高压脉冲注入作用下套管-水泥环-地层系统应力分析

Stress Analysis of Casing-cement-formation System Under High Pressure Pulse Injection

为了进一步提高油气增产,人们提出了周期脉冲注水技术,通过多重循环的高压脉冲注水,可以有效改变地层压力场,提升油藏产油潜能。但是周期性的高压脉冲载荷也为结构安全运行带来了极大的挑战。主要分析了周期脉冲压力作用下套管-水泥-地层系统水泥层应力状态。首先使用Ansys仿真软件对该组合体进行建模,然后考虑不同注水压力和脉冲周期,计算了套管和水泥层的瞬态应力变化。数值结果表明:随着注水频率的增大,套管和水泥环的应力有所下降,从0.05 Hz升到0.2 Hz时,套管的应力下降了约10%,水泥环的应力下降了约14.6%。套管和水泥环的应力与注水压力基本成正比。

Periodic pulse water injection technology has been proposed to further increase oil and gas production Through multiple cycles of high-pressure pulse water injection,the formation pressure field can be effectively changed and the oil production potential of the reservoir can be improved.However,periodic highvoltage pulse loads also bring great challenges to the safe operation of structures.Mainly analyzes the stress state of the cement layer of the casing-cement-formation system under the action of periodic pulse pressure.Firstly,Ansys simulation software is used to model the assembly.Then,considering different water injection pressures and pulse periods,the casing is calculated Transient stress changes in pipes and cement layers.The numerical results show that with the increase of water injection frequency,the stress of casing and cement sheath decreases.When the water injection frequency increases from 0.05Hz to 0.2Hz,the stress of casing decreases about 10%,and that of cement sheath decreases about 14.6%.The stress of casing and cement sheath is basically proportional to the water injection pressure.