高温固井水泥浆用降失水剂GT-1的制备及性能

Preparation and Application of Fluid Loss Additive GT-1 for High Temperature Cementing Slurry

随着油气勘探向深井、超深井方向的不断发展,固井作业对其工作液体系及外加剂提出了更高要求。针对目前降失水剂耐温、抗盐性能不足、适应温度范围窄、且与其他外加剂相容性差等问题,基于分子结构设计思想并结合功能单体优选,以2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、丙烯酰胺(AM)、对苯乙烯磺酸钠(SSS)、纳米二氧化硅等为原料制备了高温固井水泥浆用降失水剂GT-1。采用红外光谱、凝胶色谱、热综合及扫描电镜等分析方法研究了其化学结构、分子量、热稳定性及水溶液微观形貌。并对GT-1的失水性能、耐温性能、抗盐性能及所配制水泥浆体系的流变性能、抗压强度和稠化性能进行了研究。结果表明,降失水剂GT-1化学结构符合预期设计,重均相对分子质量为138431,热稳定性优良,且其水溶液呈现规整的空间网状结构;同时,降失水剂GT-1耐温、抗盐性能突出,能够控制水泥浆失水量,且所配制水泥浆工程性能良好,满足固井施工需求,具有较好的应用前景。

In exploration of deep and ultra-deep buried oil and gas resources,well cementing operation has long imposed more rigorous requirements on cement slurries and additives.Filter loss reducers commonly used in cement slurries,for example,have some shortages such as poor high-temperature and salt resistance,narrow temperature range in which the filter loss reducers can work,as well ss poor compatibility with other additives.To solve these problems,a high temperature filter loss reducer GT-1 was developed based on the design of molecular structure and the selection of functional monomers,with raw materials such as 2-acrylamido-2-methylpropane sulfonic acid(AMPS),acrylamide(AM),sodium p-styrene sulfonate(SSS)and nano silica.Using IR,gel chromatography,simultaneous thermal analyzer and SEM,the filtration control,high temperature resistance and salt resistance of GT-1,as well as GT-1’s effect on the rheology of cement slurry,the compressive strength of set cement and consistency of cement slurry were studied.The study showed that the chemical structure of GT-1 meets the requirements previously planned.The weight average molecular weight of GT-1 is 138,431,and GT-1 has excellent thermal stability.A regular spatial network structure can be measured in GT-1’s water solution.Good high temperature and salt resistance of GT-1 makes it suitable for controlling the filtration rate of cement slurry.Cement slurries formulated with GT-1 have good engineering performance which satisfies the needs of well cementing.