Study On Corrosion Causes And Protection Measures Of Oil Gathering System In Songfangtun Oilfield

With the further exploitation of oil field,accidents caused by corrosion in oil field gathering and transportation system occur frequently.It is necessary to further explore the causes and protective measures of corrosion in oil field gathering and transportation system.Therefore,the corrosion situation of pipelines and equipment in Songfangtun oil field will be explored.Laboratory and field experiments will be carried out to study the causes and protective measures of Songfangtun oil field oil gathering system.According to the characteristics of oil well produced fluid in Songfangtun Oilfield,the composition characteristics are analyzed: the sulfide,water salinity,dissolved oxygen and bacteria content are determined,and the corrosion products of failure pipeline are analyzed by scanning electron microscope,and the medium factors causing internal corrosion of oil gathering system in Songfangtun Oilfield are found.Indoor dynamic corrosion experiment equipment was established and indoor corrosion experiment was carried out.The influence of different corrosion factors on gathering and transportation system was studied by weight loss method.The relationship between different water content,temperature,flow rate,material and corrosion rate was explored,and the corrosion law of oil gathering system was summarized.To carry out on-site corrosion law test in oil field,the corrosion hanging pieces were placed inside the three-in-one and two-in-one storage tanks for research,and the corrosion law of storage tanks was explored.Carry out the optimization experiment of corrosion inhibitor dosage: carry out the indoor experiment of different concentration of corrosion hanging pieces by using the corrosion inhibitor provided in the field,and optimize the dosage of corrosion inhibitor.Three kinds of hanging pieces were selected for indoor corrosion test to analyze the anti-corrosion performance of different pipes.The results show that the sulfide concentration increases with the increase of water content.The content of bacteria,especially sulfate reducing bacteria,increased with the increase of water content.Corrosion on the inner wall of the failure section belongs to the aggregation of ferric oxide,iron sulfide,carbonate scale and aluminosilicate.The corrosion rate of carbon steel increases with the increase of temperature in the temperature range of30?~80?.In the range of 0.2m/s ~ 2.2m/s,the corrosion rate of carbon steel increases first and then decreases with the increase of medium flow rate.The mass concentration of corrosion inhibitor added on site should be controlled in the range of 15 mg/L to 20 mg/L in order to achieve the anticipated anticorrosive effect.