钻具过渡区探伤机理及工艺研究

发布时间：2018-02-14 03:10

本文关键词： 钻具过渡区超声相控阵技术腐蚀探伤　出处：《东北石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：石油钻杆是钻柱的重要组成部分,在使用过程中,常有疲劳和腐蚀裂纹等缺陷产生,如果不能及时检出,将导致刺穿或断裂事故,造成重大经济损失。根据国际钻井承包商协会钻杆失效分析统计,钻杆加厚区是易失效部位(70%~80%发生在加厚带),通常表现为裂纹、刺穿和断裂三种形式。目前国内外还没有检测机构对加重钻杆过渡区进行检测,需要建立一套完整和准确的加重钻杆过渡区工艺检测体系。本文对钻杆过渡区超声相控阵成像技术工艺和钻杆过渡区超声相控阵检测等方面进行分析和研究,采用理论计算钻具的应力集中系数,建立有限元模型,对钻杆内腐蚀缺陷、钻杆过渡区超声相控阵腐蚀成像技术、加重钻杆过渡区检测技术进行实验及分析。本论文从钻具的失效原因、失效过程及种类入手,通过计算钻具应力集中系数,建立有限元模型,并对其边界条件进行分析,随后通过计算管体抗拉强度和抗扭强度,分析腐蚀坑剩余强度与几何尺寸变化的规律。可知在腐蚀坑中,当深度相同时,坑底应力集中系数随蚀坑宽度的增加而减小;当宽度相同时,坑底应力集中系数随蚀坑深度的增加而增大。蚀坑的应力系数在1.5~2.5之间。为了研究钻杆过渡区超声相控阵腐蚀成像,本文引入了一种标定试块,帮助分析腐蚀成像,通过对钻杆过渡区缺陷进行实验,得出由于工件内表面不光滑和有比较大的曲率,机械加工人工孔使用数字游标卡尺测量值与使用超声测量值存在一定偏差测量值难以准确。在校准步骤中若需实际检测,校准工件一要与实际工件的尺寸、材料一致,表面要求比较平滑。在对加重钻杆过渡区检测进行研究时,本文通过制定总体思路,研究加重钻杆过渡区横向、周向探伤技术,并分析磁粉探伤的适用性及其方式。在对钻杆过渡区探伤进行实验研究时,选择合适的探头,如在对其进行横向探伤时,采用2.5P9×9 K2探头和5P9×9 K1探头的组合;在对其进行周向探伤时,采用2.5P9×9K1探头,增益为61.9 dB,通过对比实验可知在圆柱曲面周向探测时,弧长L水平距离l,深度Hd,其差值随d的增大而增大。在对磁场探伤进行分析时,选择线圈纵向磁化法作为钻具两端过渡区磁粉探伤方式。
[Abstract]:The oil drill pipe is an important part of the drill string. In the process of using, the defects such as fatigue and corrosion cracks often occur. If it is not detected in time, it will lead to puncture or fracture accident. According to the International Association of drilling contractors' failure analysis statistics, 70% of the drill pipe thickening area is prone to failure, and 80% occurs in the thickening zone, which is usually characterized by cracks. There are three forms of piercing and fracture. At present, there is no testing organization at home and abroad to detect the transition zone of heavy drill pipe. It is necessary to establish a set of complete and accurate technology detection system for the transition zone of heavy weight drill pipe. In this paper, the ultrasonic phased array imaging technology in the transition zone of drill pipe and the ultrasonic phased array detection in the transition zone of drill pipe are analyzed and studied. The stress concentration factor of drilling tool is calculated theoretically, and the finite element model is established. The ultrasonic phased array corrosion imaging technique is used to detect the corrosion defects in the drill pipe and the transition zone of the drill pipe. This paper starts with the failure reason, the failure process and the type of the drill tool, establishes the finite element model by calculating the stress concentration factor of the drill pipe, and analyzes the boundary condition of the drill pipe. Then by calculating the tensile strength and torsional strength of the pipe, the variation of residual strength and geometric size of the corrosion pit is analyzed. It is known that in the corrosion pit, the stress concentration factor of the bottom decreases with the increase of the width of the corrosion pit when the depth is the same. When the width is the same, the stress concentration factor increases with the depth of the pit. The stress coefficient of the pit is between 1.5 and 2.5. In order to study ultrasonic phased array corrosion imaging in the transition zone of drill pipe, a calibrated specimen is introduced in this paper. Through the experiments on the defects in the transition zone of the drill pipe, it is found that the inner surface of the workpiece is not smooth and has relatively large curvature. The measured value of digital Vernier caliper used in machining manual hole is difficult to be accurately measured with the measured value of ultrasonic. If the actual inspection is required in the calibration step, the calibrating workpiece must be consistent with the size and material of the actual workpiece. The surface requirement is relatively smooth. In the course of studying the detection of the transition zone of the heavier drill pipe, this paper studies the technology of transverse and circumferential flaw detection in the transition zone of the heavier drill pipe by making a general idea. The applicability and mode of magnetic particle flaw detection are analyzed. In the experimental study of drill pipe transition zone, the suitable probe is selected, such as 2.5P9 脳 9K2 probe and 5P9 脳 9K1 probe in transverse flaw detection. A 2.5 P9 脳 9K1 probe with a gain of 61.9 dB is used for circumferential flaw detection. The comparison experiment shows that the difference between the horizontal distance of arc length L and depth H _ d increases with the increase of d. In the analysis of magnetic field flaw detection, it is found that the distance of arc length L and the depth of H _ d increase with the increase of d in the circumferential detection of cylindrical curved surface. The coil longitudinal magnetization method is selected as the magnetic particle inspection method in the transition zone between the two ends of the drill tool.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE921.2

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