随钻测井仪器的舱槽变形分析及优化设计

Deformation analysis and optimization design on cabin-slot of logging while drilling

针对随钻测井仪器在现场应用过程中,出现测传舱体的舱槽变形而导致仪器失效的实际问题,对其失效位置、特性及原因等方面进行了总结与分析。分析得出:在材料性能满足要求的条件下,舱体在井下受振动、动态转矩、高温高压等复杂工况下的交变载荷及钻井液冲蚀、内压的多重作用,舱槽底部薄弱区逐渐形成应力集中,从而增大了舱槽变形的风险。为此,建立测井仪器舱体的力学分析模型,并结合实例计算及不同舱槽结构下的应力分析,优化和改进了舱体的舱槽结构设计。通过现场试验及推广应用,结果表明舱槽结构的优化有效避免了舱槽的变形,显著提升了舱体的使用寿命。

Since the logging while drilling(LWD) fails due to deformation of the cabin-slot in the field application,in this article,the failure location,characteristics and causes are summarized and analyzed.The results show that when the materials performance meet the requirements,the measuring cabin is subjected to alternating load,drilling fluid erosion,internal pressure and other multiple effects under such complex working conditions as vibration,dynamic torque,high temperature and high pressure,thus gradually forming stress concentration in the weak area at the bottom of the cabin-slot and increasing the risk of cabin-slot deformation.To this end,the model of mechanical analysis on the logging while drilling’s cabin-slot is set up,and the structure design of the measuring cabin is optimized and improved by means of calculation and stress analysis with different cabin-slot structures.The field test and application show that optimization of the cabin-slot structure effectively avoids cabin-slot deformation and significantly improves the measuring cabin’s service life.