Study Of Horizontal Well Solution Mining Cavity Expansion And Stability

The salt rock has excellent properties of low permeability,creep behavior,damage self-healing ability and solution mining.Therefore,underground salt cavern is the worldwide-recognized ideal reserve place of petroleum and gas.At the same time,in the use of solution mining to implement energy underground reserves has entered the stage of large-scale planning and construction.By 2020,the central and eastern regions will build 5 large salt cavity gas storage group,the total volume of more than 40 million cubic meters,and the third phase of national strategic oil reserve planning salt cave in 80 million tons of reserves.But our traditional single well water soluble technique of cavity making gas storage built in cavity volume and time have made cavity can't meet the increasing demand for salt cavity gas storage construction,this paper proposes using horizontal well water soluble made cavity technology for construction of the underground salt cavity gas storage.The main research content as the follows:(1)The salt mine geological characteristics and gypsum dissolution features.This paper expounds the main geological characteristics of salt mines in our country on the basis of conducting the salt rocks in different temperature,solution concentration and dissolution Angle under the condition of dissolution test,analyzes the corrosion law of formation.The study results in the solution parameters of the various factors,and the present situation of the dissolution of the salt rock in China is consistent with that of the foreign salt rock.(2)Aspects of cavity shape expansion of the horizontal well solution mining.According to the big flow and flow two situations corresponding laboratory flow,studies the two flow of horizontal well water soluble cavity forming regularity of cavity effect,and made cavity with single well water soluble,comparing the technology of cavity expansion reveals that the two kinds of technique of cavity making difference in cavity expansion.The research shows that the brine concentration increases with the building cavity and gradually stabilizes in the latter stages.Different water injection flow will affect the concentration of brine discharge and have no obvious effect on the regularity of cavity,large flow,the higher the concentration of the brine discharge in early,eventually get cavity volume.(3)Aspects of horizontal well salt cavity storage long-term stability.Set up several different levels in the shape of cavity and Flac3 D numerical simulation software is used to contrast analysis of the different shape level cavity volume,shrinkage cavity of peripheral convergence magnitude and distribution of plastic zone,find out the best level cavity shape stability,on the basis of the further optimization of shape of the cavity.In addition,the geological characteristics of salt rocks in China,the presence of intercalation salt cavity and the technology of different injection-production rate stability analysis for a long time,for our country in the shape of the horizontal well dissolved cavity design to provide technical guidance.Studies have shown that large horizontal lumens are more stable in the upper waist;The convergence of the short axis of the horizontal cavity is greater than that of the long axis.It can effectively improve the stability of the horizontal cavity during the period of operation.Under different cyclic pressure,there is little discernible effect on horizontal cavity stability.