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Yikuang Technology Drill Pipe Manufacturers Launch-Measures to Avoid Abnormal Failure of Drill Pipe
Release time:
2019-07-23
Author:
Source:
Shandong Yikuang Drilling Technology Co., Ltd. produces all kinds of geological drill pipes, spiral drill pipes, triangular heavy-duty grooved drill pipes, special-shaped multi-angular grooved drill pipes, coal drill pipes, drill bits, drill pipes, etc., with complete specifications! Strength manufacturers, trustworthy! company set research and development-production-sales-sales as one, welcome customers to purchase, tel: 0635-2311078
The basic mechanics of the drill pipe: the drill pipe works in a long and narrow borehole filled with drilling fluid inside and outside, and usually bears loads such as compression, bending, torsion and hydraulic pressure. If the stress on the drill pipe is less than 206.8 Newtons per square meter, the drill pipe will not produce fatigue cracks although it has been bent countless times. During drilling, the drill pipe is subjected to a large composite stress consisting of bending, torsion and tensile stress, especially in large displacement directional wells and horizontal wells, the torque is extremely large, and fatigue micro-cracks will occur when the drill pipe is bent for 1 million times. The micro-cracks will continue to expand and extend after they occur. At this time, if high-pressure drilling fluid with corrosion effect enters into the micro-cracks, it will accelerate the crack propagation and eventually lead to the failure of drilling fluid piercing drill pipe. As a result of the development of piercing, the effective section of the drill pipe is continuously reduced, and when the total length of the puncture and crack exceeds its critical crack size, fracture occurs. In addition to the downward movement of the rotation, there are various vibrations and whirls of the drill pipe.
According to the analysis of the failure causes of drill pipes, the abnormal failure causes of drill pipes can be divided into two aspects: the operation reasons of workers and the quality reasons of drill pipes themselves. Therefore, we can avoid abnormal failure of drill pipe from improving the quality of drill pipe and standardizing operation.
improve the quality of drill pipe
(1) Drill pipe material selection: In order to adapt to the force analysis of the drill pipe, the drill pipe body should have high tensile strength, good bending performance and good impact toughness. The rod body material should be selected in the carbon alloy structure of seamless steel pipe, alloy elements should contain more Cr, Mo and other elements to improve the tensile strength and impact toughness of the material, containing Mn, Si and other elements to improve the elasticity of the material (I. e. bending performance). Sometimes it also contains trace elements such as B and V to improve the hardenability of the material.
Commonly used rod body materials are: R90, R780, DZ50, DZ40, 36Mn2V>35CrMo>42MnlMo7>35CrMnSi, 45MnMoB, etc.
The wall thickness uniformity and rolling defects of seamless steel pipes used for rod bodies are also important factors affecting the quality of drill pipes. For example, the uneven wall thickness of the rolled steel pipe is serious, and when the drill pipe has a large torsion force, it is easy to crack longitudinally at the thinner wall thickness. Some steel pipes have defects such as heavy skin and air holes, and drill pipes are easy to produce stress concentration fracture or puncture leakage from here.
Drill pipe joints are the most complex force, the joint material must have a high comprehensive mechanical properties. Drill pipe joints are mostly made of 35CrMo or 42CrMo.30CrMnSiA bar stock, but the forged joint material can greatly improve its comprehensive mechanical properties.
(2) Processing technology selection: At present, the domestic drill pipe from the processing technology is divided into the whole forging drill pipe (referred to as the whole drill pipe), friction welding drill pipe (referred to as the British drill pipe).
(3) The surface treatment of the screw thread: The surface nitriding treatment of the screw thread can effectively prevent the screw thread, and can also improve the wear resistance of the screw thread, thereby increasing its service life. Nitriding layer thickness is generally 0.2~0.3mm, the thickness is too large easy to produce broken cracks, the thickness is too small, the anti galling effect is poor. The whole drill pipe cannot be nitrided and is replaced by phosphating with a much smaller layer thickness.
(4) thread machining accuracy: the joint thread should be processed with a forming thread turning tool on a CNC lathe. The surface quality of the thread should be improved as much as possible, the surface roughness value (Ral.6pm) should be reduced, the smoothness should be improved, the stress concentration should be reduced, and the interchangeability of the drill pipe should be ensured. The thread tightness of the joint shall be controlled within a reasonable range to ensure good thread engagement.
Shandong Yikuang Drilling Technology Co., Ltd. produces all kinds of geological drill pipes, spiral drill pipes, triangular heavy-duty grooved drill pipes, special-shaped multi-angular grooved drill pipes, coal drill pipes, drill bits, drill pipes, etc., with complete specifications! Strength manufacturers, trustworthy! company set research and development-production-sales-sales as one, welcome customers to purchase, tel: 0635-2311078
Key words:
Drill pipe, geological drill pipe, spiral drill pipe, triangular drill pipe, new coal drill pipe, rib drill pipe
