一例钻柱稳定器断裂原因分析及措施

为防止类似南海西部油气田因稳定器断裂造成的钻井事故再次发生,确保钻井安全和作业时效。以该区块的某探井为例,对2起稳定器断裂事故进行了阐述。基于简支梁模型对钻柱“A-B”危险截面进行了受力分析,同时对试件宏观断口形貌与金相组织进行了观察。分析结果表明:切片金相组织符合原材料热处理工艺要求,螺纹牙底疲劳裂纹是造成稳定器断裂的根本原因。提出了增加稳定器打捞外径、肩部钎焊PDC齿2种方法,优化稳定器结构,改善稳定器承载能力。钻柱“A-B”截面交变应力破坏具有较大的风险,在设计中需要予以充分重视。

Cause Analysis and Measures for a Case of Drill String Stabilizer

In order to prevent the drilling accidents caused by the fracture of stabilizer in the western South China Sea oil and gas fields and to ensure the safety of drilling operation, an exploratory well was taken as an example and two faults of stabilizer in the well were described. Based on the simple support beam model, the stress analysis of the " A-B " dangerous section of the drill string was analyzed while the macroscopic fracture morphology and metallographic structure of the sample were observed. The results show that the section of the metallographic tissue conforms to the requirements of the heat treatment process of raw materials. The fatigue crack on the bottom of screw thread is the fundamental cause of fracture of the stabilizer. Two improvement methods of the stabilizer structure and the carrying capacity of the stabilizer by increasing the diameter of the stabilizer and shoulder brazing at the PDC teeth were introduced.