低温抗盐降失水剂LTF-1的室内合成及性能研究

针对低温浅层、盐层油气井固井水泥浆存在低温强度发展缓慢、受盐层影响较大的问题,依据自由基水溶液聚合原理,制备出一种低温抗盐降失水剂LTF-1.LTF-1是利用AMPS、AM和一种单体X通过共聚反应制备而成,采用正交实验法,确定单体配比、优化分子结构、调整相对分子质量大小及其分布,优选出LTF-1的最佳合成工艺条件.室内研究表明,以LTF-1为主剂的低温水泥浆体系具有强度发展迅速、失水量低、抗盐能力强、流变性优异、缓凝性弱及稠化时间易调等特点,解决了常规降失水剂固井水泥浆存在低温强度发展缓慢、受盐层影响较大的问题;其综合性能能够满足低温浅层及盐层油气井的固井要求.

Laboratory Synthesis and Performance Research of Low-Temperature and Salt-Resistant Fluid Loss Additive LTF-1

In consideration of the problems of low-temperature,shallow and salt-deposit cementing slurry of oil and gas wells,a style of low-temperature and salt-resistant fluid loss additive LTF-1 was synthetized by free radical polymerization in aqueous solution in order to solve the problems of tardy development of compressive strength and intensive influence of salt-layer. Fluid loss additive LTF-1 is a multi-component copolymer synthesized by copolymerization of 2-acrylamido-2-methylpropane sulfonic acid（AMPS）,acrylamide（AM）and a monomer X. Optimal synthesizing process conditions of LTF-1 were extracted by orthogonal experiment,which was achieved by controlling the mass ratio of monomers,optimizing molecular structure,and adjusting the molecular weight size and distribution.Experimental results show that cement slurry system with LTF-1 has the characteristics of swift development of compressive strength, low filtration, good salt-resistance, optimal rheological behavior, weak setting retarding effect,and easily-adjustable thickening time as well as short transit time. In the circumstance of low-temperature,the problems of the cement slurry with conventional fluid loss control agent have been solved. Comprehensive performance of the cement slurry with fluid loss additive LTF-1 can satisfy the requirement of cementing of lowtemperature shallow layer as well as salt-bed oil and gas well.