Synthesis Of Corrosion Inhibitor Used For Oil And Gas Field And Study Their Compound Performance

With the development of oil and gas fields and the improvement of oilproduction technology, serious corrosion problem is found in tubing andtransportation pipelines exposed to O₂, CO₂, H₂S/CO₂and high salinityformation water,which hinder the development of oil and gas industry. In thispaper, inhibitors were synthesized and their compound performances wereinvestigated in the simulated oil and gas field corrosive environment.In O₂/CO₂corrosive environment, a kind of amide corrosion inhibitorBMIA was synthesized and its compound performance with hydrazine, adeoxidant, was studied by dynamic weight loss method. The results revealedthat the best ratio of amide corrosion inhibitor BMIA to hydrazine is2:3.According to the ratio, finally we gain a new corrosion inhibitor BMIA-H.When the concentration of BMIA-H is500mg/L, the inhibition efficiency canreach98.32%; the polarization curve measurement revealed that BMIA-H is amixed-type corrosion inhibitor; Adsorption of the amide corrosion inhibitorBMIA on steel surface obeys Langmuir adsorption isotherm and belongs to achemical adsorption.In CO₂corrosive environment, an imidazoline quaternary ammonium salt BMI was synthesized with oleic acid, diethylenetriamine and diethylsulfate and its compound performance with surfactants and thiourea wasstudied by static weight loss method. The results revealed that the bestcomposition is25%BMI-1+3%thiourea+12.5%OP-15.When concentration ofcompound corrosion inhibitor is50mg/L, the corrosion rate of Q235steel is0.031mm/a and the efficiency can reach85%; The polarization curvemeasurement revealed that BMI is a mixed-type corrosion inhibitor whichmainly inhibits the anodic process of corrosion. Meanwhile, the optimalsynthesis process for quaternary ammonium salt BMI-1is as following: thereaction temperature is within50℃～60℃; reaction time is3h; the ratio is1:0.8.In H₂S/CO₂corrosive environment, the compound performance ofpyridine corrosion inhibitor PB-1with other reagents was studied. The resultsrevealed that PB-1and surfactant AEO-20show synergistic effect. But PB-1and gemini surfactant12-n-12or the mercaptoethanol show antagonistic effect;When the content of surfactant AEO-20is10%, a compound pyridineinhibitor PB-1c was gained whose inhibition performance is better than twoindustrial inhibitors BHH-15and114with dynamic weight loss method; Thepolarization curve measurement revealed that compound inhibitor PB-1c is ananodic type inhibitor.