储气库多周期注采条件下的管柱受力特征分析
Analysis of Stress Characteristics of Injection-Production String under Multi-Cycle Conditions in Gas Storage

地下储气库是天然气能源管理的高效手段，注采管柱在天然气调峰过程发挥着重要作用，在不同注采周期下注采管柱的受力状态有很大差异，不同的环空带压情况，又会引起管柱受力状态发生变化，会加速管柱损坏。因此，本文建立了考虑鼓胀效应、活塞效应、流体摩阻效应和温度效应的注采管柱力学分析模型，以某储气库为例，分析了不同环空压力、注采气时运行压力和不同封隔器位置下管柱受力和中性点位置的变化规律，且该管柱在井口、封隔器和悬挂器处轴向载荷突变较大，管柱中性点位置在965~1660 m之间变化，这使该区域管柱处于拉压交变的应力状态，容易引起管柱疲劳损坏和形成漏气点。该研究结果对储气库注采管柱漏气点监测、注采压力参数和封隔器安放位置优化设计有重要意义。
Underground gas storage is an efficient means of natural gas energy management, and the injection and production string plays an important role in the process of peak regulation of natural gas. The stress state of the string varies greatly in different injection and production cycles, and the stress of the pipe string will change under different annular pressure conditions, which makes the pipe string subject to cyclic and alternating loads for a long time, which will accelerate the damage of the pipe string. Therefore, a mechanical analysis model of injection-production string was established, which takes into account swelling effect, piston effect, fluid friction effect and temperature effect. A gas storage well was taken as an example to analyze the variation law of pipe force and neutral point position under different annulus pressure, operating pressure during gas injection and production, and different packer positions. In addition, the axial load of the string at the wellhead, packer and hanger changes greatly. The position of the neutral point of the string varies between 965 and 1660 m, which puts the string in the tension and pressure alternating stress state, which is easy to cause fatigue damage to the string and the gas leakage point. The research results are of great significance to the monitoring of gas leak point of injection-production string during gas storage process, the parameters design of the injection-production pressure and packer placement.