Integrated Approach Toward Diagnosing Microbiologically Influenced Corrosion in the Petroleum Industry

Abstract

The microbiologically influenced-corrosion (MIC) -related problems encountered in the water-injection wells of the Rijn Oil Field, offshore the Netherlands, were assessed from multiple perspectives to determine the root cause of the corrosion and the declining injection performance. Various classical petroleum-engineering methods were combined with full-bore electromagnetic inspection and 3D laser scanning of tubing sections to analyze the injectivity and integrity problems on both well and reservoir scales. Quantitative evaluation of materials by scanning electron microscopy (QEMSCAN), a novel technique for quantitative analysis of minerals, was used to identify chemical components in the corrosion products and allowed us to reconstruct the electrochemical processes that had taken place on a micrometer scale. Molecular microbiological methods (MMMs) such as quantitative polymerase chain reaction (QPCR) and 16S next-generation sequencing (NGS) were applied to identify the entire microbial population in various samples. Petroleum engineering, corrosion engineering, and microbiology were thus combined in a multiscale and multidisciplinary approach. This approach was followed successfully during the diagnostic process, resulting in verifiable hypotheses about the fundamental corrosion and plugging mechanisms in these water-injection wells. The results confirmed that the dominant corrosion process was MIC. Also, the presence of chloride contributed significantly to the corrosion process, possibly in combination with underdeposit corrosion (UDC). The full suite of analyses shed light on possible causes of the declining injectivity in the wells: There appeared to be a link between the formation of deposits and corrosion, strongly influenced by microbes. In this paper we demonstrate the importance of an integrated approach, which can lead to reliable diagnostics and successful mitigation against future corrosion and the declining performance of wells and pipes.