Identification and treatment of severe MIC problems at a Gas Production Facility

Abstract

Identification and Treatment of Severe MIC Problems at a Gas Production Facility

Microbiologically influenced corrosion (MIC) is estimated to be responsible for billions of dollars of damage annually to oil and gas facilities worldwide. Microorganisms associated with MIC were detected in a major gas production plant at levels that represented a serious threat to the future integrity of the facility. In order to ascertain the root cause of the problem, a full physico-chemical and microbiological audit was conducted. Fluid and solid samples were taken throughout the system, from production wells, through the processing plant, to the produced water disposal wells. A suite of complimentary analytical techniques was used, including volatile fatty acid (VFA), total organic carbon (TOC), inductively coupled plasma mass spectrometry (ICP-MS) and molecular microbiology method (MMM) analyses. The results revealed a symbiotic relationship between sulphate-reducing bacteria, methanogens, Clostridia and Acetobacterium sp. that was thought to be causing the high microbial loading and severe MIC observed at this facility. Based on these results, a number of recommendations and changes to working practises and operational procedures were made, in order to secure the future integrity of this facility. This study highlights the importance of an integrated analytical approach, including both chemical and microbiological data, to fully understand and resolve MIC issues.