CSAa黏弹性表面活性剂压裂液的研制

A Study on Viscoelastic Surfactant Fracturing Fluid on Long Chain Alkyl Ammonium Salt CSAa

用化学试剂长链烷基季铵盐CSAa制备了两种VES压裂液并研究了相关性能,其组成(CSAa/水杨酸钠/氯化钾/正丁醇,以g/dL为单位)如下:1.0/0.3/1.0/0.2;2.0/0.6/0.5/0.1。在耐温性测定中,1.0 g/dL CSAa压裂液的黏度由30℃时的75.0 mPa.s降至50℃时的37.5 mPa.s;2.0 g/dL CSAa压裂液的黏度由40℃时的225 mPa.s逐渐降至55℃时的110 mPa.s,再降至60℃时的65.0 mPa.s。在170 1/s剪切2 h后,剪切温度为42℃时1.0 g/dLCSAa压裂液的黏度下降26%,剪切温度为53℃时2.0 g/dL CSAa压裂液黏度下降9%。陶粒沉降速度测定结果表明,40℃、42℃时的1.0 g/dL CSAa压裂液(黏度分别为60和54 mPa.s)和50℃、53℃时的2.0 g/dL CSAa压裂液(黏度分别为180和145 mPa.s)携砂性能良好,而45℃、50℃时的1.0 g/dL CSAa压裂液和55℃、60℃时的2.0 g/dL CSAa压裂液,携砂性能则较差或很差。认为VES压裂液的携砂性能来源于棒状胶束网络,并不全由压裂液黏度决定。还考察了VES压裂液的破胶性能。图1表2参5。

Two VES fracturing fluids （FFs） on a chemical pure long chain alkyl ammonium salt, CSAa, are prepared and evaluated for their performance properties. Their composition in g of CSAa ＋ NaSal ＋ KCl ＋ n-butanol per 100 mL water is 1.0 ＋ 0.3 ＋ 1.0 ＋ 0.2 and 2.0 ＋ 0.6 ＋ 0.5 ＋ 0.1 and these are notated as CSAa-FF-1.0 and CSAa-FF-2.0. In heat resistance tests at 170 1/s, the viscosity of CSAa-FF-1.0 decreases from 75.0 mPa· s at 30℃ to 37.5 mPa·s at 50℃ and of CSAa-FF-2.0-from 225 mPa·s at 40℃ to 110 mPa·s at 55℃ and to 65.0 mPa·s at 60℃. The viscosity of CSAa-FF-1.0 is reduced by 26% in 2 hrs sheafing at 170 1/s and 42℃ and of CSAa-FF-2.0-by 9% in 2 hrs sheafing at 170 1/s and 53℃. The measurements of proppant sedimendation velocity show that excellent proppant carrying capability （PCC） is observed for CSAa-FF-1.0 at 40℃ and 42℃ with viscosity of 60 and 54 mPa＇s and for CSAa-FF-2.0 at 50℃ and 53℃ with viscosity of 180 and 145 mPa·s, respectivdy, meanwhile worse and had PCC- for CSAa-FF-1.0 at 45℃ and 50℃ and for CSAa-FF-2.0 at 55℃ and 60℃. It is considered that for VES FFs high PCC originates from their micellar network rather than their increased viscosity. The breakdown of CSAa-FF-1.0 and -2.0 is also investigated.