一界面存在微间隙的热采井井筒热应力分析

Borehole thermal stress analysis of thermal recovery well with micro-annulus in its first interface

针对二界面固结良好,一界面存在微间隙的固井质量问题,建立了三岩层剖面的有限元模型,研究了微间隙对井筒温度场和应力场的影响。分析结果表明,微间隙改变了井筒径向温度分布的连续性;相对于所研究的整个岩层段,微间隙段井筒温度为低值点。在蒸汽吞吐过程,由于微间隙的影响,套管在温度场作用下部分约束得到释放,使得套管上产生的等效热应力较低。同时,微间隙段套管和水泥会产生较大的径向位移,给工程测井带来困难,可能使固井解释评价出现偏差。

Aimed at the cement job quality problem that the second interface is strong bonding and micro-annulus is lied in the first interface, three rock lays FEA model is established. The influence of micro-annulus on borehole temperature field and stress field is studied. The result shows that micro-annulus changes the consistence of radial temperature field and borehole temperature in micro-annulus stratum is lower than other stratum's. During steam stimulation, because of micro-annulus' influence, partial restriction of casing is released and the equivalent stress on casing is lowered. At the same time, radial displacement of casing and cement is changed. It is difficult for engineering log and it may cause the primary cement evaluation appear bias.