Synthesis And Application Of Corrosion Inhibitors For New High-efficiency Oilfield Water Injection System

With the continuous development of oilfield waterflooding technology.Corrosion problems of oilfield waterflooding systems have become increasingly prominent.In view of the corrosion status of oilfield water injection systems,corrosion inhibitors is the most simple and efficient method for protection.In this paper,rosin amido dopamine(SDX)was synthesized by rosin and dopamine.The single-factor experiments and the orthogonal test were used to obtain the optimal synthesis conditions.The results as follows:the molar ratio of raw material was 1:1.2,reaction temperature was 75? reaction time was 6 h,and the yield of rosin amido dopamine can reach 70.11%.The rosin imidazoline was synthesized by rosin and hydroxyethyl ethylenediamine.The optimal synthesis condition was selected by single-factor experiments and orthogonal test.The results as follows:the molar ratio of rosin to hydroxyethyl ethylenediamine was 1:1.2,the temperature was 160?,the amidation time was 4.5 h,the cyclization temperature was 230?,and the cyclization time was 6 h,the acid value of the product can reach 10.05.Water-soluble rosin imidazoline quaternary ammonium salt(SXM)was modified with benzyl chloride.The static weight loss method was used to evaluate the performance of the two synthesized products.Simulated mineralized water as a corrosive medium and SDX as the main agent,The influence of dispersant PPJO-25,thiourea,and HPAA content on the corrosion of N80 steel sheet was investigated.The results showed that there is a good synergy between the three Compounds.When the dosage of SDX-3 is 100 mg·L-1,the corrosion inhibition rate can reach 68%.For rosin imidazoline quaternary ammonium salt(SXM),it showed the better corrosion inhibition performance in an acidic corrosive medium,and the effect of other auxiliaries,such as PPJO-25,thiourea,HPAA on the corrosion rate was examined.The results showed that there is a certain synergy between the main agent and additives.When dosage of SXM-3 is 200 mg·L-1,the corrosion inhibition rate can reach 86%.Electrochemical impedance spectroscopy and polarization curve tests and thermodynamic adsorption curve fittings were used to evaluate the mechanism of the two water,cathodic corrosion was mainly suppressed in metals.The adsorption of the surface conformed to the Frumkin adsorption model.The reaction was exothermic and spontaneous.The calculation of its molecular structure confirmed the possibility of the adsorption of the inhibitor on the metal surface.For the SXM-3 corrosion inhibitor,the cathodic corrosion was mainly inhibited in the acid simulated mineralized water,and its adsorption on the metal surface conformed to the Langmuir adsorption model,there were only adsorption and desorption between the corrosion inhibitor and the metal surface.The reaction was an exothermic and spontaneous reaction.Scanning electron microscopy showed that with the addition of the corrosion inhibitor,the surface of the test piece was smooth,with no significant pitting or severe corrosion marks.The addition of the two corrosion inhibitors can effectively inhibit metal corrosion.