一种新型清洁压裂液体系的研究及应用

Research and application of a new clean fracturing fluid system

关键词:  新型清洁压裂液  缔合  抗高温性  抗剪切性 

Key words:  a new type of clean fracturing fluid  association  high-temperature resistance  shearing resistance

摘要:

利用分子间的静电作用以及疏水基团的缔合作用,研制出一种新型清洁压裂液,从耐高温性、抗剪切性、黏弹性、流变参数、滤失性、破胶性、抗盐性以及对地层伤害性等方面对该压裂液体系进行评价,发现该新型压裂液分别在130 ℃和160 ℃、170 s-1下剪切1 h后,黏度仍保持在40 mPa·s以上,残渣量为0,岩心伤害率为21.72%,沉砂速率为1.96×10-4 m/min,滤失系数C₃=7.622×10-4 m/min,且压裂液性质不受水中盐浓度的影响。此外,与传统胍胶压裂液进行对比发现,该新型压裂液在抗高温性与抗剪切性方面与胍胶压裂液相差甚微,而在伤害性、破胶性等方面则远远优于胍胶压裂液。该压裂液在高速剪切下黏度下降,剪切速率降低时,黏度随之恢复,这一特点可大大降低施工摩阻。该新型压裂液具有的上述特点,使之可望取代胍胶压裂液,成为可满足油田压裂施工的压裂液体系。在G34-0X井盒8段的压裂施工中应用效果显著,可满足现场施工需求。 

Abstract:

A new type of clean fracturing fluid was developed by using the electrostatic interactions between molecules and the association of hydrophobic groups. It was evaluated from the facts of high-temperature resistance, shearing resistance, viscoelastic, rheological parameter, loss property, gel break property, salt resistance, and formation damage. The result showed that the viscosity of this new fracturing fluid was over 40 mPa·s by shearing for 1 h at 130 ℃, 160 ℃,170 s-1 respectively, the amount of residue was 0, core damage rate was 21.72%, settling velocity was 1.96×10-4 m/min, filtration coefficient C₃ was 7.622×10-4 m/min and the fracturing fluid property was not affected by the salt concentration in water. Besides, compared with guar gum fracturing fluid, this new type of fracturing fluid had the same performance in high-temperature resistance and shearing resistance, and better in core damage rate and gel break property. In addition, when this new type of fracturing fluid was in a faster shearing rate, its viscosity would decrease, and when the shearing rate became slow, viscosity would recover. This character could greatly reduce the friction when the fluid was in tube. Based on above characteristics of this new fracturing fluid, it could completely replace guar gum fracturing fluid. The fracturing fluid acted very well in the test of G34-0X well, and could meet the requirements of field operation perfectly.