BCG-1深井加重清洁压裂液体系

对于埋藏深、低渗透和温度高的储层进行压裂改造施工时,抗高温硼交联改性瓜胶压裂液体系存在摩阻高、残渣不能消除的问题。在实验室中合成了一种具有一定水解度的以丙烯酰胺和离子功能单体为主链的聚合物压裂液稠化剂,通过对添加剂进行优选,形成了一种BCG-1加重清洁压裂液体系。室内实验结果表明:BCG-1加重压裂液体系具有良好的耐温耐剪切性,在160℃、170 s-1条件下剪切120 min,压裂液黏度保持在57 mPa·s以上,且该压裂液配方实验重复性好。用自行设计并研制的多功能流动回路摩阻测试仪对BCG-1加重压裂液进行摩阻测试,实验采用8 mm测试管径,测试数据显示,体系增效剂ZJFA-1具有很好的降低BCG-1压裂液体系摩阻的特性;NaNO₃加重剂对该体系摩阻性能基本无影响;体系破胶性能好,破胶液黏度小于21 mPa·s,残渣含量小于5 mg/L,具备清洁压裂液的特性。 

Weighted Clean Fracturing Fluid for Deep Well Stimulation

High temperature borate cross-linked guar gum fracturing fluids have long been used in fracturing deep,low permeability and high temperature reservoirs.High friction and the difficult-to remove residues of the fracturing fluids are two problems that have to be faced with in the fracturing jobs.A thickening agent,with acryl amide and ionic functioning groups as the molecular backbone,is developed for use in fracturing fluid.It has a certain degree of hydrolysis.A weighted clean fracturing fluid,BCG-1,has been formulated using this thickening agent and other additives carefully selected.In laboratory experiments,BCG-1 demonstrated good high temperature and shear resistance performance.The viscosity of BCG-1 maintained at 57 mPa·s or higherafter shearing 120 min at 160℃ and 170 s-1,and good repeatability of the experiments can be obtained.Friction test on 8 mm flow tubes reveals that ZJFA-1,an extender for the fracturing fluid,greatly reduces the friction of BCG-1.NaNO3 as a weighting agent has almost no effect on the friction of BCG-1.BCG-1,after gel-breaking,has a viscosity less than 21 mPa·s,and residue content less than 5 mg/L,characteristic of clean fracturing fluid.