深孔高温硬岩中涡轮钻进粘滑振动及其抑制机理研究

A turbodrill is an indispensable downhole motor for drilling under high temperature (≥250℃) in deep borehole. Due to its soft mechanical properties, the phenomenon of stick/slip vibration of the bit is likely to occur in hard rock formation, which probably can cause the turbodrill stall and even accidents. On the basis of the researching the drilling stick/slip vibration and anti-stall damping mechanism, a turbodrill drilling and coring technology are put forward. Firstly, by using gray box theory, a transfer function model has been developed, representing the relationship between the hydraulic characteristics and mechanical properties. Secondly, on the basis of nonlinear contact theory and tribological mechanism, the interaction mechanism was explored. In addition to this, a stick/slip vibration model of the turbodrill-bit-rock has been built based on nonlinear contact theory, tribological mechanism and vibration theory. Thirdly, a whole closed loop drilling model has been established on the basis of the anti-stall damping model, turbodrill transfer function model and the stick/slip vibration model, by using which, the structural parameters of drilling tools, drilling parameters and damping parameters are finally optimized under optimal drilling speed. At last, an effective drilling method and coring technology that can be used in typical hard rock formations have been developed out.

涡轮钻具是当前高温高压孔下（>250℃）可用的唯一动力钻具，但由于其固有的软机械特性，在深孔硬岩地层中，钻头极易出现粘滑振动，导致涡轮钻具制动失速、钻进效率低、钻头和钻具损坏，甚至诱发孔内事故等问题。课题在开展涡轮钻进粘滑振动和减振机理研究的基础上，提出涡轮钻进抗粘滑振动、提高钻进速度、延长钻头和钻具使用寿命高效钻进技术。首先，运用“灰箱”建模理论，建立涡轮钻具+孕镶金刚石钻头钻进传递函数模型；再利用摩擦学理论、非线性理论和金刚石钻进原理，研究孕镶金刚石钻头与典型硬岩相互作用机理，利用振动理论建立涡轮钻具水力部件-钻头（含取心筒）-岩石之间粘滑振动模型；在涡轮实钻实验基础上建立涡轮钻进抗粘滑和闭环钻井模型；以钻进速度和抗粘滑减振效果为优化目标，利用该模型为优化钻具结构参数、优化钻进工艺参数提供理论依据，进而提出适合深孔硬岩地层的涡轮钻进与取心工艺方法。

涡轮钻具是当前高温环境下（>250℃）可用的唯一孔底动力钻具，但由于其固有的软机械特性，在深孔硬岩地层中，钻头极易出现粘滑振动，导致涡轮钻具制动失速、钻进效率低、钻头和钻具损坏，甚至诱发孔内事故等问题。课题在开展涡轮钻进粘滑振动和减振机理研究的基础上，提出涡轮钻进抗粘滑振动、提高钻进速度、延长钻头和钻具使用寿命高效钻进技术。.首先，本项目考虑流体离心力场，基于修正的伯努利方程，建立了单级涡轮叶片和多级涡轮叶片的性能预测模型；针对高温地热的花岗岩地层特性，提出了叶片设计目标，根据无因次系数法和贝塞尔曲线设计理论，设计了外径为Φ89和Φ127涡轮叶片，并建立起多级涡轮仿真模型，对整个涡轮钻具输出性能进行了预测研究。研究结果表明：所用的设计方法可较好满足涡轮设计要求，多级仿真可有效提高性能预测的准确性。.随后，运用“灰箱”建模理论，建立涡轮钻具+孕镶金刚石钻头钻进传递函数模型；再利用摩擦学理论、非线性理论和金刚石钻进原理，研究孕镶金刚石钻头与典型硬岩相互作用机理，利用振动理论建立涡轮钻具水力部件-钻头（含取心筒）-岩石之间粘滑振动模型；利用涡轮实钻实验，建立起涡轮钻进抗粘滑和闭环钻井模型；以钻进速度和抗粘滑减振效果为优化目标，利用该模型为优化钻具结构参数、优化钻进工艺参数提供理论依据，进而提出适合深孔硬岩地层的涡轮钻进与取心工艺方法。