CO2泡沫压裂液的研究及现场应用

在水力压裂过程中，由于向地层中注入大量的压裂液，对地层造成了一定程度的伤害，特别是低渗透油藏压裂液对地层的伤害更加严重，从而影响了增油效果。由于CO2泡沫压裂液具有滤失量低、返排能力强、与地层流体配伍性良好等优点，采用CO2泡沫压裂技术，可减小压裂液对地层的伤害。经过对CO2泡沫压裂液的各种添加剂进行优选与评价，确定了适合低渗油藏使用的CO2泡沫压裂液体系，并对其综合性能进行了评价。结果表明，CO2泡沫压裂液体系具有泡沫质量高、稳定性好、半衰期长、粘弹性大的特点，并有良好的耐温耐剪切性能和流变性能，破胶彻底，界面张力低，对储层伤害小，可以满足低渗、低压油气藏压裂施工的需要。CO2泡沫压裂液在吉林油田和大庆油田的低渗透油碱中进行应用．取得了良好的效果。

Study on Foam Fracturing Fluid and Its Field Application

Fracturing fluid injected into formations may cause formation damage in somewhat degree and e ven worse for low permeability and low pressure zones. Formation damage can be minored by using CO2 foam fracturing fluid as it has low filtration, high flowback and good compatibility with formation fluids. The system and formulation of CO2 foam fracturing fluid have been determined and its properties have been evaluated after the comprehensive work on optimization and evaluation on different chemical additives a vailable for composition of this fluid. The study showed that CO2 foam fracturing fluid possesses the advantages of high foam quality, good stability, longer half-life period, strong viscoelasticity, excellent resistance to high temperature and shearing, satisfied fluidity, easily reached degradation, low interface tension and lowered formation damage therefore it adapts very well to the requirements of fracturing operations in low permeability low pressure formations. The excellent results were achieved in fracturing operations in low permeability formations in Jilin Oilfield and Daqing Oilfield.