Fabrication and Performance of Gemini Oleamidopropyl Hydroxy Sulfobetaine (GOHSB) Used as a Viscoelastic Fracturing Fluid

Gemini oleamidopropyl hydroxy sulfobetaine (GOHSB) was prepared and characterized. The CMC of GOHSB was 7.19 × 10 –5 and 8.74 × 10 –5 mol/L, and the surface tension of GOHSB and gel breaking liquid was 31.7 and 48.9 mN/m, respectively. The viscosity of 2 wt % at pH 4 was 71.5 mPa s at the shear rate of 170 s –1 and the settling rate of proppant was 0.0047 mm/s. With the addition of 15000 mg/L of NaCl and CaCl 2 , GOHSB viscosity (2 wt %) was 26.94 and 18.51 mPa s at the shear rate of 170 s –1 . τ was called relaxation time. At 1 wt %, the τ was 0.019 s, while at 2 wt %, τ reduced to 0.013 s. GOHSB solution with 1 wt % showed elastic characteristics.