自动垂直钻井系统BHA力学分析的一维模型

为了指导自动垂直钻井工具的研发和现场应用,并且为自动垂直钻井系统底部钻具组合的优化设计提供理论依据,在充分调研自动垂直钻井系统的结构特征、工作原理的基础上,用纵横弯曲法建立了加装自动垂直钻井工具的BHA的一维力学分析模型,建立了自动垂直钻井系统的BHA的普遍力学方程。确定了钻头和上切点处的边界条件,推导出钻头侧向力和钻头转角的计算公式。应用所建立的力学模型能准确地计算出稳定器支点的内弯矩和梁柱各点处的挠度,同时也可以计算出一定工作条件下的钻头侧向力和钻头转角,通过分析钻头侧向力和钻头转角随钻进参数的变化规律可以分析钻进参数对自动垂直钻井工具造斜能力的影响规律,为指导自动垂直钻井工具的现场使用提供理论依据。

One dimensional mechanics analysis model of Bottom Hole Assembly of automatic vertical drilling system

To guide development and application of automatic vertical drilling tools and provide theoretical basis for optimum design of bottom hole assembly of automatic vertical drilling system,the one dimensional(1-D) mechanics analysis model of bottom hole assembly(BHA) equipped with automatic vertical drilling tools is developed by using the beam-column method,the general dynamics equation of BHA is established,boundary conditions at bits and the upper tangent are determined,and the formula is deduced for calculating lateral forces and deflection angles of bits,based on the research of structural features and work principle of automatic vertical drilling system.By applying the model,the bending moment of stabilizer pivots and the bending deflection of the beam column can be exactly calculated.Meanwhile,the law of lateral forces and deflection angles of bits changing with drilling parameters can also be used to analyze the effect of the drilling parameters on deflecting forces of automatic vertical drilling tools,providing theoretic basis for directing field application of automatic vertical tools.