Study On Space-time Distribution Characteristics Of Seepage Field And The Design Parameter Of Artificial Water Curtain For Underground Unlined Oil Storage Caverns

During construction seepage field redistribution and control is one of the key technical problems that underground oil storage rock caverns face.The water curtain and rock seepage control is an effective measure to control the groundwater.The proper and reasonabe water curtain and rock seepage control measures are the basis for the security construction and operations of a water seal oil caverns.In this article,the distribution characteristics of seepage field,the setting conditions of artifieial water curtain,the relevant design parameters and control standards are fully studied and analyzed by means of theoretical and numerical methods.The main research results are given as following:?1?A variety of factors such as the initial groundwater level distribution patterns,rock permeability and rainfall and evaporation have been considered to research the effect on the change process and characteristics of the seepage field and underground water around underground oil storage caverns by using single cavern and multi-cavern model.The effect of water sealing is evaluated and have obtained the relationship among the water cap thickness above caverns,the permeability coefficient and design groundwater level.?2?Based on the hydrogeologic conditions of a project of underground unlined oil storagecaverns,theunsteadyseepagefieldissimulatedandanalyzedby saturated-unsaturated seepage theory.It shows whether artifieial water curtain is necessary to be built the key index is the embedded depth of underground caverns and the surrounding rock permeability coefficient.When the surrounding rock permeability coefficient is large,the embedded depth of has a little influence on the distribution of the groundwater level.In addition,if the embedded depth of underground caverns increase slightly and the surrounding rock permeability coefficient is not enough small,the water seal condition of underground caverns coefficient will not be improved obviously.?3?The change characteristics of the seepage field and the water cap thickness above caverns are studied and the setting conditions and the necessary criteria of artifieial water curtain based on the rock permeability coefficient are proposed.When the distance from the design water level to the top of underground caverns is less than 80m and the surrounding rock permeability coefficient is greater than 0.5×10^-3m/d,the artifieial water curtain must be set up.Otherwise,when the caverns depth is large enough,the artifieial water curtain is no longer necessary.If the surrounding rock permeability coefficient is very small,the caverns depth also can be appropriately reduced.?4?Some key parameters such as the water curtain design height and the water curtain hole spacing that have influence on water seal condition are optimized and analyzed.The relationship between the injected water pressure and the water curtain design height is achieved and some related suggestions are put forward.