Original scientific paper
Corrosion inhibition of oil-well steel (N-80) in simulated hydrogen sulphide environment by ferrous gluconate and synthetic magnetite
M.K. Amosa
orcid.org/0000-0001-6246-6963
; Department of Chemical Engineering, Ahmadu Bello University, Zaria, Nigeria.
I.A. Mohammed
; Department of Chemical Engineering, Ahmadu Bello University, Zaria, Nigeria.
S.A. Yaro
; Department of Metallurgical and Materials Engineering, Ahmadu Bello University, Zaria, Nigeria.
A.O. Arinkoola
; Department of Chemical Engineering, Ladoke Akintola University of Technology, Ogbomoso, Nigeria.
O.O. Ogunleye
; Department of Chemical Engineering, Ladoke Akintola University of Technology, Ogbomoso, Nigeria.
Abstract
Selected environmentally benign iron compounds (synthetic magnetite and ferrous gluconate) have been evaluated as corrosion inhibitors for oil-well steel (N-80) in 50 mg/l sulphide concentration at various pH ranging from 5.5 to 11.5 and at High Temperature, High Pressure (HTHP) conditions by the weight loss method. The test temperatures were 150 °F, 275 °F and 350 °F respectively for pressures of 3 000 psi, 5 000 psi and 6 000 psi. The ferrous complex was found to be a better corrosion inhibitor compared to the synthetic magnetite. It exhibited up to 99.2% inhibition efficiency (IE) when the dose of the scavenger was doubled (i.e. when the sulphide to scavenger ratio was 1:2) irrespective of other factors such as pH, temperature and pressure. Whereas, the synthetic magnetite’s optimum inhibition efficiency (IE) was observed to be up to 75.1% only when the ratio of the sulphide to scavenger was 1:4 at the lowest pH of the experiment (pH 5.5) which is not desirable for a drilling mud. As the pH increases, the inhibition efficiency of the magnetite decreases and found to be lowest at the alkaline pH of 11.5.
Keywords
corrosion inhibition; drilling fluid; environmental-benign; ferrous gluconate; oil-well steel, sulphides; synthetic magnetite
Hrčak ID:
53918
URI
Publication date:
31.5.2010.
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