中高温VES压裂液用表面活性剂NTX-100

Surfactant NTX-100 for Middle-High Temperature Viscoelastic Surfactant Fracturing Fluid

由长链脂肪酸合成了多头季铵盐型表面活性剂NTX 100(有效物≥50%)。由4.0%NTX 100、0.3%pH调节剂、3.0%KCl和清水组成的压裂液体系,20℃、40℃、60℃下的粘度(170s-1)分别为146、134、97mPa·s,在室温放置1个月后粘度基本不变。粘温曲线表明,NTX 100体系压裂液的最佳pH值为6.0～6.5,在100℃下4.5%NTX 100、0.2%pH调节剂、2.1%KCl体系的粘度保持在50mPa·s。在振荡频率0.1HZ、温度20～90℃范围,随温度升高,上述4.5%NTX 100体系的G′值先略下降,高于45℃后大幅上升,高于约68℃后又持续下降;G″值则先基本稳定,高于60℃后上升;在90℃时G′和G″均大于20℃时的值。上述4.5%NTX 100体系与20%(以体积计)柴油混合后破胶,破胶液30℃粘度为14mPa·s,静置后分为三层,由上层油相体积计算,破乳率>70%,静置后的破胶液与等体积水混合后,粘度为4.2mPa·s。NTX 100耐温性良好,可用于110℃左右的中高温井压裂。图3表1参7。

A multi-head quarternary ammonium salt type surfactant, notated as NTX-100, with ≥50% active substances is prepared from long chain fatty acids. For viscoelastic surfactant (VES) fracturing fluid (FF) composed of 4.0% NTX-100, 0.3% pH regulator, and 3.0% KCl in fresh water, the apparent viscosity (AV) at 170 s^(-1) is of 146, 134, and 97 mPas at 20℃, 40℃, and 60℃, respectively, and maintains practically unchanged in one month of storage at ambient temperatures. The viscosity-temperature relationships show that the optimal pH value for FFs on this VES is in range 6.0—6.5 and the AV maintained at 100℃ is about 50 mPas for an experimental FF of 4.5% NTX-100+0.2% pH regulator+2.1% KCl. For the same FF at vibrating frequency 0.1 Hz and temperatures raised from 20 to 90℃, the G′ value slightly lowers down at 20—45℃, raises significantly at >45℃ and lowers down continuously at >68℃; the G″ value maintains practically unchanged at 20—60℃ and raises at higher temperatures; both the G′ and G″ values are higher at 90℃ than at 20℃. This experimental VES micellar gel breaks down when mixed with 20% (in volume) diesel oil; the broken gel has viscosity 14 mPas at 30℃ and separates into three phases at standing for long time with demulsifying rate being >70% as determined on the basis of volume of upper, oil, phase; the mixture of the phase-separated system and water in equal volume has viscosity 4.2 mPas. VES NTX-100 is temperature resistant and FFs on NTX-100 can be used in fracturing wells of middle-high temperature up to 110℃ ca.