Corrosion hazards and inhibitor protection in the seawater injection system on the Baltic sea rig

• K. Domanska¹, P. Iglinski², J. Orlikowski³, K. Zakowski³ and K. Darowicki³

¹ Exploitation & Reservoir Engineering Department, LOTOS Petrobaltic Ltd, 9 Stary Dwor Street, 80-758 Gdansk, Poland
² Production Maintenance Division, LOTOS Petrobaltic Ltd, 9 Stary Dwor Street, 80-758 Gdansk, Poland
³ Department of Electrochemistry, Corrosion and Materials Engineering, Gdansk University of Technology, 11/12 Gabriela Narutowicza Street, 80-233 Gdansk, Poland

Abstract: Oil extraction efficiency in LOTOS Petrobaltic Company is increased by means of injection of seawater into an oilfield aquifer, which is implemented on the Baltic Beta rig, operating on the Baltic Sea. Operational experience has shown a significant degree of corrosion aggressiveness in the injected water, which necessitates frequent repairs of the seawater injection installation. Evaluation of the corrosion phenomena is crucial for rig platforms due to extremely high renovation costs and a negative impact on injected water quality. Chemical and microbiological analyses of seawater treated in the technological process have been carried out. Actions to estimate the corrosion risk in the installation and the estimated corrosion rates measured using an automated monitoring system are presented in this work. Monitoring of the corrosion rate conducted alongside measurements of the physicochemical properties of water allowed to identify the corrosion mechanisms of stainless steel in a seawater environment. Additionally, it became possible to assess the impact of the chlorine and carbon dioxide content on the corrosion rate, and to analyze the effectiveness of the corrosion inhibitor. The effectiveness of two types of commercial corrosion inhibitors has been estimated during different conditions.

Keywords: corrosion inhibitors, sea water injection system, linear polarization method, oil production

Int. J. Corros. Scale Inhib., 2020, 9, no. 3, 941-952 PDF (685 K)
doi: 10.17675/2305-6894-2020-9-3-9

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