反相乳液聚合法制备钻井液抗温增黏提切剂及其性能评价

SYNTHESIS OF TEMPERATURE-RESISTANT VISCOSIFIER BY REVERSED-PHASE EMULSION POLYMERIZATION AND EVALUATION OF ITS PERFORMANCE IN DRILLING FLUID

选用2-甲基-2-丙烯酰胺基丙磺酸(AMPS)、N,N-二甲基丙烯酰胺(DMAM)丙烯酰胺(AM)、N-乙烯基吡咯烷酮(NVP)和功能单体(SST)为反应单体,采用反相乳液聚合法制备了钻井液抗温增黏提切剂VIS-F。通过正交实验对油水比、乳化剂加量、引发剂加量、单体配比等反应条件进行了优化,分别采用红外光谱和乌式黏度计对增黏剂进行了分子结构表征和特性黏数测定,对其在淡水、盐水、饱和盐水和复合盐水基浆中的抗温增黏性能进行了评价,并利用大斜度井井眼净化模拟装置对VIS-F的携岩性能进行了实验评价。结果表明:VIS-F在淡水、盐水基浆和饱和盐水、复合盐水基浆中均具有较好的抗温、增黏提切性能,180℃老化后,VIS-F在淡水、盐水钻井液基浆中的粘切保持率均达76%以上;160℃老化后,VIS-F在饱和盐水、复合盐水钻井液基浆中的粘切保持率均达70%以上。在低环空排量下,增黏提切剂VIS-F在钻井液基浆中的携岩效率达85%以上,优于传统钻井液增黏剂80A51。

A high temperature resistance viscosifier for water-based drilling fluid,denominated as VIS-F,was synthesized by inverse emulsion polymerization of 2-methyl-2-acrylamido-propanesulfonic acid(AMPS),N-dimethylacrylamide(DMAM)acrylamide(AM),N-vinylpyrrolidone(NVP),and functional monomer(SST).The reaction parameters were optimized by orthogonal test,including oil-water ratio,emulsifier dosage,initiator dosage,and monomer ratio.The molecular structure of VIS-F was confirmed by Fourier transform infrared spectroscopy(FT-IR),while the intrinsic viscosity was measured by Ubbelohde viscometer.The temperature resistance of VIS-F was evaluated in freshwater,brine-based,saturated brine-based,and salt composite-based fluids.The cuttings carrying capacity of VIS-F was evaluated using a highly deviated well simulation device.It was found that VIS-F exhibits good temperature resistance and enhanced thickening and shear properties in freshwater,brine-based,saturate-brine and salt composite-based fluids.The viscosity retention rates in both freshwater and brine-based fluids are above 76%after hot rolling at 180℃.Moreover,the viscosity retention rates in both saturated-brine and salt composite-based fluids are above 70%after heat treatment at 160℃.In addition,the drilled cuttings carrying test revealed that VIS-F provides an excellent carrying capacity under low annular flow with a carrying efficiency of more than 85%,which is better than that of the conventional viscosifier 80A51.