Study on dynamic response and failure mechanism of tubing string under pressure during the whole perforation process
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摘要: 针对超深井射孔作业中瞬态压力波动引发管柱及井下工具失效的工程难题,本文突破单一峰值载荷研究的局限,以射孔全过程压力瞬态演化模拟为基础,建立耦合爆轰压力与动态负压全周期效应的射孔管柱动力学模型。采用准噶尔盆地X1井的现场试验数据完成模型精度验证,理论计算与实测加速度数据峰值相对误差为8.62%,表明模型能够较好捕捉射孔初期强冲击阶段的加速度峰值与主要振荡特征。以四川盆地某超深井为例,系统剖析了射孔管柱应力波的传播演化特征、加速度响应规律及其对关键工艺参数的敏感性。研究表明:爆轰压力峰值直接主导管柱的轴向压缩应力水平,而动态负压谷值则对轴向拉伸应力具有决定性影响;应力波在封隔器固定端发生强烈反射与叠加,使封隔器及邻近连接区域成为拉伸峰值放大、螺纹连接失效和封隔器中心管损伤的高风险区。本研究从载荷演化、动态响应到失效风险识别构建了较为完整的分析框架,可为射孔全过程管柱完整性评价提供理论依据。
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关键词:
Abstract: To address the engineering problem of tubing-string and downhole-tool failures induced by transient pressure fluctuations during perforating operations in ultra-deep wells, this study moves beyond the limitation of analyses based on a single peak load. On the basis of transient pressure evolution simulation throughout the entire perforation process, a dynamic model of the perforating string is established by coupling the full-cycle effects of detonation pressure and dynamic underbalance pressure. Field test data from Well X1 in the Junggar Basin are used to validate the model accuracy. The relative error between the calculated and measured acceleration peaks is 8.62%, indicating that the model can effectively capture the acceleration peak and main oscillation characteristics during the early strong-impact stage of perforation. Taking an ultra-deep well in the Sichuan Basin as an example, the propagation and evolution characteristics of stress waves in the perforating string, the acceleration response behavior, and their sensitivity to key operating parameters are systematically analyzed. The results show that the detonation pressure peak directly governs the axial compressive stress level of the string, whereas the dynamic underbalance pressure trough plays a decisive role in axial tensile stress. Strong reflection and superposition of stress waves occur at the fixed packer end, making the packer and adjacent connection regions high-risk zones for tensile peak amplification, threaded-connection failure, and packer mandrel damage. This study establishes a relatively complete analytical framework from load evolution and dynamic response to failure-risk identification, providing a theoretical basis for tubing-string integrity evaluation throughout the entire perforation process. -
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