射流磨钻头流场特性及其外排屑槽影响的数值模拟  

Numerical simulation on the flow field characteristics of jet mill bit and the influence of its external cuttings drainage channel

作　　者：陈绪跃[1,2] 曹通 高德利 杨进[1] 刘明涛[3] 杨书港[3] CHEN Xuyue;CAO Tong;GAO Deli;YANG Jin;LIU Mingtao;YANG Shugang(Key Laboratory of Petroleum Engineering,the Ministry of Education,China University of Petroleum(Beijing),Beijing 102249,China;Shaanxi Cooperative Innovation Center of Unconventional Oil and Gas(Xi’an Shiyou University),Xi’an 710065,Shaanxi,China;Drilling and Production Technology Research Institute,PetroChina Liaohe Oilfield Company,Panjin 124008,Liaoning,China)

机构地区：[1]中国石油大学(北京)石油工程教育部重点实验室,102249 [2]陕西省非常规油气勘探开发协同创新中心(西安石油大学 [3]辽河油田分公司钻采工艺研究院

出　　处：《石油钻采工艺》2020年第2期162-166,共5页Oil Drilling & Production Technology

基　　金：国家自然科学基金青年项目“水平井射流磨钻头粉碎钻屑与提高钻速的机理研究”(编号:51804322);陕西省非常规油气勘探开发协同创新中心(西安石油大学)开放基金资助项目“非常规油气水平井射流磨钻头高效破岩技术研究”(编号:SXCU-201903)。

摘　　要：在油气田开发中,水平井钻进时携岩困难、托压严重、机械钻速慢等问题严重影响生产效益。射流磨钻头既能降低井底压差实现欠平衡提速,又能粉碎岩屑实现岩屑悬浮运移,为水平井安全高效钻井作业提供技术支撑。研究基于计算流体力学方法,建立了射流磨钻头流场的数值仿真,并采用标准k-ε双方程模型对其流场特性及其外排屑槽尺寸的影响进行了模拟研究。结果表明,无外排屑槽时射流磨钻头的降压效果最好,井底低压区和中压区呈现一降一升的趋势;井底压力沿钻头直径方向分布极不均匀,高压与低压交错出现;在开外部排屑槽的情况下,内排屑孔的总体积流量占比达100%以上,随单个外排屑槽宽度的增大,内排屑孔的总体积流量占比增加,且外排屑槽存在钻井液回流的现象,回流体积流量占比4%以内。研究结果为射流磨钻头的优化设计与应用提供理论依据。In the process of oil and gas field development,some problems occur during the drilling of horizontal wells,e.g.difficult cuttings carrying,severe backing pressure and low rate of penetration(ROP),which seriously impact production benefits.The jet mill bit can not only reduce the bottom hole pressure difference to realize the underbalanced ROP improvement,but also crush the cuttings to realize suspended cuttings transportation,so as to provide the technical support for the safe and efficient drilling of horizontal wells.The numerical simulation model for the flow field of jet mill bit was established on the basis of fluid dynamics calculation method.Then,the flow field characteristics of jet mill bit and the influences of the size of its external cuttings drainage channel were numerically simulated by means of the standard k-εtwo-equation model.It is indicated that when there is no external cuttings drainage channel,the depressurization effect of the jet mill bit is the best and the low-and middle-pressure zones at the bottom hole present the trend of one decreasing and one increasing.In addition,the distribution of bottom hole pressure along the diameter direction is extremely uneven,and high pressure and low pressure are crisscrossed.When the external cuttings drainage channel is opened,the bulk volume flow ratio of the internal cuttings drainage hole is over 100%.As the width of single external cuttings drainage channel increases,the bulk volume flow ratio of the internal cuttings drainage hole increases.Besides,the phenomenon of drilling fluid backflow occurs in the external cuttings drainage channel with the backflow volume flow ratio basically below 4%.The research results provide the theoretical basis for the optimal design and application of jet mill bit.

关 键 词：射流磨钻头 水力结构 井底流场 数值模拟 

分 类 号：TE21[石油与天然气工程—油气井工程]