呼图壁地下储气库地表形变模式与机理研究

A Study on Pattern and Mechanism of Surface Deformation of Underground Gas Storage in Hutubi

为探究地下储气库区域地表形变时空分布特征及影响因素,利用Sentinel-1A升轨合成孔径雷达影像,基于小基线集雷达干涉测量(SBAS-InSAR)技术提取了2017年3月—2019年5月呼图壁地下储气库的时序地表形变信息。结果表明,在时间上,每年4月至10月注气阶段储气库地表靠近卫星约10~30 mm;同时,在夏季降水量不能满足农田灌溉需抽取地下水时,注气阶段储气库区域特别是接近农田灌溉井的区域由于抽取地下水会存在明显的抬升量减小现象;每年11月至次年3月的采气阶段,地表远离卫星约5~10 mm。空间上,储气库西侧卫星视线向抬升大于东侧,注气时地表抬升响应也较为迅速;而离灌溉井近区域地表抬升量明显减小。分析发现储气库注气阶段地表抬升,采气阶段地表沉降;区域存在地下水抽取时导致地表抬升量有减小趋势,储气库区域地表形变是注采气与地下水抽取综合作用的结果。

In order to explore the spatial distribution characteristics and influencing factors of the surface deformation of Hutubi underground gas storage by monitoring its surface deformation information.Using Sentinel-1 A ascending orbit synthetic aperture radar data and based on small baseline subsets radar interferometry(SBAS-InSAR) technology,the time series surface deformation information of Hutubi underground gas storage during March 2017 to May 2019 is obtained.It turns out that in terms of time,from April to October every year,the surface of gas storage is about 10~30 mm close to the line of sight of the satellite at the gas injection stage;at the same time,when the summer rainfall cannot meet the requirement of farmland water supply and groundwater needs to be pumped for irrigation,the gas storage area,especially the area close to farmland irrigation wells,has a obvious decrease in uplift phenomenon due to the pumping of groundwater during the gas injection period.During the gas production stage from November to March of the following year,the extraction of gas causes the surface of the gas storage to be 5~10 mm away from the line of sight of the satellite.In space,the line of sight of the satellite on the west side of gas storage rises more than that on the east side,and the response of surface uplift is fast when gas is injected.At the same time,the area closer to the irrigation well will cause obvious decrease in uplift due to groundwater exploitation.It is found that the surface uplifted during gas injection and the surface subsided during gas production,and there is a tendency that decrease in surface uplift when the groundwater is extracted.The surface deformation in the gas storage area is the result of the combined effect of gas inj ection and groundwater extraction.