特深井钻杆接头耐磨减摩双向防护机制研究

Research on bidirectional protection mechanism for wear and friction reduction of drill pipe joints in extra-deep wells

摘要:

针对深井、超深井、特深井钻井过程中钻杆接头耐磨带-套管摩擦副的严重磨损问题，建立了钻柱-套管耐磨减摩的双向防护模型，提出了金刚石复合材料耐磨带与套管的双向防护机制，并开展了金刚石复合材料耐磨带摩擦学性能实验验证。该研究阐释了金刚石复合材料耐磨带耐磨减摩的机理，并通过构建包含岩层轴向反力和接触载荷的钻柱-套管的力学模型，采用自主研发的摩擦磨损试验机进行实验。研究不同工况下钻杆接头的磨损量及磨损形貌特征，结合拉曼光谱揭示了表面摩擦化学反应机制。结果表明：金刚石复合材料耐磨带通过硬质相支撑和自润滑协同作用，可使摩擦系数显著降低，形成的梯度复合保护层和石墨化转移膜能有效实现钻杆接头与套管表面的双向防护。研究成果为深井钻杆接头耐磨带结构优化提供了理论支撑与实验依据。

Abstract:

Aiming at the serious wear problem of the wear band and casing friction pair of drill pipe joint during drilling in deep， ultra-deep and extra-deep wells， the bidirectional protection model of drill string and casing wear and friction reduction was established in this study. The bidirectional protection mechanism of diamond composite wear band and casing was proposed， and the tribological properties of diamond composite wear band materials were verified by experiments. This study systematically explained the wear resistance and friction reduction bidirectional protection mechanism of diamond composite wear band material. By constructing a drillstring-casing mechanical model containing rock axial reaction and contact load， the friction and wear testing machine independently developed was used to conduct experiments， and the friction coefficient， wear amount and wear morphology characteristics were compared and analyzed under different working conditions. Combined with Raman spectroscopy， the mechanism of surface tribochemical reaction was revealed. The results show that through the synergistic effect of the hard phase support and self-lubrication， the friction coefficient of the diamond composite wear zone can be significantly reduced. The formed gradient composite protective layer and graphite transfer film can effectively achieve two-way protection between the drill pipe joint and the casing surface. The research results provide theoretical support and experimental basis for the structural optimization of wear band of drill pipe joints in deep wells.