摘要
粘弹性表面活性剂VES 70压裂液由复配表面活性剂VES 70和粘土稳定剂组成 ,其中VES 70为C16、C18烷基三甲基季铵盐与有机酸、异丙醇等的复配物。实验考察了VES 70胶束凝胶压裂液的应用性能。在 30℃下 ,VES 70溶液的表观粘度 (170s-1)随VES 70体积分数的增加而增大并趋于恒定值 :2 %溶液为 5 7mPa·s,4 %溶液为 175mPa·s,5 %溶液为 180mPa·s;4 %VES 70溶液的表现粘度随 pH值增大而增大 ,pH =1时不增粘 ,pH为 2～7时迅速增粘 ,pH为 9～ 11时增粘减慢。在 6 5℃、170s-1进行的 90min耐温剪切测试中 ,4 %VES 70溶液粘度降至 6 0mPa·s左右并保持稳定 ,这是VES压裂液的一个特点。在振荡频率为 6 .2 4rad/s时 ,随温度升高 (2 5～70℃ ) ,4 %VES 70压裂液的G′减少 ,G″增大 ,在 5 3℃时由G′ >G″变为G″ >G′ ,但G′值均 >2 .0Pa。 4 %VES 70压裂液以不同体积比与吉林原油混合 ,在 6 5℃破胶时间为 31.2～ 14 .1min ,破胶液粘度 5 .6～ 6 .1mPa·s ;与柴油等体积混合 ,6 5℃破胶时间 13.6min ,破胶液粘度 2 .7mPa·s ,表面张力 2 9.6mN/m ,界面张力 0 .33mN/m。在 6 5℃、3.5MPa下 4 %VES压裂液在低渗 (0 .0 80 7× 10 -3 μm2 )储层岩心中动态滤失系数为 7.5 2× 10 -4m/min0 .5,初滤失量为 2 .11× 10
Viscoelastic surfactant VES-70 based fracturing fluid (FF) is composed of a compounded surfactant, VES-70, and a clay stabilizer where VES-70 contains C_(16),C_(18) alkyl trimethyl ammonium salt and organic acid(s) and isopropyl alcohol. The performance properties of VES-70 micellar gelling solutions are investigated in laboratory. The apparent viscosity at 30℃ and 170 s^(-1) of VES-70 solutions increases with increasing VES-70 volume fraction(57, 175, and 180 mPa·s for 2%, 4%, and*'5% solutions, respectively) and that of 4% VES-70 solution increases with increasing pH value(no viscosification of the solution appears at pH=1, viscosification proceeds fast at pH*'2-7 and slower at pH*'9-11). In heat/shear resistance test at 65℃,170*'s^(-1)*'in 90 min, the viscosity of 4% VES-70 solution decreases to 60 mPa·s ca and keeps unchanged, demonstrating a distinguished rheologic behavior of VES FFs. With raising temperature from 25℃ to 70℃ at angular frequency 6.25 rad/s, value G′ of 4% VES-70 solution decreases and G″ - increases and at 53℃ conversion of G′>G″ to G″>G′ occurs but G′>2.0*'Pa is always true. The breakdown time is in range (31.2)-14.4 min and the viscosity of broken FF - in range 5.6-6.1 mPa·s for 4% VES-70 FF mixed with a crude oil of Jilin in volume ratio 2∶8-8∶2*'at 65℃; breakdown time 13.6*'min, viscosity of broken FF 2.7 mPa·s, its surface tension 29.6 mN/m and interfacial tension 0.33 mN/m are observed when 4% VES-70 FF is mixed with diesel oil in equal volume ratio at 65℃. In a low permeable(0.0807×10^(-3)*'μm^2)reservoir core at 65℃ under pressure 3.5 MPa with 4% VES-70 FF, the coefficient of dynamic filtrate loss is of 7.52×10^(-4)*'m/min^(0.5), the initial filtrate loss - 2.11×10^(-4)*'m^3/m^2, the percent damage to permeability - (35.2%), which is decreased to 3.84% after the core having been washed by kerosene. The low damage of VES-70 FF is evidenced by ESEM photos of the test core.
出处
《油田化学》
CAS
CSCD
北大核心
2004年第2期120-123,共4页
Oilfield Chemistry
基金
国家 973项目 (编号 2 0 0 1CB2 0 910 7)
关键词
表面活性剂
压裂液
VES-70
长链烷基季铵盐
有机酸
异丙醇
VES
cationic surfactant
long chain alkyl ammonium salt/organic (acid(s)/isopropyl) alcohol composition
micellar solutions
micellar gels
viscoelastic surfactant (VES) fracturing fluid
performance properties
