油田常温集输环境下聚乙烯适用性研究

Compatibility of Polyethylene in Oilfield Gathering Medium at Room Temperature

针对长庆油田试用的钢丝增强复合管聚乙烯内衬,采用宏观与微观相结合的手段,通过反应釜挂片实验分析温度25℃、压力0.1~6.0 MPa条件下聚乙烯在采出水与采出油两种集输介质中的渗透行为。实验发现,采出水与采出油均能渗透进入聚乙烯内部使其溶胀,溶胀引起的增重率最大为1.96%;介质渗入后,聚乙烯微观结构更致密,未发现银纹及裂纹;采出油的渗透率大于采出水,而采出水的渗透深度大于采出油;渗透深度随压力升高呈幂指数增加;光氧老化作用对试样屈服强度、拉伸强度、断裂伸长率、冲击强度的影响高于介质渗透作用。结果表明,常温条件下,聚乙烯在采出水、采出油环境中的适用性良好,可以推广使用。

Aiming at the polyethylene liner of steel wire reinforced composite pipe applied in Changqing Oilfield,the penetration behavior of polyethylene in the gathering mediums of produced water and petroleum from the wellhead was studied by hanging piece experiments with temperature of 25 ℃ and pressure of 0.1~6.0 MPa by macro and micro methods.It was found that produced water and produced petroleum can permeate into polyethylene to make it swell.The maximum weight gain rate caused by swelling was 1.96%.The microstructure of polyethylene became denser and there was not silver grain and crack.The permeability of produced petroleum was larger than produced water,while the penetration depth of produced water was greater than produced oil.The penetration depth increased exponentially with the increase of pressure.The influence of photooxidative aging on the yield strength,tensile strength,elongation at break and impact strength of samples were significantly higher than the effect of medium permeability.The results show that the polyethylene liner has a good compatibility in medium of produced water and petroleum and it could be widely applied.