岩石物性影响下切削齿破岩特征及动力学响应数值模拟研究

Numerical simulation study on the characteristics and dynamic response of PDC cutter breaking rock under the influence of rock physical properties

摘要:

随着我国对非常规地质能源勘探开发力度的持续加大，深层及复杂岩性地层的钻井作业日益频繁。在这一背景下，实现高效、经济、安全的钻井作业已成为行业关键课题，而钻探技术与装备的智能化、精准化提升则是其核心推动力。其中，切削齿作为钻头直接参与岩石破碎的核心单元，其与岩石之间的相互作用机制是影响钻头结构设计、钻进参数决策及整体钻进效率的关键因素。因此，本文聚焦PDC钻头切削齿的破岩过程，采用ABAQUS有限元软件，建立了二维PDC齿破岩过程数值模型，系统探究了岩石物理性质对破岩机理及切削齿动力学响应的影响。通过分别引入Drucker-Prager破坏准则与Cohesive单元模型，模拟了切削齿破岩过程中的岩石裂纹萌生、扩展及断裂行为。研究分析了在不同岩石物性、岩性条件下的切削力与振动加速度响应特征。结果表明，岩石抗压强度对切削力及振动响应影响最为显著，内摩擦角次之，弹性模量影响相对较小；针对岩石物性参数系统即不同岩性的平均切削力排序为花岗岩>砾岩>石灰岩>砂岩，且振动加速度与平均切削力呈正相关。该研究为基于钻头动态响应的岩石物理参数识别提供了理论依据，对非常规地质能源深部钻井的参数优化、地层岩性识别及智能钻井技术发展具有重要意义。

Abstract:

With the continuous intensification of the exploration and development of unconventional energy resources in our country， drilling operations in deep and complex lithologic strata are becoming increasingly frequent. Against this backdrop， achieving efficient， economical and safe drilling operations has become a key issue in the industry， and the intelligent and precise improvement of drilling technology and equipment is the core driving force. The PDC cutter， as the core unit of the drill bit that directly participates in rock breaking， and its interaction mechanism with the rock is a key factor affecting the structural design of the drill bit， the decision-making of drilling parameters， and the overall drilling efficiency. Therefore， this paper focuses on the rock-breaking process of PDC cutters， and uses ABAQUS finite element software to establish a two-dimensional numerical model of the rock-breaking process of the PDC cutter， systematically exploring the influence of rock physical properties on the rock-breaking mechanism and the dynamic response of the cutter. By introducing the Drucker-Prager failure criterion and the Cohesive element model， the rock crack initiation， propagation and fracture behavior during the rock-breaking process of the cutter were simulated. The study analyzed the response characteristics of cutting force and vibration acceleration under different rock physical properties and lithology conditions. The results show that the compressive strength of the rock has the most significant influence on the cutting force and vibration response， followed by the internal friction angle， and the elastic modulus has a relatively small influence. The average cutting force of different lithologies is ranked as granite > conglomerate > limestone > sandstone， and the vibration acceleration is positively correlated with the average cutting force. This research provides a theoretical basis for the identification of rock physical parameters based on the dynamic response of drill bits， with important implications for the parameter optimization of deep drilling for unconventional energy resources， the identification of formation lithology and the development of intelligent drilling technology.