Scale deposition and corrosion are the two costliest
problems in the oil industry. During the inspection and maintenance carried out
in onshore wells in oil and gas production, the presence of adherent scales
inside the pipes was revealed. The oil, natural gas and formation water
produced in these onshore oil wells come from reservoir rocks rich in minerals
such as calcite (CaCO3) and/or dolomite (CaCO3.MgCO3). The formation waters of
these wells contain sufficient levels of Ca2+, Mg2+ and HCO3- ions to generate
carbonate scale, causing restrictions on the flow of oil and gas production. To
return to the initial conditions of oil production, it is necessary to remove
the internal carbonate scales with hydrochloric acid injection and to prevent
internal corrosion of carbon steel pipes, it is essential to add the corrosion
inhibitor to the acid solution. The present study evaluates the dissolution of
carbonate scale and the corrosion resistance of carbon steel using gravimetric
(mass loss) and electrochemical (polarization) tests. Studies were completed
with and without the addition of 250, 500 and 1,000 mg/L propargyl alcohol in
HCl solutions with concentrations of 10 wt. % and 15% wt. % at temperatures of
25, 40 and 60 °C. Chemical analyses have revealed that carbonate scales are
predominantly composed of 83% calcite, 2% dolomite and 2% kaolinite and the
rest is made up of iron oxides and hydroxides. The hydrochloric acid solutions
with 10 wt. % and 15 wt. % have become an excellent removing agent with a yield
of more than 98%. The results of mass loss assays showed that the addition of
propargyl alcohol in 10 wt. % and 15 wt. % HCl provided excellent protection to
the carbon steel with an efficiency superior of 95%.
Author(s) Details
Fernando B. Mainier
Universidade Federal Fluminense, Niterói, Rio de Janeiro,
Brazil.
Renata Jogaib Mainier
Universo – Universidade Salgado de Oliveira, S. Gonçalo, Rio
de Janeiro, Brazil.
Please see the book here:- https://doi.org/10.9734/bpi/cmsdi/v4/1053
