钻井过程井筒温度动态特性研究及影响因素分析

Research on Dynamic Characteristics of Wellbore Temperature During Drilling and Analysis of Its Influencing Factors

井筒温度和传热分布对于井筒压力控制、泥浆性质、井壁稳定以及钻井工具特性有重要的影响.因此准确的预测井筒温度动态特性对于安全高效钻井有着重要意义.在前人研究基础上,基于井筒动态机理模型研究了井底和环空出口处钻井液温度随时间变化规律以及分析了当入口钻井液流速、比热等参数变化时,井底和环空出口钻井液温度变化趋势.研究表明在循环过程中,井底和环空出口温度逐步达到稳定值,当钻井液入口流量增大时,井底温度达到稳定值时间减小,井底温度几乎保持不变;降低钻井液入口比热容,井底温度达到稳定值时间增加,井底温度降低.

Wellbore temperature and heat transfer distribution play an important role in wellbore pressure control,mud properties,wellbore stability and drilling tool characteristics.Therefore,accurate prediction of wellbore temperature dynamic characteristics is of great significance for safe and efficient drilling.In this paper,on the basis of previous studies,the variation rule of drilling fluid temperature with time at the bottom of the well and at the annulus outlet is studied based on the wellbore dynamic mechanism model.It also analyzes the changing trend of bottom hole and annulus outlet drilling fluid temperature when the parameters such as inlet drilling fluid velocity and specific heat change.The results show that the bottom hole and annulus outlet temperature gradually reach a stable value in the process of circulation.When the inlet flow of drilling fluid increases,the time for the bottom hole temperature to reach a stable value decreases,and the bottom hole temperature almost remains unchanged.When the specific heat capacity of the drilling fluid inlet is reduced,the time for the bottom hole temperature to reach a stable value increases,and the bottom hole temperature decreases.