普光气田气体钻井钻具失效原因分析及预防措施

Cause analysis and precautions of drilling tools failure during gas drilling in Puguang gas field

王文龙 赵勤 李子丰 刘东峰 张伟

WANG Wenlong ZHAO Qin LI Zifeng LIU Dongfeng ZHANG Wei

中原油田钻井工程技术研究院，河南濮阳　457001 中原油田钻井管具工程处，河南濮阳　457001 燕山大学，河北秦皇岛　066004

Drilling Engineering Technology Institute of Zhongyuan Oil Field, Puyang 457001, China Tubes and Tools Engineering Department of Zhongyuan Oil Field, Puyang 457001, China Yanshan University, Qinhuangdao 066004, China

气体钻井技术虽然大幅度提高了普光气田上部陆相地层钻井速度，但屡次出现钻具失效事故，不仅影响钻井速度，而且威胁井下安全。分析了钻具失效规律，并通过宏观分析判断钻杆为疲劳和腐蚀疲劳断裂，钻铤为疲劳断裂。从气体钻井自身因素、钻柱运动（包括公转和纵向共振）、钻具腐蚀、钻井方式、钻铤弯曲强度比不足等方面分析钻具失效原因，提出使用空气锤钻井技术、加强钻具探伤、优化钻具组合和钻井参数、缓解钻具腐蚀、加强钻柱振动监测等预防措施。指出应加强气体钻井钻具失效的微观机理、钻柱运动与动力学、岩屑对钻具的冲蚀磨损、钻具腐蚀、消除钻柱公转等方面的研究以预防钻具失效。

The drilling speed of the upper terrestrial formation in Puguang gas field has been increased remarkably, however, drilling tools failure occurs frequently. As a result, the drilling speed is influenced, and the downhole safety can not be guaranteed. At first, the failure rules are found out through statistical analysis. It is referred that the drilling pipe failure belongs to fatigue and corrosive fatigue fracture, while the drill collar failure is fatigue fracture. Then some preventive measures including using an air hammer, strengthening drilling tools flaw detection, optimizing bottomhole assembly and drilling parameters, preventing drilling tools corrosion, and strengthening the detection of the vibration of drill pipes are proposed, based on analyzing the causes of drilling tools failure, such as the self-factors of gas drilling, the movement of drill pipes（including rotation and vertical covibration）, the corrosion of drilling tools, the drilling way, and the insufficient flexural strength of drill collars. It is pointed out at last that the research and application of the micromechanism of drilling tools failure, the movement of drill pipes and kinematics, the erosion of drilling tools caused by cuttings, the corrosion of drilling tools, and the prevention of drill pipes rotation should be strengthened. As well overall analysis and prevention of drilling tools failure should be intensified.