Influence Of Crude Oil On Inhibition Performence Of Different Types Of Corrosion Inhibitors In H₂S/CO₂ Environment

H2S and CO2 extensively exist at the development and production process of oil and gas field. When those corrosive gases dissolve in high salinity brine, they will form the corrosive solution, which may cause severe damage to the oilfield equipment and pipeline.In the study of corrosion inhibitor used in the oil and gas field, it is usually only considered to use the simulation aqueous solution prepared in the laboratory to simulate the actual corrosive medium. However, in the actual process of oil exploration and transport, the multiphase flow made up of oil and water generally appears. Therefore, oil should be considered as an important factor to affect the corrosion-inhibition effect of corrosion inhibitors. In this thesis, the effect of oil on the water soluble type, oil soluble type and oil soluble water dispersible type corrosion inhibitors was mainly studied under the conditions of the laminar flow and turbulent flow system including water and oil in the high salinity H2S/CO2 corrosive medium. The main research contents and conclusions were as follows:(1) The corrosion process of carbon steel was simulated by the dynamic weightlessness. The average corrosion rate of 20# steel in this corrosive environment is 0.5000 mm/a. It could be inferred that the corrosion type of 20# steel was carbon dioxide corrosion and hydrogen sulfide corrosion from the results of SEM and EDS.(2) The corrosion performances of six corrosion inhibitors were evaluated by dynamic weight loss and electrochemical experiment. The order of inhibitive efficiency of six corrosion inhibitors was shown as follows:CI-15>OS-1>1A>WS-1>RD-1>OSWD-1.(3) The effect of oil on the water soluble, oil soluble and oil soluble water dispersible corrosion inhibitors was studied under the conditions of the laminar flow. The oil had the largest effect on the oil soluble type inhibitor making the corrosion rate increase greatly, while it had a slight effect on the water soluble type inhibitor. It had an obviously effect on the oil soluble water disperse type inhibitor too.(4) The effect of oil on the water soluble, oil soluble and oil soluble water dispersible corrosion inhibitors was studied under the conditions of the turbulent flow. The increase of oil content in the oil and water mixture could enhance the corrosion performance of corrosion inhibitors. However, the corrosion performances of oil soluble and oil soluble water dispersible corrosion inhibitors in the aqueous solution were better than in the oil and water mixture.