司想,张宝,景宏涛,彭建云,唐佳鑫,韩国庆. 间歇生产气井关井续流阶段井筒内流体状态气液劈分模拟方法[J]. 石油钻采工艺,2023,45(6):720-728,737. DOI: 10.13639/j.odpt.202311014
引用本文: 司想,张宝,景宏涛,彭建云,唐佳鑫,韩国庆. 间歇生产气井关井续流阶段井筒内流体状态气液劈分模拟方法[J]. 石油钻采工艺,2023,45(6):720-728,737. DOI: 10.13639/j.odpt.202311014
SI Xiang, ZHANG Bao, JING Hongtao, PENG Jianyun, TANG Jiaxin, HAN Guoqing. A simulation method for gas-liquid splitting of fluid state in the well during the shutdown and continuous flow stage of intermittent production gas wells[J]. Oil Drilling & Production Technology, 2023, 45(6): 720-728, 737. DOI: 10.13639/j.odpt.202311014
Citation: SI Xiang, ZHANG Bao, JING Hongtao, PENG Jianyun, TANG Jiaxin, HAN Guoqing. A simulation method for gas-liquid splitting of fluid state in the well during the shutdown and continuous flow stage of intermittent production gas wells[J]. Oil Drilling & Production Technology, 2023, 45(6): 720-728, 737. DOI: 10.13639/j.odpt.202311014

间歇生产气井关井续流阶段井筒内流体状态气液劈分模拟方法

A simulation method for gas-liquid splitting of fluid state in the well during the shutdown and continuous flow stage of intermittent production gas wells

  • 摘要: 间歇生产井大部分无封隔器,从储层产出的气水存在气液量劈分以及油管、环空内液面高度随关井时间变化等问题。常规处理办法是通过简单假设气液在管鞋处的油套管流向来确定关井阶段油套管液面变化,会产生较大的误差。采用离散井筒模型,考虑零液流两相流动规律和油套管压力平衡,建立天然气井间歇生产气液劈分模型。利用该模型可以获取气泡在零液流液柱流动过程中的压力分布、流型变化、液柱高度波动、气泡流速等关键参数。同时,搭建全尺寸井筒实验装置模拟间歇生产井关井阶段气泡上升过程,通过摄影机观察零液流液柱中流型分布,测量液柱中气泡速度和压力。研究结果表明,气泡在零液流液柱中主要分布形式是分散气泡和泰勒泡,随着气体流速增大,泰勒泡流动占主导因素。根据实验结果对所建立的模型中流体压力、流型变化和气泡速度进行验证,准确率超过95%。该模型可精确描述间歇生产气井关井续流阶段气液流动规律和压力分布。

     

    Abstract: In intermittent production wells, most of which are free of packers, such issues as the gas-liquid production splitting and the changes in liquid levels in annulus space and tubing with shut-in duration occur. The conventional responding measures determine the liquid level changes in the tubing and casing during the shut-in stage by simply assuming the flow direction of the gas and liquid in the tubing and casing at the shoe, which will introduce significant errors. By employing a discrete wellbore model, considering zero-liquid-flow two-phase flow dynamics and pressure equilibrium in the tubing and casing, a gas-liquid splitting model for intermittent gas wells was established. The model allows for the determination of critical parameters, such as pressure distribution, flow pattern changes, fluctuation in liquid column heights and bubble velocities during the zero-liquid-flow liquid column movement. Additionally, a full-scale wellbore experimental setup was constructed to simulate the ascent of bubbles during shut-in periods in intermittent production wells. By using high-speed cameras, the flow pattern distribution in zero-liquid-flow liquid column was captured, and the velocities and pressures of the bubbles in the liquid column were measured. The research results show that bubbles in the zero-liquid-flow liquid column exhibit dispersed and Taylor bubble forms, with Taylor bubbles becoming dominant as gas flow rates increase. The fluid pressures, flow pattern changes and bubble velocities in the established model were verified based on the experimental results, with an accuracy of over 95%. This model can accurately describe the gas-liquid flow pattern and pressure distribution during after flow stage for intermittent gas production wells.

     

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