Applied Research Of Inhibitor For Gathering Pipeline In Tarim Oilfield

Inhibitor is an important way to mitigate corrosion of oil and gas gathering pipeline. In this paper, inhibition mechanism and efficiency of 1-benzene propylene-N-(2-hydroxyethyl) ethylenediamine was investigated in CO2 containing formation water based on Tarim Oilfield used L360 line pipe in terms of weight loss and electrochemical results, influences of temperature, concentration, corrosion product film, and chemical additives on inhibitor were discussed.The weight loss results show that inhibition efficiency of 1-benzene propylene-N-(2-hydroxyethyl) ethylenediamine increased with the increasing of inhibitor concentration, inhibition efficiency decreased due to the desorption in elevated temperature. Electrochemical polarization results indicated that 1-benzene propylene-N-(2-hydroxyethyl) ethylenediamine is a mixed type inhibitor. 1-benzene propylene-N-(2-hydroxyethyl) ethylenediamine inhibitor adsorbs on L360 pipe steel in from of physical adsorption according to thermodynamics calculation.The in presence of corrosion product layer on L360 steel surface decreased the inhibition efficiency when low concentration 1-benzene propylene-N-(2-hydroxyethyl) ethylenediamine was added, while corrosion product layer has little effect on inhibition efficiency when high concentration of 150mg/L inhibitor was added. The bactericide and flocculant significantly increased the inhibition efficiency due to synergistic effect between inhibitor and bactericide/flocculant. Pre-filming of inhibitor can effectively protect L360 pipe steel from corrosion at early stage, enhanced corrosion was observed with the test continued, it is ascribed to that the inhibitor film was locally demaged on L360 pipe steel surface due to inhibitor molecules clustering, and one of the possible reasons is the critical micelle principle of molecular.