摘要
钻杆刺漏是渤海油田深井钻进过程中存在的难题,严重影响钻进效率。通过对渤海刺漏井失效原因的统计分析,建立了考虑钻杆本体与井壁接触方式及轴向振动的疲劳寿命预测模型。探讨了初始裂纹形态和尺寸对钻杆疲劳寿命的影响规律。研究表明,钻杆刺漏主要是由钻杆疲劳破坏引起的,钻杆表面的初始微裂纹在交变载荷的作用下扩展而导致钻杆刺漏;当线性裂纹和半椭圆形裂纹的尺寸相近时,表面为线性裂纹的钻杆寿命更短,表面半椭圆形裂纹钻杆的疲劳寿命与b0/a0有关,b0/a0越大,寿命越长,其对初始裂纹长度比较敏感。
Drill pipe washout is a challenge during deep drilling at Bohai oilfield,which seriously affects the drilling performance.By statistical analysis of the washout causes,a fatigue life prediction model was established,the drill pipe/sidewall contact and axial vibration considered.The influence of initial fracture pattern and size,borehole curvature,hook load and WOB fluctuation on drill pipe fatigue life is discussed.The research shows that drill pipe washout is mainly caused by fatigue failure,the initial micro cracks on surface will expand and wash out under the alternating loads.The calculation results of drill pipe fatigue life prediction model indicate that if linear crack size is close to semi elliptical crack size,the drill pipe with linear crack is shorter in life.The fatigue life of drill pipe with semi elliptical crack is related to b0/a0,the bigger the b0a0is,the longer the drill pipe s life.And initial crack length also has a sensitive effect on the life.With the increase in borehole curvature,the drill pipe life decreases exponentially.The fatigue life of drill pipe in borehole curvature 6°/30m is 25% of that in borehole curvature 4°/30m.The hook load and WOB fluctuation also affect drill pipe life,with hook load and WOB fluctuation increased,the fatigue life reduced.This study will be a guide to rational use of drill pipe in deep wells.
作者
许杰
林海
霍宏博
谢涛
何瑞兵
XU Jie;LIN Hai;HUO Hongbo;XIE Tao;HE Ruibing(CNOOC Tianjin Branch, Tianjin 300451, China;State Key Laboratory of Offshore Oil Exploitation, CNOOC Tianjin Branch, Tianjin 300451,China)
出处
《钻采工艺》
CAS
北大核心
2018年第6期23-26,126,共5页
Drilling & Production Technology
基金
国家科技重大专项“渤海油田高效开发示范工程”(编号:2016ZX05058)。
关键词
钻杆刺漏
失效分析
裂纹扩展
疲劳寿命
预测模型
drill pipe washout
failure analysis
crack growth
fatigue life
prediction model
