高效驱油压裂液的开发与应用

针对长庆油田现用瓜胶压裂液摩阻高、破胶残渣多、回收处理难度大的问题，将超分子化学、胶体化学与油田化学相结合，研发出一种可替代瓜胶压裂液的高效驱油清洁压裂液体系，该压裂液由1.5% XYZC-6稠化剂、0.15% XYTJ-3调节剂组成。XYZC-6是一种以近肽链结构的黏弹性表面活性剂与多组分有机溶剂复合而成的材料，是一种可实时连续混配并能重复使用的增稠剂。XYTJ-3与返排液中的各项离子可形成溶于水的络合物，降低矿化度对压裂液的性能影响。实验表明，该压裂液耐温90℃，抗盐可达100 000 mg/L，具有良好的携砂、减阻性能，并且压裂液破胶彻底，破胶液残渣含量为2 mg/L，破胶液的界面张力可达0.01~0.001 mN/m。高效驱油压裂液在长庆油田靖安区块得以成功应用，产后单井产量是相邻井产量的2倍，返排液经分离沉降等简单处理后即可再配压裂液，末端返排液经处理可用于驱油，变废为宝，实现压裂液"零排放、零污染"，大幅度降低了压裂液的环境污染，为压裂液"不落地"技术提供了保障。 

Development and Application of a High Efficiency Oil Displacing Fracturing Fluid

A high efficiency oil displacing fracturing fluid has been developed to replace guar gum fracturing fluid in dealing with problems associated with fracturing fluids, such as high friction, too many residues after gel breaking and difficulties in fracturing fluid recovery. This fracturing fluid was formulated with 1.5% XYZC-6 and 0.15% XYTJ-3. XYZC-6 is a thickening agent made with a viscoelastic surfactant having peptide chain structure and a multi-component solvent; it can be mixed continuously in fracturing fluid in field operations and can be re-used. XYTJ-3, a modifier, can react with ions in the flowback fluid to form water-soluble complexes, thereby minimizing the effects of salinity on the performance of fracturing fluid. Experimental results showed that the fracturing fluid functioned normally at 90℃, was resistant to salt contamination to 100,000 mg/L, and performed very well in sand carrying and in fraction reducing. Gel breaking of the fracturing fluid can be done efficiently; the residue content of the gel-broken fluid was as low as 2 mg/L, and the interfacial tension of the gel-broken fluid was 10-2-10-3 mN/m. The fracturing fluid has been used successfully in the block Jing'an in Changqing oilfield. Wells fractured with this high efficiency oil displacing fracturing fluid have got oil production rates that are 2 times of the production rates of offset wells. The flowback fluid, after separation and sedimentation, can be re-used in formulating new fracturing fluid. The final flowback fluid can be used in oil displacement, helping realize the objectives of "zero discharge and zero pollution", greatly reducing the environment pollution risks associated with well fracturing operations. The use of this fracturing fluid has provided technical support for "not-falling-to-the-ground" of fracturing fluids.