特深井超高压钻井泵十字头力学性能有限元分析

Finite element analysis of crosshead mechanical performance in ultra-high pressure drilling pump for ultra-deep wells

摘要:

针对15000 m特深井钻探对80 MPa超高压钻井泵的迫切需求，以及现有数字孪生体缺乏极端工况力学数据的瓶颈，系统开展了超高压钻井泵关键部件十字头的力学性能分析。首先，基于水力学理论计算了不同缸径（110~180 mm）下的额定泵压与排量，建立十字头运动学与受力模型以明确其载荷边界；继而基于Hertz接触理论，利用COMSOL软件对不同缸径?泵压组合工况进行有限元静力学仿真。结果表明：十字头最大应力与缸径及泵压呈正相关，且缸径变化对应力的影响显著大于泵压；应力危险点位于销孔外边缘与耳板过渡圆角处。在额定泵压和最大排量工况下最大应力分别为133.3、142.8 MPa，均远低于材料屈服强度860 MPa。研究量化了不同缸径-泵压耦合工况的应力响应曲面，填补了特深井超高压泵动力端极端工况力学数据空白，为现场缸套更换策略及十字头疲劳寿命预测提供了理论依据。

Abstract:

To address the urgent demand for an 80 MPa ultra-high-pressure drilling pump in 15000 m ultra-deep well drilling， and to overcome the bottleneck that existing digital twins lack mechanical data under extreme operating conditions， a systematic mechanical performance analysis was conducted on the crosshead， a key component of the ultra-high-pressure drilling pump. First， based on hydraulics theory， the rated pump pressures and displacements under different liner diameters （110~180 mm） were calculated， and a kinematic and force model of the crosshead was established to define its load boundary conditions. Subsequently， based on the Hertz contact theory， finite-element static simulations were performed using COMSOL software under various combinations of liner diameter and pump pressure. The results indicate that the maximum stress on the crosshead is positively correlated with both liner diameter and pump pressure， and the effect of liner diameter variation on stress is significantly greater than that of pump pressure. The stress concentration zone is located at the transition fillet between the outer edge of the pin hole and the lug body. Under the rated-pressure and maximum-displacement conditions， the maximum stresses are 133.3 MPa and 142.8 MPa， respectively， both far below the material''s yield strength of 860 MPa. This study quantifies the stress-response surface under coupled liner-diameter-pump-pressure operating conditions， fills the gap in mechanical data for the power end of ultra-high-pressure pumps for ultra-deep wells under extreme conditions， and provides a theoretical basis for on-site cylinder liner replacement strategies and fatigue-life prediction of crossheads.