CAJ | 학술논문

双台肩钻杆接头具有大幅度提高抗扭强度、增大水眼的优势，对此类钻杆接头的失效进行分析，具有规范使用操作或改善接头结构性能的意义。某井在双台肩钻杆接头使用中发生两起接头刺漏失效事故，为查明刺漏失效原因，对其中1支刺漏接头进行分析，包括刺漏冲蚀形貌宏微观观察、化学成分分析、力学性能测试及受力情况模拟。分析结果认为：钻杆接头发生刺漏冲蚀原因主要是接头上扣扭矩不足导致接头主台肩面接触压力不足，螺纹疲劳强度下降，螺纹牙底因应力集中形成多源疲劳裂纹，最终高压泥浆从副台肩及刺穿的裂纹冲蚀出。建议钻具使用时按照推荐的上扣扭矩进行上扣，避免类似的情况再次发生。
쌍태견찬간접두구유대폭도제고항뉴강도、증대수안적우세，대차류찬간접두적실효진행분석，구유규범사용조작혹개선접두결구성능적의의。모정재쌍태견찬간접두사용중발생량기접두자루실효사고，위사명자루실효원인，대기중1지자루접두진행분석，포괄자루충식형모굉미관관찰、화학성분분석、역학성능측시급수력정황모의。분석결과인위：찬간접두발생자루충식원인주요시접두상구뉴구불족도치접두주태견면접촉압력불족，라문피로강도하강，라문아저인응력집중형성다원피로렬문，최종고압니장종부태견급자천적렬문충식출。건의찬구사용시안조추천적상구뉴구진행상구，피면유사적정황재차발생。
In comparison with API drill rod joints, double-shoulder drill rod joints have higher tensional strength and bigger hydrophthalmia. Two double-shoulder drill rod joints were found to have pricking holes during service. In order to find out the failure cause, failure analysis was performed on one drill rod joint by macro and micro morphology analysis, chemical composition test, mechanical property test, metallographic examination and finite element stress analysis. The results show that lower make-up torque resulted in lower contact pressure of the main shoulder and the reduction of thread fatigue strength. Multisource fatigue cracks formed at the root of thread due to stress concentration. Finally, the high pressure drill mud run out from the secondary shoulder and through cracks. It is suggested that recommended make-up torque should be applied on double shoulder drill rod joint before using in well drilling.