甜菜碱/AOS/Gemini季铵盐三元复合型泡排剂的研制与性能评价

Preparation and performance of betaine/AOS/Gemini ternary surfactant foam for gas well deliquification

泡沫排液技术是保障气井产量的重要手段,研发高性能的泡排剂极其关键。为适应高矿化度、高凝析油含量及高温等苛刻气井环境,以椰油酰胺丙基羟基磺基甜菜碱(CHSB)作为主剂,α-烯基磺酸钠(AOS)和合成的Gemini阳离子表面活性剂CAGB作为辅剂制备了一种高效环保的三元泡排体系。结果表明,三元复配体系AOS/CAGB/CHSB在摩尔比为12∶3∶35、总量为20 mmol/L时性能最优,泡沫体积和半衰期分别达到360 mL和30.27 min;在含有30%甲醇的泡排剂溶液中,测得的携液率最高可达31%,发泡率为95%;在含有0%~50%凝析油的泡排剂溶液中,三元泡沫体系表现出良好的性能,其中在凝析油含量为20%时,测得的携液率最高可达38%,发泡率为95%;优选的三元复配体系AOS/CAGB/CHSB对盐离子耐受性较差,加入螯合剂(氨三乙酸三钠(NTA))后,三元复配体系在矿化度为150 g/L的溶液中仍能稳定发泡和携液;温度大于50℃时,泡沫的携液率也逐渐增加,温度在90℃时,携液率在95%以上。此外,通过表面张力测试、泡沫微观结构观察也证实了该泡排剂体系存在的协同效应使其起泡、稳泡和泡沫携液能力得到有效提升。

Foam-based deliquification is important to ensure the production of gas wells,therefore,there is no doubt that the development of high�performance foaming agents is extremely critical for the gas wells with high salinity,high condensate oil content and high temperature.For this reason,a highly efficient and environmentally friendly ternary foaming mixture was prepared by coconut oil amide propyl hydroxy sulfobetaine(CHSB),sodiumα-olefin sulfonate(AOS)and synthetic Gemini cationic surfactant(CAGB)in this study.The results showed that the AOS/CAGB/CHSB mixture had the best performance when the molar ratio was 12∶3∶35 at the total amount of 20 mmol/L.The foam volume and half-life reached 360 mL and 30.27 min,respectively.In the foaming agent solution containing 30%methanol,the measured liquid unloading efficiency was 31%,and the foaming efficiency was 95%.With 0%-50%condensate oil,the ternary foaming mixture showed good performance.With 20%condensate oil,the liquid unloading efficiency was up to 38%and the foaming efficiency was 95%.The optimized AOS/CAGB/CHSB exhibited poor tolerance to salt ions.However,with trisodium aminotriacetate(NTA),the ternary complex system was still effective at a salinity of 150 g/L.At temperatures higher than 50℃,the liquid unloading efficiency of the foam also gradually increased,and the liquid unloading efficiency was above 95%at 90℃.In addition,the surface tension test and foam microstructure observation also confirmed the presence of synergy in foaming,foam stabilization and foam liquid unloading.