Failure Analysis And Prevention Of Drill Pipe In Oil & Gas Pipeline Crossing

Drill pipe has a pivotal role in the drilling process,it was used to transmit the torque from a drill to a rig to achieve drilling. In the drilling process,the drill pipe will withstand a very complex dynamic load,it is almost at the same time withstand the tensile stress,compressive stress,torsional stress,bending stress and so on. In the guide or directional drilling process,it will have a serious impact on the project when the drill pipe has a certain degree of failure. Not only does it will lead to a huge economic loss,but also will affect the speed of drilling and delay the drilling schedule. This will enable customers to lose credibility for the company’s products. And the consequences could be disastrous. Therefore,It is very necessary to do some analysis of the drill pipe to identify the cause of failure,And take some corrective or preventive measures to prevent the recurrence of similar failures or limit the failure of the product within a predetermined range to avoid an early failure so that the drilling work will be carried out smoothly. At the same time,it will bring huge economic benefits and good reputation to the company to improve the quality of drill pipe. And thus can get some great social benefits.This paper mainly studied and analyzed the failure reason and prevention of no dig drill pipe from three aspects. The three aspects are the failure of drill pipe joints,the failure of drill pipe body and the ultrasonic flaw detection of drill pipe joints. The main work is as follows:1) Some basic failure forms of drill pipe joints and prevention measures are introduced. And according to the current application of laser hardening technology in strengthening the drill pipe joint,the laser quenching technique are introduced,because there is a great superheat and subcooling in laser quenching process which makes the hardened layer with very fine grain,high dislocation density and form a compressive stress in the surface layer. They can greatly improve the performance of drill pipe thread, Including abrasion resistance, fatigue resistance,corrosion resistance,anti-oxidation and other properties,so that to prolong the service life of drill pipe thread.2) Combined with the common fracture of drill thread joint and thread-galling failure in the construction site,fracture reason of two drill pipe thread joint during drill process was analysed by physical and chemical performance test. Because there are many factors that can cause the drill pipe joint thread galling. It is also a common failure mode that troubles the drill pipe manufacturers and construction units. Therefore,the causes and prevention measure that may lead to the drill pipe joint thread galling are introduced from the two aspects of the manufacturers and the field operation in this paper to reduce the occurrence of such failure.3) Some causes that may lead to drill pipe fracture are introduced respectively from two aspects of construction and production. And some corresponding prevention measures are proposed. Then,the main reasons may make the drill rod fracture in the process of large diameter pipelines crossing are introduced. And here are some measures to prevent such failure. Finally,the failure analysis of fracture cause of a drill pipe was carried out.4) The geometry of the drill pipe joints is entirely different from the drill rod. And the phenomenon of stress concentration in this part is very obvious. Under the action of complex alternating stress,here is extremely easy to be a fatigue crack initiation site. Therefore,the regular detection of the fatigue crack of drill pipe thread parts can prevent the drill pipe rupture accident caused by this. The paper also did some introduction about the characteristics and the detection methods and principles of the fatigue cracks of the drill pipe thread parts. And combined with the actual contrast test block,Three grooves were pre-made at the root of the second to the third thread of the external thread of the drill pipe. Their length is 20 mm,the width is 0.6mm,the depth is in turn 1mm,2mm,3mm. The determination of location and indicating length of these defects was done by ultrasonic flaw detector. And the determination of the location and length of crack defect of drill pipe thread parts can be realized by the ultrasonic flaw detector which was verified. And the error is within a certain range of reasonable. Finally,the flaw detection in the inner surface of the external thread joint of the drill pipe is recommended to try. And there is no mention of the application of this detection method at present. This method is using the first wave. And the accuracy of flaw detection could be higher in theory.5) Combined with what I saw and heard in the drill production site during the internship,A simple induction and summary for the potential causes of failure may exist in the process of drill pipe production has been carried out simply. And the corresponding prevention measures and the suggestions or opinions for improving are given.