Study On Corrosion Inhibitor For High-temperature Acidification

Acidification is one of the most important stimulation treatments in oil & gas development, and corrosion inhibitor is an important acidizing additive. In view of the performance requirements of the corrosion inhibitor and the problems of the using products at present, such as agglomeration, poor dissolution, and bad anticorrosion properties and so on, Mannich series and quaternary ammonium salt series corrosion inhibitors for high temperature were studied. The basic formula and the proper synthesizing conditions of the two series were determined. The structure of the synthesized chemicals was inspected using infrared spectrometer, properties of corrosion inhibitor YSH-05 and JAY-01 had been studied and assessed using polarization curve method, scanning electron microscope, and classical weight loss method. Polarization curve method shows that the prepared corrosion inhibitor YSH-05 is a mixed mode corrosion inhibitor mainly repressing negative pole process and JAY-01 is a negative pole mode corrosion inhibitor, the adsorption of YSH-05 and JAY-01 fits Bockris-Swinkels adsorption isotherm on the iron and steel surface. The study with Scanning electron microscope demonstrates that corrosion usually appears at defective areas and develops along with etch mark direction. Temperature tolerance of the prepared corrosion inhibitor is as high as 150℃. The results from laboratory experiments and the oilfield implementations indicate that excellent inhibitive efficiency of the products can be obtained at 130～135℃, and the inhibitive ability of YSH-05 is better than that of JAY-01. The products are characterized with steady properties, good dissolution ability and superior inhibition of corrosion, which can satisfy the requirements of acidification at high temperature. At present, the products are being widely used in western oilfields in China.