扭转冲击钻井稳态钻进动力学特性及现场应用

Dynamic characteristics of steady torsional impact drilling and its field application

关键词:  钻井  PDC钻头  动力学特性  稳态钻进  钻速  现场应用

Key words:  drilling  PDC bits  dynamic characteristics  steady drilling  penetration rate  field application

摘要:

为了解决PDC钻头在深井钻进时出现的黏滑效应问题,提出扭转冲击钻井提速技术。保持该技术在稳定的工作状态是提速的关键。为研究扭转冲击钻井稳态钻进时的动力学特性,基于振动学理论,建立考虑钻杆能量耗散的扭转冲击钻井系统力学模型,基于稳态钻进条件对力学模型求解,分析模型特征参数对冲击系统动力学特性的影响规律,最后通过扭转冲击工具的现场应用实例进一步验证扭转冲击钻井稳态钻进的提速效果。结果表明:高钻压低转速配合优选的PDC钻头有利于扭转冲击钻井稳态钻进;钻柱的阻尼和刚度分别有利于扭转切削运动和轴向钻进运动;钻头与岩石相互作用特征参数对扭转冲击钻井稳态钻进影响不明显。文安M井应用实例表明扭转冲击钻井稳态钻进可减缓PDC钻头磨损、显著提高机械钻速。

Abstract:

A torsional impact drilling technique is proposed to reduce the stick-slip effect of PDC bits when it is used in deep oil and gas wells, which can be applied for improving the rate of penetration. In order to study the dynamic characteristics of the torsional impact drilling, a drill string dynamics model, considering the energy dissipation of the drill pipe, was presented based on the vibration theory. The dynamics model was solved under a steady drilling condition, and then the influences of operation parameters on the dynamic characteristics of impact system were analyzed. The effect of the technique on increasing the penetration rate during steady torsional impact drilling was verified by case studies of field applications. The results show that a combination of high weight on bit (WOB) and low rotation speed with selected PDC bits is beneficial for the application of the torsional impact drilling. The damping and stiffness of drill string are also beneficial to the torsional cutting and axial penetration movements of the drill bit. The characteristic parameters of the interaction between drill bit and rock have no obvious effect on the steady torsional impact drilling. The case study of Wen 'an M well shows that the steady torsional impact drilling can reduce the wear of PDC bits and significantly improve the rate of penetration.