含孪尾结构两性离子共聚物的合成及性能

以丙烯酰胺(AM)、丙烯酸(AA)、N,N-二辛基甲基丙烯酰胺(DLMB)和3-(2-甲基丙烯酰胺丙基二甲胺基)丙磺酸盐(MDPS)为单体,通过自由基共聚,制备了一种含孪尾结构的两性离子共聚物驱油剂(AADM)。对共聚物进行了红外、核磁表征并确认了其结构,热重实验分析了热稳定性,并与部分水解聚丙烯酰胺(HPAM)进行了对比,考察了该共聚物的增黏性、水溶性、抗老化、剪切稀释性、剪切恢复性和耐温抗盐性。结果表明,共聚物AADM具有优异的水溶性和增黏性,在2000 mg/L的质量浓度下可使表观黏度达到466.5 mPa·s;在510s–1的剪切速率下,其表观黏度为60.4 mPa·s;在120℃下,其表观黏度能够达到182.6 mPa·s;在经过30 d的老化实验后其表观黏度为94.6 mPa·s;在15000 mg/L NaCl、2000 mg/L MgCl_2和2000 mg/L CaCl_2溶液中,该共聚物的表观黏度分别为77.8、72.4和68.6 mPa·s。在岩心驱替实验中,共聚物溶液能够将采收率提高7.72%。以上实验结果均优于相同条件下的HPAM,这是因为孪尾结构的引入有效地增强了共聚物的疏水缔合能力,两性离子单体的引入削弱了分子链对盐的敏感度。

Synthesis and Properties of a Zwitterionic Copolymer Containing Twin-Tail Structure

A zwitterionic copolymer (ANND) containing twin-tail structure was synthesized using acrylamide (AM), acrylic acid (AA), N,N-dioctylmethacrylamide (DLMB) and 3-(2-methacrylamidopropyldimethylamino)propane sulfonate (MDPS) via free-radical copolymerization. The copolymer was characterized by FT-IR, 1H NMR and TG-DTG to confirm that it was prepared successfully and had favorable thermal stability. And compared with partially hydrolyzed polyacrylamide (HPAM), the thickening property, water solubility, aging resistance, shear thinning, temperature tolerance and salt resistance of the copolymer were investigated. The results showed that the copolymer had excellent water solubility and thickening property, and its apparent viscosity could reach 466.5 mPa·s at 2000 mg/L. The apparent viscosity of the copolymer could remain 60.4 mPa·s under 510 s-1 and 182.6 mPa·s at 120 oC. And the viscosity retention value of AADM could remain 94.6 mPa·s after 30 days of aging. When the copolymer was dissolved in 15000 mg/L NaCl, 2000 mg/L MgCl2 and 2000 mg/L CaCl2 solutions, the apparent viscosity of these copolymer solutions were 77.8, 72.4 and 68.6 mPa·s, respectively. Core flooding experiment further indicated that the copolymer solution could enhance oil recovery by 7.72%. The above experimental results are superior to those of HPAM under the same conditions, because the introduction of the twin-tail structure effectively enhances the hydrophobic association ability of the copolymer, and the introduction of the zwitterionic monomer weakens the sensitivity of the molecular chain to the salt.