A Study On The Corrosion Mechanism Of Gas Well Shaft In Yang Chang Exploration Area

At present,with the prolongation of the development time,the gas wells in the Yangchang exploration area,the water production of gas wells increases year by year.Because of the high CO₂ and H₂S in natural gas and the high salinity of water medium,the wellbore corrosion of producing gas wells is becoming more and more serious.Well bore corrosion perforation and corrosion break off frequently,resulting in gas field production can not be carried out normally,seriously restricting the development and utilization of natural gas wells.On the other hand,the wellbore of gas well is the flow channel of oil and gas in the process of production.In the process of gas production,the wellbore of gas well is completely exposed to bad corrosion environment,and the wellbore of gas well is strongly corroded by acid gas under high temperature and high pressure.These corrosion can cause the casing of the wellbore of the gas well.Pitting corrosion or uniform corrosion,even the phenomenon of wellbore cracking caused a major accident.Therefore,it is very necessary to study the wellbore corrosion mechanism of natural gas wells and has great economic benefits.Based on the investigation and analysis of gas field production,development and corrosion status in Yanchang exploration area,the production data and reservoir characteristics of gas wells in Yanchang exploration area are collected,including formation division table,water sample analysis of gas well production,gas sample analysis,and so on.Pressure,temperature,etc;The investigation and analysis of gas well media with different gas-liquid ratio,different production and different properties in the representative well area Yan 2-Yan128 well area and Yan 145 well area are carried out and the correlation investigation of gas well production parameters is carried out.Simulating the corrosion of wellbore materials by different media under different conditions in a high temperature and high pressure reactor in the laboratory,and summarizing the gas well corrosion under different CO₂ conditions the corrosion law of wellbore casing in gas well under the conditions of content,temperature,velocity of flow,CI^-,HCO₃^-,H₂S,the composition analysis of corrosion products in corrosion test and the observation of corrosion morphology,the corrosion factors and corrosion mechanism of gas well are summarized.The final goal is to carry out a large number of laboratory simulation experiments on the medium of natural gas wells,accurately evaluate the corrosion characteristics of the medium of natural gas wells under various conditions,and develop and effectively evaluate a new corrosion control technology with strong adaptability and good effect.