Force Analysis And Calculation Of Pipe String In High Temperature And High Pressure Gas Well

As energy demand increasing and extension of oil and gas exploratory development field,deep gas reservoirs has become an important alternative energy.Deep gas well has characteristics of high temperature and high pressure.The work environment of down hole string is very bad,string stress and deformation are also complex,which lead to accidents occur frequently,such as bottom string breaking and packer losing.It severely restricts safe and economical development of deep gas wells with high temperature and high pressure.The research of string mechanical behavior is urgently needed,which provides theoretical basis and technical support for construction parameter.Firstly,this paper based on wellbore fluid mass conservation,momentum conservation,energy conservation and wellbore heat transfer theory,considered effect of frictional heating and convection heat transfer,established a pressure and temperature transient forecast model and used double iteration method to solve it.Calculation of 4 gas wells indicates that predictive value have good agreement with the actual value and meet the oilfields requirements.Then a mathematical model of dual packer complex string is established in temperature effects,ballooning effect,piston effect and buckling effect.This article analyzed three-dimensional stress of the dangerous section column,gave the basic formula of column strength check.Besides,this paper established a mechanical model of downhole packer,calculated the plastic tube sealing deformation and mechanical properties of deformation process of institutional,studied the distribution of slips anchor packer sleeve contact stress between the institutions.Based on the above theoretical study,a high pressure and high pressure gas wells pipe string mechanical analysis was developed by C# and Matlab.Finally,the paper carried out stress analysis and safety evaluation on downhole pipe string of A well.