Macro and microbiological growth can have significant impacts on safe and efficient operations, particularly in water injection and oil production systems, and in any locations where minor amounts of water may be present (e.g. diesel storage), in drilling and completion fluids, and in potable water systems. This growth usually causes problems such as reservoir souring, blocked pipelines, injectivity decline and loss due to formation plugging, corrosion of steel (MIC), disintegration of concrete or the production of toxic and corrosive hydrogen sulphide (H2S) gas.
Reservoir souring is a process in which a previously sweet oilfield (i.e. one which contains no H2S) begins to produce fluids containing H2S generated by microbiological activity. It typically occurs in reservoirs flooded by sea water for pressure maintenance or secondary oil recovery, as a result of the introduction of sulphate-rich water containing sulphate-reducing microorganisms into nutrient-rich formation water.
John Crane's team have been running a joint industry research project (JIP) for over twenty years into means of better predicting and controlling reservoir souring, including development of the world’s foremost reservoir souring predictive modelling tool, SourSim®RL.
Corrosion audit, control and mitigation
Corrosion is estimated to cost the oil and gas industry billions of dollars a year, in corrosion failures, repair costs, fines and shut downs. There have even been fatalities as a result of the sudden, unexpected failure of pipelines and process equipment. An important feature of any corrosion-related failure analysis is to determine why a specific event has occurred.
Our team utilizes the most appropriate technologies when monitoring corrosion in oilfield environments.
As part of understanding the cause and providing mitigation strategies for reservoir souring and corrosion, our team routinely carries out microbial surveys. This is done through a combination of on-site and laboratory analysis using both conventional and the latest molecular microbiological monitoring (MMM) techniques.
Studies include, bacterial enumeration using most probable number (MPN) growth media, polymerase chain reaction (PCR), quantitative polymerase chain reaction (qPCR), denaturing gradient gel electrophoresis (DGGE), next generation sequencing (NGS) of 16S rRNA genes, advanced 3D-microscopy of corrosion coupons.