胶成胶剂AMAMPSOA_8,其结构经1H NMR和IR表征。以AMAMPSOA_8在低剪切速率下的表观粘度为指标设计正交试验,确定最优反应条件为:AM与AMPS摩尔配比为4.8∶1,引发剂用量为单体总质量的0.04%,疏水单体浓度为0.75%,于70℃反应9 h。该条件下,0.5%AMAMPS0A_8聚合物溶液在低剪切速率3 r·min^(-1)下表观粘度可达23 680 mPa·s。利用热分析仪、高温滚子炉、高温高压流变仪对产物性能进行了研究。研究表明:AMAMPSOA_8的抗温性能可达160℃;聚合物溶液体系有明显的触变性,在40 min后溶液切力增加幅度变缓。

Facing with the problems of borehole lubrication, cuttings transportation and drilling speed in the drilling processes of horizontal wells and highly-deviated wells, a kind of weak gel gelling agent （ AMAMPSOAs ） was successfully synthesized by reasonable design of molecular structure and micellar polymerization, using acrylamide （ AM）, 2-acrylamide-2-methylpro panesulfonic acid （ AMPS ） and the hydrophobic monomer OAs which was made in laboratory as raw materials. The structure was character- ized by 1H NMR and FT-IR. Setting the apparent viscosity of AMAMPSOAs at the low shear rate as in- dex, orthogonal experiments were designed to determine the optimal reaction conditions： molar ratio of AM and AMPS was 4.8 ： 1 , the mass fraction of initiator was 0.04% , the concentration of hydropho- bic monomer was 0.75%, reaction at 70 % for 9 h. Under this condition, the apparent viscosity of AMAMPSOAs at the low shear rate （3 r · min- 1 ） was 23 680 mPa · s. The performance was studied by the thermal analyzer, high temperature roller furnace and HAAKE rheometer. The results showed that the polymer solution system exhibited obvious thermal property up to 160 ℃ and thixotropic property, the shear strength increased slowly after 40 min.