用于中低渗油藏的表面活性聚合物驱油剂

Surface active-polymer flooding agent for medium and low permeability reservoir

以表面活性单体N-十六烷基-N-磺基丙烯酰胺(NS)、丙烯酰胺(AM)为原料,采用水溶液自由基聚合法制备了低相对分子质量的表面活性聚合物(PAS)。利用FTIR对其进行了结构表征,考察了PAS作为驱油剂的增黏、乳化、注入、提高采收率相关性能。在45℃、NaCl矿化度为2410 mg/L条件下,质量浓度为1000 mg/L的PAS溶液表观黏度为32.6 mPa·s,高于相对分子质量为8.0×10^(6)的部分水解聚丙烯酰胺(HPAM,18.9 mPa·s);在PAS质量浓度为1000 mg/L的条件下,其与原油形成的乳液120 min析水率为5.0%,3次吸附后表观黏度保留率为114.11%,吸附后仍具有较好的乳化性;在渗透率为0.025μm^(2)的岩心中注入平稳压力为1.02 MPa;在岩心渗透率为0.1μm^(2)的条件下,PAS驱能在水驱基础上提高采收率19.02%,比HPAM驱高5.00%,与HPAM-碳酸钠-石油磺酸钠三元体系提高采收率相当,仅低0.58%。

Surfactant-polymer(PAS)with relative low molecular mass was prepared from free radical polymerization of surfactant monomer N-hexadecyl-N-sulfoacrylamide(NS)and acrylamide(AM),characterized by FTIR,and was investigated as an oil displacement agent for analysis on the related properties such as viscosity increase,emulsification,injection and enhanced oil recovery.At 45℃and NaCl degree of mineralization of 2410 mg/L,PAS solution with a mass concentration of 1000 mg/L displayed an apparent viscosity of 32.6 mPa·s,which was higher than that of partially hydrolyzed polyacrylamide(HPAM)with a relative molecular mass of 8.0×10^(6)(18.9 mPa·s).Meanwhile,the water dissolution rate of emulsion formed from PAS and crude oil was 5.0%in 120 min,and the apparent viscosity retention rate after three adsorptions was 114.11%,showing good emulsification capacity after adsorption.The stable injection pressure was 1.02 MPa at the standstone core with a permeability of 0.025μm^(2).When the core permeability was 0.1μm^(2),PAS flooding improved oil recovery by 19.02%over water flooding,5.00%over flooding by HPAM flooding and comparable to flooding by HPAM-sodium carbonate-sodium petroleum sulfonate system,only 0.58%lower.