Stability Evaluation And Multi-factor Optimization Study Of Interbedded Salt Rock Gas Storage Period

As a storage facility for special logistics under the new environment,the underground gas storage tank can re-inject natural gas into the underground storage gas,and play the role of seasonal peaking,accident emergency gas supply and national strategic reserve.However,at present,China's gas storage capacity has a huge gap,which is far from enough to cope with the severe challenges of peaking and maintaining supply.Therefore,it is urgent to build more gas storage to meet the actual needs.The excellent characteristics of salt rock make salt rock an ideal storage medium.However,due to the particularity of domestic geology,plate tectonic movement and terrestrial sedimentary environment make China's salt rock deposits contain more impurities,especially in the geological zone.To deepen the difficulty of technical implementation,it is impossible to fully learn from the experience of foreign gas storage construction.There are many uncontrollable factors in the construction of cavity by water-soluble cavity.Therefore,this paper mainly studies the cavity construction period of interlayer salt rock gas storage.The research is mainly carried out from the following three aspects: perfecting the evaluation index system,establishing a mathematical model to evaluate the stability of the gas storage,and optimize the factors of the cavity construction process.The content is as follows:(1)Carry out theoretical research on stability of sandwich salt rock cavity.The stability of the cavity is studied from two angles,namely the dissolution characteristics of salt rock and interlayer during the cavity formation and the changes of mechanical properties during the dissolution process.The factors affecting the dissolution rate of salt rock,the dissolution rate under diffusion convection and the stress of interlayer were analyzed.The effects of the dissolution characteristics of the interlayer and the mechanical properties of the interlayer on the stability of the cavity were studied.(2)Establish a stability evaluation system for sandwich salt rock gas storage.On the basis of analyzing the instability phenomenon in the cavity period at home and abroad,the risk factors of the cavity period are summarized and summarized,and the index system is established by using the principle of horizontal longitudinal index selection.(3)Conduct gas storage safety evaluation.Establish unascertained measure-improved set pair analysis mathematical model to evaluate the safety of gas storage,compare the evaluation results,determine the stability development trend of the evaluation object,and find the key risk factors.(4)Perform a simulation of the factor optimization scheme.Analyze the key factors affecting the evaluation level of the case,design the orthogonal test plan,use the software to carry out the simulation analysis,select the optimization plan and substitute the established mathematical model for verification.Combining the examples to analyze the above content,it shows that the proposed method and software simulation have practical operation and engineering value,which can guide the actual work.A more comprehensive study of the life cycle of the gas storage can be carried out later.