高温高压深井多封隔器分段改造管柱优化设计

Design Optimization of Multistage Stimulation String with Multi-packer for High Temperature and High Pressure Deep Well

针对水平井多封隔器高强度分段改造作业引起的管柱失效事故频发问题,充分考虑多封隔器分段改造井油管内流动和井筒传热特点,建立了井筒温压场精细预测数学模型;同时考虑封隔器间环空压力的各影响因素,建立了封隔器间环空压力瞬态预测数学模型,结合封隔器管柱强度校核理论,形成了一套多封隔器分段改造管柱设计方法。以一口高温高压深井为例,应用建立的设计方法开展了多封隔器分段改造管柱力学分析和优化设计,计算结果表明,井筒温压场的精细模拟和封隔器间环空压力的瞬态预测对多封隔器分段改造管柱设计至关重要。研究结果对多封隔器分段改造技术在高温高压深井中的推广应用提供了技术支撑。

In view of the frequent occurrence of pipe string failure caused by high-strength multistage stimulation with multi-packer in horizontal well, full consideration is given to the tubing fluid flow and wellbore heat transfer, and the fine prediction mathematical model of wellbore temperature and pressure field is established. Considering the influencing factors of the annulus pressure between the packers, the mathematical prediction model of the transient annulus pressure between packers is established. Combined with the packer and string stress check theory, a set of design method for multistage stimulation string with multi-packer is established. Taking a high temperature and high pressure deep well for case study, the pipe string mechanics analysis and design of multistage stimulation string with multi-packer are carried out using the established design method. The calculation results show that the precisely simulated wellbore temperature and pressure field and the transient pressure prediction of annulus between the packers are critical to the design of multistage stimulation string with multi-packer.