不关井分体式排水采气柱塞结构优化研究

Study on Structural Optimization of Two-piece Gas Recovery Plunger without Well Shut-in

针对分体式柱塞存在的气体窜流、液体回落及下井困难等问题,以典型分体式柱塞为基础,建立了柱塞在油管内运行的流场数值计算模型,以阻力系数为评价依据,对内外壁结构开展了基于数值模拟的结构优化。数值计算结果表明:圆弧形柱塞外壁环槽结构具有更好的密封性能,并确定其槽宽16mm、槽深7mm为最优结构;文丘里结构作为分体式柱塞内孔结构,可显著提升下井速度,采用正交实验法确定最优参数组合为收缩角50°,喉管直径32mm,扩散角16°,相比通孔型柱塞下井速度提升了44%。利用室内实验装置对优化后柱塞结构运行、排液进行了实验研究,验证了模拟的可靠性。

In view of the gas cross-flow,fluid drop and the difficulty in descent which troubles two-piece plungers,the flow field's numerical calculation model of the plunger running in the tubing was established.Based on the evaluation of the resistance coefficient and though numerical simulation,the two-piece plunger's internal and external wall structure were optimized.The numerical results showed that,the circular arc groove structure for the plunger's external wall has better sealing performance and the groove width of 16mm and depth of 7mm are optimal.Venturi structure,as the two-piece inner bore structure can significantly improve its descent velocity.The optimal combination of parameters determined by orthogonal experiment is 50°angle of throat,32mm throat diameter and 16°spread angle,this can increase the descent velocity by 44% compared with through-hole plunger.The laboratory experiment on both operation and drainage of the optimized plunger structure proved the reliability of the simulation.