| During the process of CBM mining,due to corrosion,many underground faults will be caused,which will seriously affect the continuity of CBM production,an increase of material costs and construction costs,to bring huge economic losses in the production of CBM.Based on the corrosion of coalbed methane wells in H Block of Qinshui Basin,Firstly,analyszing the physical and chemical properties of formation water and composition of CBM,clearing the influencing factors of rod and tube corrosion.Secondly,the experimental materials used on-site steel,effects of different corrosion factors on the corrosion rate of rod and tube in the laboratory by weight-loss method,Thirdly,then through the computer simulation to verify the feasibility of the bio-geography optimization algorithm to optimize the BP neural network prediction of the corrosion rate.Finally,according to the three kinds of corrosion protection measures widely used in coalbed methane and Puting forward the most suitable anticorrosion technology(1)The research results on CBM wells in H Block show that the main factors of environmental corrosion in H Block include chloride ion,acid-base,temperature,pulverized coal concentration,pulverized coal particle size,oxygen partial pressure,partial pressure of carbon dioxide and partial pressure of hydrogen sulfide.(2)Indoor corrosion experiments showed that:1)the corrosion rate of the rod and tube increased with the temperature at 50 ℃;2)Under the experimental conditions,the corrosion rate of the rod and tube decreased with the increase of pH value;3)The higher the concentration of the chloride ion,the stronger the corrosion ability to the rod and tube;4)The higher the concentration of the pulverized coal,the higher the corrosion degree of the sample;5)The higher the size of the pulverized coal,the higher the corrosion rate;6)Different The corrosion rate of the pulverized coal is greater than that of single particle pulverized coal;7)The corrosion rate increases with the increase of oxygen partial pressure;8)The increase of carbon dioxide concentration will accelerate the corrosion rate of the rod and tube;9)The corrosion rate increases in a positive proportion with the increase of the partial pressure of hydrogen sulfide.(3)Corrosion prediction results show that the bio-geographical optimization algorithm can optimize the BP neural network to predict the corrosion rate in the H block.Compared with the traditional BP neural network prediction,the bio-geographical optimization algorithm improves the convergence speed and stability.According to the results of simulation diagnosis,the error of BBO-BP prediction is 2.63%lower than that of BP prediction result,which shows that bio-geography BP neural network has a good diagnosis effect and improves the accuracy of corrosion prediction.(4)Four kinds of anticorrosion techniques used in H coalbed gas wells(injecting corrosion inhibitor technology,cathodic protection technology,sucker rod anticorrosion technology and oil tube lining technology)are used.Through research and analysis,it is believed that the sucker rod anticorrosion technology and the pipe lining technology can be popularized,and the injection corrosion inhibitor and the cathodic protection technology should be used conditionally. |
