基于试验和数值仿真的封隔器卡瓦结构优化

Structure Optimum of Packer Slips Based on Test and Numerical Simulation

永久式封隔器是页岩气开采过程中分段压裂的必备工具,其卡瓦结构直接影响封隔器的坐封性能。针对Y440型封隔器进行坐封、验封试验,工具在验封过程中存在下移情况,井下冲击与振动可能使工具下移加剧甚至滑脱、漏封。基于非线性显式动态分析方法,建立有限元模型,综合评估不同卡瓦牙型参数下卡瓦、套管的应力值、等效塑性应变、卡瓦滑移量。分析得出牙倾角20°、牙顶角75°、牙齿宽度8 mm、内锥角15°为相对最优的卡瓦结构。该文的研究工作为封隔器卡瓦的优化设计提供了科学依据。

The permanent packer is an essential tool for segment fracturing during shale gas exploitation. The structure of the slips directly affects its setting ability. For Y440 type packer, setting and sealing tests were carried out, and the results show that the packer exists slip during sealing operation, which may exacerbates slip and even slip off under the condition of shock and vibration in a wellbore. Finite element models were established based on nonlinear explicit dynamic analysis method. According to the comprehensive evaluation on the stress value, plastic deformation and the slippage of slips with the different tooth types, the results indicate that when the teeth dip angle is 20 degrees, vertex angle is 75 degrees, teeth width is 8mm and inner cone angle is 15 degrees is the relative optimal structure. A scientific basis for the design of packer slips was provided.