瞬变流诱发深层气井油管柱振动碰撞耦合机理研究

The high failure rate of tubing string in deep gas wells has caused serious safety risks and huge economic losses. The combined dynamical effect of tubing vibration and collision induced by transient flow is a major cause for tubing failure in deep gas wells. Based on the analysis of factors for tubing vibration-collision in deep gas wells, this paper will use transient flow theory, Euler-Bernoulli beam theory and Hamilton principle theory to establish a fluid-solid coupling theory model to simulate tubing vibration. Accordingly, the coupled interaction mechanism between tubing and fluid during tubing vibration-collision induced by transient flow will be studied systematically. Combined with force balance equation and velocity coordination equation on coupling contact surface, a dynamic theoretical model of tubing vibration-collision induced by transient flow in deep wells will be established. In consideration of the description of the coupling interface topology and the information transmission relation, the Lagrangian multiplier method will be used to solve the theoretical model numerically. Then the theoretical model will be validated and corrected according to down hole measured data and laboratory experimental data,. Finally, a set of research methods about the dynamic mechanisms of tubing vibration and collision will be formed. This research will provide theoretical support for tubing design and tubing failure prevention. Therefore, it will lay a theoretical foundation for the long-term integrity of deep gas wells.

深层气井普遍存在的油管柱高失效率问题造成了严峻安全风险和巨额经济损失，瞬变管流诱发的油管柱振动碰撞耦合动力学作用是深层气井油管柱失效的重要原因。本项目以深层气井油管柱振动碰撞各影响因素分析为基础，综合运用瞬变管流、Euler-Bernoulli梁和Hamilton原理等理论，建立瞬变管流诱发油管柱振动动力学全耦合理论模型，系统研究油管柱振动碰撞过程中油管柱内外流体与油管柱间全耦合作用机制，结合耦合接触面力平衡和速度协调方程，建立瞬变管流诱发深层气井油管柱振动碰撞耦合动力学模型。结合耦合界面拓扑结构和信息传递关系的描述，应用lagrangian乘子法对理论模型进行数值求解。应用井下实测数据和室内实验数据对理论模型进行验证和修正，最终形成一套油管柱振动碰撞耦合动力学机理研究方法，为油管柱优化设计、油管柱动力学损伤防治等提供理论依据，为保证深层气井长期完整性奠定理论基础。

深层气井普遍存在的油管柱高失效率问题造成了严峻安全风险和巨额经济损失，瞬变管流诱发的油管柱振动碰撞耦合动力学作用是深层气井油管柱失效的重要原因。本项目以塔里木油田克深区块油管失效问题的现场调研和分析为基础，基于井筒流体质量、动量、能量守恒及井筒传热理论，建立了考虑摩擦生热和对流换热等影响的不同测试工况下井筒压力温度场二维综合瞬态预测模型，通过差分离散和单点子域精细积分法求解相结合提出了一套新的井筒压力温度场瞬态预测模型求解方法；以完井管柱入井过程和坐封后受力状态精细模拟为基础，建立了深层高温高压气井封隔器管柱力学分析理论模型，在此基础上，充分考虑管柱内外流体压力、温度压力变化引起的轴向力、管柱自重、井口拉力。建立了全井段管柱屈曲构型模拟有限元仿真模型。综合运用瞬变管流、Euler-Bernoulli梁和Hamilton原理等理论，建立瞬变管流诱发油管柱振动动力学全耦合理论模型，系统研究油管柱振动碰撞过程中油管柱内外流体与油管柱间全耦合作用机制，结合耦合接触面力平衡和速度协调方程，建立瞬变管流诱发深层气井油管柱振动碰撞耦合动力学模型。结合耦合界面拓扑结构和信息传递关系的描述，应用lagrangian乘子法对理论模型进行数值求解。搭建了室内试验装置，并设计油管柱振动测试工具，通过室内试验和井下测试相结合，开展了其他诱发管柱振动的相关规律和井下管柱实际振动特性研究。应用井下实测数据和室内实验数据对理论模型进行验证和修正，最终形成一套油管柱振动碰撞耦合动力学机理研究方法，为油管柱优化设计、油管柱动力学损伤防治等提供理论依据，为保证深层气井长期完整性奠定理论基础。