盐穴储气库水平腔形态稳定性优选

Optimal selection of shape stability for horizontal cavities in salt cavern gas storage

目前盐穴储气库主要采用单井垂直造腔方式建造,但对于薄盐层,该方法造腔体积小,盐层利用率低,并不适用。采用双井水平造腔方式可有效解决上述问题,而水平腔形态对腔体的稳定性和储气能力至关重要。为了优选出最佳形态,提出了一种水平腔形态优选方法。通过造腔物理模拟实验获得不同形态的水平腔模型,并采用逆向工程建模,利用FLAC3D软件进行静力学和恒压流变稳定性评价优选。实验结果显示,水平腔形态可分为4类,“驼峰”型、“一端大一端小”型、“两端大中间细长”型、“平顶”型;根据变形、塑性区分布、体积收缩率综合评价,“驼峰”型腔体稳定性明显好于其他形态腔体。因此,建议现场采用水平多步法造腔方式,设计建造“驼峰”型水平腔,可提高腔体稳定性和储气能力。

At present,salt cavern gas storages are mainly built in a vertical cavity pattern with single well,however,for thin salt layers,this method will lead to small cavity volume and low utilization rate of salt layers,which is unsuitable.The above-mentioned problem can be effectively solved by adopting horizontal cavity-built pattern with double wells,and the shape of the horizontal cavities is crucial to the stability and gas storage capacity.In order to optimally select the best shape,a method for optimally selecting the shape of the horizontal cavities was proposed.The horizontal cavity models with different morphologies were obtained through the physical simulation experiment,and then by modeling with reverse engineering,the statics and the constant-pressure rheological stability were evaluated and optimally selected with the help of the FLAC3D software.The results show that the shapes of the horizontal cavities can be divided into 4 types,this is,hump type,one end large and one end small type,both ends large and middle slender type,and flat top type.According to deformation,plastic zone distribution,and comprehensive evaluation of volume shrinkage rate,the stability of the hump cavity is significantly better than that of other shapes.Therefore,it is recommended to adopt a cavity-built pattern with horizontal multi-step method on site,and to design and build hump horizontal cavities,which can improve the cavity stability and gas storage capacity.