M. Yadav

Corrosion Inhibition of Tubing Steel during Acidization of Oil and Gas Wells

Acidization is an oil reservoir stimulation technique for increasing oil well productivity. Hydrochloric acid is used in oil and gas production to stimulate the formation. The acid treatment occurs through N80 steel tubes. The process requires a high degree of corrosion inhibition of tubing material (N80 steel). In the present investigation effect of synthesized amino acid compounds, namely, acetamidoleucine (AAL) and benzamidoleucine (BAL) as corrosion inhibitors for N80 steel in 15% HCl solution was studied by polarization, AC impedance (EIS), and weight loss measurements. It was found that both the inhibitors were effective inhibitors and their inhibition efficiency was significantly increased with increasing concentration of inhibitors. Polarization curves revealed that the studied inhibitors represent mixed type inhibitors. AC impedance studies revealed that charge transfer resistance increases and double layer capacitance decreases in presence of inhibitors. Adsorption of inhibitors at the surface of N80 steel was found to obey Langmuir isotherm.

Development of Ecofriendly Corrosion Inhibitors for Application in Acidization of Petroleum Oil Well

In the present investigation the protective ability of 1-(2-aminoethyl)-2-octadecylimidazoline (AEODI) and 1-(2-octadecylamidoethyl)-2-octadecylimidazoline (ODAEODI) as corrosion inhibitors for N80 steel in 15% hydrochloric acid has been studied, which may find application as ecofriendly corrosion inhibitors in acidizing processes in petroleum industry. Different concentration of synthesized inhibitors AEODI and ODAEODI was added to test solution (15% HCl), and corrosion inhibition of N80 steel was tested by weight loss, potentiodynamic polarization, and AC impedance measurements. Influence of temperature (298 to 323 K) on the inhibition behaviour was studied. Surface studies were performed by using SEM. It was found that both the inhibitors were effective inhibitors, and their inhibition efficiency was significantly increased with increasing their concentration. Polarization curves revealed that the used inhibitors represent mixed-type inhibitors. The adsorption of used inhibitors led to a reduction in the double-layer capacitance and an increase in the charge transfer resistance. The adsorption of used compounds was found to obey Langmuir isotherm. The adsorption of the corrosion inhibitors at the surface of N80 steel is the root cause of corrosion inhibition.

EXPERIMENTAL AND QUANTUM STUDIES ON ADSORPTION AND CORROSION INHIBITION EFFECT OF IMIDAZOLE DERIVATIVES ON N80 STEEL IN HYDROCHLORIC ACID

The inhibition effect of synthesized N′-(phenylmethylidene)-2-(2-methyl-1H-benzimidazol-1-yl)acetohydrazides, N′-(4-methylphenylmethylidene)-2-(2-methyl-1H-benzimidazol-1-yl)acetohydrazides, and N′-(4-methoxyphenylmethylidene)-2-(2-methyl-1H-benzimidazol-1-yl)acetohydrazides on the corrosion behaviour of N80 steel in 15% hydrochloric acid solution was investigated using weight loss, potentiostatic polarization and electrochemical impedance spectroscopy methods. The inhibition efficiency increased as the concentration of the inhibitors was increased. The effect of temperature on corrosion inhibition was investigated by weight loss method and thermodynamic parameters were calculated. Potentiodynamic polarization measurements show that all the three studied inhibitors act as mixed inhibitor. The adsorption of inhibitors on N80 steel surface obeys Langmuir adsorption isotherm. The structure of inhibitors was optimized using semiemperical AM1 method. Theoretical parameters such as the highest occupied molecular orbital (EHOMO), lowest unoccupied molecular orbital (ELUMO) energy levels, energy gap (ΔE = ELUMO - EHOMO), dipole moment (μ), global hardness (γ), softness (σ), binding energy, molecular surface area and the fraction of electrons transferred (ΔN) were calculated and the adsorption mechanism was discussed. Scanning electron microscopy was used to characterize the surface marphology of the N80 steel.

Inhibition Effect of Substituted Thiadiazoles on Corrosion Activity of N80 Steel in HCl Solution

The inhibition effect of some prepared compounds, namely, thiadiazole derivatives, on N80 steel corrosion in 15% HCl solutions has been studied by using the weight loss, electrochemical polarization, and electrochemical impedance spectroscopy techniques. It was found that the inhibition efficiency of the thiadiazole derivatives, namely, 2-amino-5-(4-methoxyphenyl)-1,3,4-thiazole (AMPT), 2-amino-5-phenyl-1,3,4-thiazole (APT), and 2-amino-5-(4-chlorophenyl)-1,3,4-thiazole (ACPT), increases with the increase in concentration. Inhibition efficiency follows the order AMPT > APT > ACPT. The effect of temperature on the corrosion was investigated by the weight loss method, and some thermodynamic parameters were calculated. The inhibitive action may be attributed to the adsorption of inhibitor molecules on the active sites of the metal surface following Langmuir adsorption isotherm. Polarization measurements indicated that thiadiazole derivatives act as mixed-type corrosion inhibitor. The adsorption of thiadiazole derivatives on N80 surface exposed to inhibitor-containing solutions was confirmed using SEM and FT-IR spectra.

Synthesis, Characterization, and Biological Activity of Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) Complexes of N-Thiophenoyl-N′-Phenylthiocarbohydrazide

Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) complex of N-thiophenoyl -N′-phenylthiocarbohydrazide (H2 TPTH) have been synthesized and characterized by elemental analysis, magnetic susceptibility measurements, infrared, NMR, electronic, and ESR spectral studies. The complexes were found to have compositions [Mn(H TPTH)2], [Co(TPTH) (H2O)2], [Ni(TPTH) (H2O)2], [Cu(TPTH)], [Zn(H TPTH)], [Cd(H TPTH)2], and [Fe(H TPTH)2(EtOH)]. The magnetic and electronic spectral studies suggest square planar geometry for [Cu(TPTH)], tetrahedral geometry for [Zn(TPTH)] and [Cd(H TPTH)2], and octahedral geometry for rest of the complexes. The infrared spectral studies of the 1 : 1 deprotonated complexes suggest bonding through enolic oxygen, thiolato sulfur, and both the hydrazinic nitrogens. Thus, H2TPTH acts as a binegative tetradentate ligand. H2 TPTH and its metal complexes have been screened against several bacteria and fungi.