The Drilling Tools Failure Analysis And Inspection Research In LiaoHe Oilfield

The drilling tools sustain complex stress and have harsh service conditions in downhole.The drill string will suffer from a great influence on stress alternating load,temperature,ambient medium,friction between drill string and borehole wall,high frequency impact,corrosion and hydrogen embrittlement,etc.,and easily cause a variety of drilling tools failure accidents.Once happened a failure accident,the loss can be rather serious.By taking effective measures to prevent drilling tools failure is of great significance.Researching and analyzing the drilling tools failure,finding out the main reason and mechanism of drilling tools failure,and judging their failure parts through the corresponding inspection technology in advance,then determining the using state of drilling tools,it's convenient for us to use and maintain tools well,so that we can provide strong safeguard for preventing down-hole equipment failure,reducing accident loss and strengthening the drilling competitive power.Firstly this paper has carried on the statistics and researched the drilling tools failure situations of Liaohe oilfield,the studies have shown that fatigue is the main reason which causes the failure of the drilling tools,and drilling tools surface stress concentration areas are prone to fatigue failure conditions.The data shows that the drill pipe and drill collar failure accidents accounted for 84.7% of the total number,the thread parts are the key accidents point,and most of these failure accidents are associated with fatigue.Then research the effect and applicability of the drilling tools failure detection in view of the current 5 kinds of detection means in Liaohe oilfield.By studying the application on the spot,founding that thread detection mainly uses the ultrasonic testing method,the pipe body detection mainly adopts integral magnetic flux leakage testing equipment for testing,but these methods are dependent on inspectors who have certain experience,and ultrasonic testing can not automatically test the morphology of thread.Based on the situation,this paper puts forward to design a set of drill pipe automatic testing system.The testing system includes 6 parts:the first part is drilling recycling unit,it can be used to store different sizes and types of drill pipes respectively,convenient for the later testing;The second part is the automatic straightening drill pipe,to achieve the drill pipe straightness inspection and automatic straightening;The third part is the pipe leakage detection,the same as the current detection system;The fourth part is the automatic cleaning thread,it designs a cleaning device,which can clean the thread of the drilling tools,remove the sludge and otherdirt of the screw thread on the surface,making the thread surface keeping bright and clean;The fifth part is the thread detection,this paper puts forward the image detection system based on digital processing,which can quickly and accurately determine the thread,test the thread morphology;The final part is drill pipe classifying,which is controlled by the PLC,comprehensively analyze the test results of the pipe and thread,and then conclude the level of drill pipe and automatically sent to the corresponding pipe rack for storage.