一种季铵盐双子表面活性剂自转向酸的变粘特性评价

长庆油田开发过程中地层CaCO_3垢引起堵塞造成油井产量下降,论文提出采用清洁无伤害的粘弹性表面活性剂自转向酸解除储层堵塞,并利用酸增粘形成暂堵屏障使后续酸分流转向改造未有效动用的低渗透油层。室内确定了一种自行合成的季铵盐双子表面活性剂自转向酸的主体配方:5%季铵盐表面活性剂15%盐酸。酸液最佳增粘温度在50～75℃;增粘后在170 s~(-1)下剪切2 700 s后粘度仍大于170 mPa·s;盐离子对酸液后期粘度的保持贡献的高低依次为Ca~(2+)>Na~+>Mg~(2+);高粘胶束遇原油等烃类能够自动破胶降粘,易返排对地层无伤害。该自转向酸适用于长庆油田三叠系和侏罗系的中低温、高矿化度油藏。

Investigation on viscidity behavior viscidity behavior of ammonium gemini surfactant aciding system

It is common for the decrease of oil production caused by plugging of CaCO_3 scale in Changqing oilfield.Using temporary plugging with high viscosity during acid—rock reaction in reservoir,the clean visco-elasticity surfactant diversion aciding system(VDA) is considered to remove scale in this paper.Meanwhlie,the low-permeability reservoir can be reconstructed by following aciding system because of temporary plugging.A ammonium gemini surfactant aciding system is made in laboratory.Experiments shows that system with 5%ammonium gemini surfactant and 15%HCl can get well visco-elasticity.The right temperature of increas ed viscosity is in the range of 50～75℃.Viscosity is above 170mPa.s with shear after 2 700 s in 170 s~(-1).Ca~(2+) is most useful to keep viscosity of aciding system,Na~+ is more useful,and Mg~(2+) is secondary.The high viscosity gel of aciding system is easy to break when mixing with oil.It is easy to backflow and not damaging to formation.The system applies to Triassic and Jurassic reservoir of high salinity and low-medium temperature in Changqing oilfield.