渤中19-6构造下部钻具组合动力学特性

Dynamic characteristics of bottom hole assembly in Bozhong 19-6 structure

谢涛 邓建明 张磊 袁伟伟 岳明 徐涛

XIE Tao DENG Jianming ZHANG Lei YUAN Weiwei YUE Ming XU Tao

中海石油(中国)有限公司天津分公司 海洋石油高效开发国家重点实验室

Tianjin Branch of China National Offshore Oil Co., Ltd., Tianjin 300459, China State Key Laboratory of Offshore Oil Exploitation, Tianjin 300459, China

渤中19-6构造深井钻探时，Ø406.4 mm井眼利用PDC和Power V钻具组合钻进到2 841 m处，出现了扭矩增加、悬重降低的复杂情况，起钻后发现马达上活塞套筒与直壳体连接处发生断裂，严重耗损钻井工期与费用。为揭示下部钻具组合局部应力分布，基于Abaqus有限元分析软件建立了下部钻具组合-钻头-地层三维有限元模型，利用真实井下工况参数、采用显式时间积分法进行模拟求解，分析了下部钻具组合受力情况。结果表明，马达上存在应力集中点，应力随时间呈现周期循环往复状态，符合疲劳破坏的特征，且集中点基本与断裂位置重合，验证了本模型的准确性。该模型对于渤中构造深井的下部钻具组合动力学分析具有一定的指导意义。

During deep-well drilling in Bozhong 19-6 structure, complicated situations of torque increasing and hanging load decreasing appeared when Ø406.4 mm borehole drilled to the depth of 2 841 m by using the bottom hole assembly (BHA) of PDC and power V.After it was pulled out of the hole, the connection between the piston sleeve and the straight shell of the motor was found to be fractured, which seriously wasted drilling time and cost.In order to reveal local stress distribution of BHA, a three-dimensional finite element model of BHA-bit-formation was established on the basis of ABAQUS software.Then, based on the parameters of actual downhole working condition, the model was solved by means of explicit time integration method.Finally, the stress applied on BHA was analyzed.It is shown that there is a stress concentration point on the motor, and stress appears periodically and repeatedly over the time, which conforms to the characteristics of fatigue failure.Furthermore, the concentration point basically coincides with the fracturing location, which verifies the accuracy of the model.The model is of some guiding significance to the dynamic analysis on the BHA of deep wells in Bozhong structure.

10.13639/j.odpt.2018.S0.030