O/W型交联乳化压裂液配方研究

Formulation study of oil-in-water crosslinked emulsion fracturing fluids

研制了一种交联O/W型乳化体系用作水力压裂的压裂液。它是通过采用复合乳化剂,应用D相乳化法,将油相以体积比为50∶50的比例分散于交联的HPG溶液相中得到的一种多相分散体系。该体系在80 ℃、170s-1下剪切,粘度可达到446.9 mPa·s,剪切2 h后粘度仍大于100 mPa·s;破胶后粘度降为2 mPa·s,压裂残渣含量仅为166 mg/L,能大大减少压裂液在裂缝中的滞留,有效降低对地层渗透率的伤害。该体系较其它压裂液体系具有很好的滤失控制、优良的破胶返排能力,对支撑剂有很好的悬浮稳定作用,适宜中低渗透率地层的压裂施工。通过对影响体系性能的各因素及交互作用进行研究,确立了地层温度不大于100 ℃的交联乳化压裂液配方。

A crosslinked oil-in-water emulsion system has been developed as fracturing fluids for hydraulic fracturing treatment in lab. It is a dispersion system of two phases, which applied a good multi-functional emulsion agent into crosslinked HPG solution, using the emulsion technique of D phase (kerosene or derv). The viscosity is 446.9 mPa·s at 170 s -1 /80 ℃,and after 2 hours of continual shearing, the viscosity stays at above 100 mPa·s; Once the system is broken, the viscosity will drop to 2 mPa·s and the residue content of fracturing fluid is only 166 mg/L. These capabilities are beneficial to reduce the residue of fracturing fluids and eliminate damage to reservoir. Compared with other fracturing fluids, the system has better fluid loss control and effective flow back, and stronger proppant suspension and transportation, qualifying it suitable for fracturing job in normal or low permeability oil reservoir. Based on experiments of all factors affecting the system capability and their interplay, fracturing fluid formulations were established for wells of no more than 100 ℃.