Study On Dynamic Buckling Of Pipe String During Sliding And Hitting Bottom Hole In Directional Well Section

At present,our country has opened a new journey of comprehensive modern socialist power,for the survival and development of the indispensable oil resources is particularly important.In order to meet the country’s urgent need for petroleum resources,directional well drilling and production technology has been improved and improved in continuous practice,which provides unlimited support and inexhaustible power for the long-term development of China’s petroleum industry.During drilling and oil production,the drill string,casing string,sucker string,coiled tubing and other operating strings occasionally break off due to improper design or operation errors,slide down the well-bore and hit the bottom of the well.In the process of sliding,the pipe string will be buckled or even plastic deformation due to friction,dynamic buckling or even plastic deformation due to the reaction force at the bottom of the well when it hits the bottom of the well,and even plastic deformation will occur.All these will lead to the pipe string stuck in the well-bore,resulting in the scrapping of the well-bore and slowing down the mining progress.Therefore,it is necessary to deeply study the dynamic buckling behavior of string during drilling and oil recovery when it slips and hits the bottom hole.The effect of these three parameters on the dynamic buckling of the string during well-bore slip.After investigating the research status of domestic and foreign scholars in the three aspects of string buckling,impact dynamics and the application of simulation software in the dynamic buckling of string.Finding that little research has been done on the sliding and bottom-hole impact of broken strings.However,the field experiment conditions are limited,so we decided to use ABAQUS commercial finite element software to simulate the whole process of string sliding and impact dynamic buckling at the bottom of the hole.The string slippage model and the string impact bottom hole model based on the trajectory parameters of the three-opening hole were established in ABAQUS commercial finite element software.In the casing slip model,the well-bore friction coefficientμ=0.1,0.2,0.3,and the casing length L=200m,500 m,1000m,respectively,the well type is horizontal well and ordinary directional well.The data of slip sounding,slip velocity and axial stress are analyzed.In the model of string impact on bottom hole,the length of slip string L=100m,200 m,500m,and the length of well-bore L=1000m,2000 m,3000m,respectively,the well types are vertical well and oblique straight well.The influence of these three parameters on the dynamic buckling of the string during the impact on the bottom hole.And in the process of impact of string axial displacement,axial velocity and the axial stress change rule of data analysis and summary.