Halophilic Plant Extracts as Natural Corrosion Inhibitors and Biocides for Oil Field Application

Abstract:
Microbiologically influenced corrosion (MIC) is an umbrella term for a range of mechanisms in which bacteria use elemental metals as part of their primary or secondary metabolism, thus degrading the structural integrity of the metal over time. Estimates vary, but the consensus is that over 40% of corrosion-related maintenance costs in the oil and gas industry are caused by MIC and reservoir souring.

Seawater is often pumped into oil fields to keep up the pressure during secondary oil recovery. A negative side effect of this is the addition of sulfate, which is naturally present in seawater in substantial amounts.
Many of the bacteria that have been linked to MIC are sulfate-reducing organisms, sulfate-reducing bacteria, or -archaea (SRB and SRA, respectively), with the main focus in literature being on SRB. Currently, MIC is dealt with in two ways: Chemically with biocides and physical removal.

Halophytes are plant species that grow irrigated by seawater. These plants have been shown to produce a wide variety of very active phytochemicals, including potent antimicrobials. Extracts from some of these plants have proved to be inhibiting drug-resistant bacteria like E. coli and K. pneumoniae and fungi such as A. niger.

During the project, halophyte extracts will be produced using various extraction methods to find the optimal conditions. Bactericidal efficacy experiments will mainly be carried out in experimental setups inoculated with bacteria from the oil industry. Screenings will be carried out using serum bottles. These bottles are ideal for screening many parameters due to their small size, gas-tight nature, and ease of sampling. Verification experiments will be carried out using CDC Biofilm Reactors which can be run as either BSTR or CSTR providing constant shear stress over a biofilm surface.

Funding: DHRTC (The Danish Hydrocarbon Research and Technology Centre)