新型单元式固井地锚的结构设计及仿真研究

Structural Design and Simulation Study of a New Unit-type Cementing Ground Anchor

针对稠油热采井进行预应力固井时，套管串下端锚固困难和锚固力不能满足设计要求的问题，设计了一种新型单元式、可复位预应力固井地锚。该地锚可根据不同的地层情况采用多个单元组合，并可根据井径大小不同安装不同长度的锚爪。利用ANSYS／LS—DYNA对锚爪吃入不同井径井壁的过程进行了动态模拟分析，得出了不同初始吃入角度时，地层反力的变化规律，指出最有利于锚爪吃入井壁的吃入角度为30°～40°，这为设计中锚爪几何参数的确定及作业时选用爪型提供了依据。最后通过台架试验验证了锚爪-锚爪销系统的强度。

There is an anchoring difficuhy with the lower end of casing string and the anchoring force cannot satisfy the requirement of design in prestressing cementation in heavy oil thermal recovery wells. Therefore, the structural scheme for a new kind of unit-type, resettable prestressing cementing ground anchor was designed. The scheme can adopt several unit combinations according to different formation conditions and it can install the flukes of different lengths according to different well diameters. The ANSYS/LS-DYNA was used to conduct a dynamic simulation analysis of the penetration process of the fluke into the well walls of different well diameters. The variation law of formation reaction was derived in different initial penetration angles. It is pointed out that the angle which is most favorable to the penetration of the fluke into well wall is between 30°and 40°. This provides the basis for the determination of the geometric parameters in designing the fluke and the choice of fluke type in operation. Finally, the strength of the fluke and fluke pinhole system was verified through bench test.