热采井砾石充填防砂筛管外挤受力分析及应用

筛管外挤力研究分析是筛管砾石充填防砂热采井筛管强度校核和入井防砂管柱设计优化的基础。国内外对筛管外挤力的研究较少,尚缺乏相应的解析计算方法。温度膨胀效应和接触应力约束作用是热采防砂井筛管-砾石层界面变形的制约因素。文中首先建立了温度效应造成的砾石层-地层系统内径变化计算模型和筛管外径变形模型,然后借助Lame方程求解得到筛管-砾石层界面位移与外挤力之间的关系曲线。综合考虑温度膨胀效应和接触应力约束作用,提出了热采井筛管外挤力计算的筛管-砾石层-地层耦合模型,并采用图版法求解筛管外挤力。实际计算表明,当井底温度达到350℃时（井底升温300℃）,温度效应造成筛管-砾石层界面位移为1.855 mm,该位移条件下的筛管外挤力为17.78 MPa。该成果可为热采防砂井筛管强度校核及砾石充填施工提供依据。

Analysis and application of screen external squeezing pressure in thermal gravel packing wells

Screen external squeezing pressure calculation and analyses are essential for screen strength verification and optimization design as well for wells that is gravel packed,especially for heavy oil wells located in unconsolidated formation.The problem hasn ′t been solved since the lack of relevant analytical model.Thermal expansion and contact stress are constraints among screen and gravel contact surface and a simplified model for internal radius of the gravel and external radius is proposed in this paper.Then,Lame equation is introduced in order to figure out the relationship between screen external squeezing pressure and contact surface displacement.Coupling model and corresponding chart method are raised,which is convenient for screen external squeezing pressure calculation.It is proved by numerical simulation that screen-gravel surface movement is about 1.855 mm with relevant 17.78 MPa screen external squeezing pressure under 350 ℃ bottom hole temperature and 300 ℃ temperature rising.The research findings can provide a basis for screen strength verification and gravel operations under thermal conditions.