Experimental study on the working performance of different milling tools for multistage fracturing ball seats  

作　　者：Jia-Qi Che Han-Xiang Wang Yan-Wen Zhang Ming-Chao Du Shao-Hua Ma 

机构地区：[1]College of Mechanical and Electronic Engineering,China University of Petroleum(East China),Qingdao 266580,Shandong,People’s Republic of China

出　　处：《Petroleum Science》2020年第6期1699-1716,共18页石油科学（英文版）

基　　金：supported by the National Science and Technology Major Project under Grant Nos.2016ZX05042004 and 2017ZX05072;the Joint Funds of the National Natural Science Foundation of China under Grant No.U1762104;the Postgraduate Innovation Project Foundation under Grant No.YCX2019054;the Fundamental Research Funds for the Central Universities under Grant No.20CX02306A;the Opening Fund of National Engineering Laboratory of Offshore Geophysical and Exploration Equipment。

摘　　要：To achieve the secondary production in multistage fracturing wells of tight oil,milling tools are usually used to remove the multistage fracturing ball seats to achieve production with a large diameter in later.In this paper,first of all,the working mechanism of milling tools for multistage fracturing ball seats was studied and a mechanical analysis model of single abrasive grain was established.Then,an experimental system for milling tools was developed,and the experimental tests of the flat,the blade,and the slope milling tool were conducted in order.Besides,the morphology of chips and the surface morphology of the workpiece after the experiment were analyzed.Also,the working performance of milling tools was evaluated from the perspectives of working safety,working efficiency,and wear resistance of the milling tool.The results show that the torque of the milling tool increases nonlinearly with the increase in the cutting depth of the abrasive grain and increases linearly with the increase in the cutting width.Also,the chips are irregular particles and the size is mainly from 10 to 50μm.So,the chips should be pumped up with a small pump pressure and a large displacement.Besides this,the cutting depths of the abrasive grains are from 216.20 to 635.47μm and the bottom surface of the milling tool should be eccentric to avoid the zero point of cutting speed.Furthermore,the torque of the slope milling tool is 23.8%larger than that of the flat milling tool,which is also 30.4%smaller than that of the blade milling tool.Compared with the flat milling tool,the working efficiency of the blade milling tool improves by 79.9%and the slope milling tool improves by 111.1%.Also,the wear resistance of the blade milling tool decreases by 102.7%,while the slope milling tool declines by 32.6%when compared with the flat milling tool.Therefore,the slope milling tool has the characteristics of moderate torque,stable working conditions,the highest working efficiency,and fine wear resistance,which is preferably used to mill multistage

关 键 词：Multistage fracturing ball seat Milling tool Working performance Tight oil Experimental system Single abrasive grain 

分 类 号：TE934.2[石油与天然气工程—石油机械设备]