安全高效钻探用梯度结构金刚石复合片制备技术研究

Research on the preparation technology of gradient structure diamond composite disc for safe and efficient drilling

摘要:

在油气钻井、深部地层钻探中，聚晶金刚石钻头有着广泛的应用。聚晶金刚石复合片（PDC）由聚晶金刚石层与硬质合金基体所组成。由于聚晶金刚石层与硬质合金基体的热膨胀系数等性质差异，PDC在烧结冷却后内部会存在巨大的残余应力。为降低PDC内部的残余应力，本文提出了一种梯度结构金刚石复合片的制备技术。通过以熔融沉积成型加烧结的工艺方法，确定了梯度结构金刚石复合片的制备技术路线；对制备出的梯度结构金刚石复合片的微观形貌及残余应力的分布情况特征等进行分析；进行室内钻进试验验证了梯度结构金刚石复合片的钻进性能。结果表明，熔丝制造工艺制备的梯度结构金刚石复合片在聚晶金刚石层和梯度层界面处存在1.4 GPa的压应力，显著提高了层间结合能力，相比常规复合片钻进效率提升约36%且使用寿命更长。

Abstract:

Polycrystalline diamond bits have the widest application in oil and gas drilling and deep formation drilling. Polycrystalline diamond compact （PDC） consists of a polycrystalline diamond layer and a cemented carbide substrate. Due to the difference in the coefficient of thermal expansion between the polycrystalline diamond layer and the tungsten carbide matrix， there is a huge residual stress inside the PDC after sintering and cooling. To solve the problem of reducing the residual stresses inside the PDC， this paper reports a preparation technology for gradient structure diamond compact. Through the process of fused deposition modelling and sintering （FDMS）， the technical route for the preparation of gradient structure diamond compact was determined； the micro-morphological features of the prepared gradient structure diamond compact and the distribution of the residual stresses were analysed； and the indoor drilling tests were carried out to verify the drilling performance of the gradient structure diamond compact. The results show that the gradient structure diamond compact prepared by the FDMS has a compressive stress of 1.4GPa at the interface between the polycrystalline diamond layer and the gradient layer， which significantly improves the interlayer bonding ability and effectively reduces the internal residual stress， and improves the drilling efficiency by about 36% and the service life is longer compared with that of the conventional compact.