稠油热采井注汽及油层出砂对套管的影响

对胜利油田单二区块稠油热采井注汽及油层出砂进行了有限元数值模拟研究,得出如下结论:(1)油层注汽引起岩层温度升高,套管应力增加,易造成套管轴线偏离,发生错断;(2)热采井出砂严重时,出砂区域地层软化,地层骨架失去承载能力,出砂区域内套管轴向应力为压应力,当超过极限应力时,易发生套管弯曲变形、错断和缩径;(3)随着出砂量的增大,套管射孔孔眼应力集中系数增大,当孔边应力达到套管材料的屈服极限时,会导致孔眼塑性破坏。

Influence of steam injection and sand production on casing in heavy oil thermal recovery wells

A finite element numerical simulation investigation is made in the steam injection and sand production of the thermal recovery wells in Dan 2 block in Shengli Oil Field. Conclusions are drawn as follows: (1) steam injection causes rise of formation temperature and increase of casing stress, resulting in casing breakage; (2) While serious sand problem occurs, the formation in the sand entry area is softened, therefore the axial stress on the casing is actually a press stress, and when this stress becomes higher than the stress limit, the deformation, bending and shrinking of the casing occur; (3)With the increase of the sand production rate, the stress concentration coefficient at the perforating tunnel increases, and when the stress at the perforation edges reaches the yielding limit of the casing material, plastic damage of the perforation may occur.