Biocide-mediated corrosion of coiled tubing

Abstract

Coiled tubing corrosion was investigated for 16 field water samples (S5 to S20) from a Canadian shale gas field. Weight loss corrosion rates of carbon steel beads incubated with these field water samples averaged 0.2 mm/yr, but injection water sample S19 had 1.25±0.07 mm/yr. S19 had a most probable number of zero acid-producing bacteria and incubation of S19 with carbon steel beads or coupons did not lead to big changes in microbial community composition. In contrast other field water samples had most probable numbers of APB of 102/mL to 107/mL and incubation of these field water samples with carbon steel beads or coupons often gave large changes in microbial community composition. HPLC analysis indicated that all field water samples had elevated concentrations of bromide (average 1.6 mM), which may be derived from bronopol, which was used as a biocide. S19 had the highest bromide concentration (4.2 mM) and was the only water sample with a high concentration of active bronopol (13.8 mM, 2760 ppm). Corrosion rates increased linearly with bronopol concentration, as determined by weight loss of carbon steel beads, for experiments with S19, with filtered S19 and with bronopol dissolved in defined medium. This indicated that the high corrosion rate found for S19 was due to its high bronopol concentration. The corrosion rate of coiled tubing coupons also increased linearly with bronopol concentration as determined by electrochemical methods. Profilometry measurements also showed formation of multiple pits on the surface of coiled tubing coupon with an average pit depth of 60 μm after 1 week of incubation with 1 mM bronopol. At the recommended dosage of 100 ppm the corrosiveness of bronopol towards carbon steel beads was modest (0.011 mm/yr). Higher concentrations, resulting if biocide is added repeatedly as commonly done in shale gas operations, are more corrosive and should be avoided. Overdosing may be avoided by assaying the presence of residual biocide by HPLC, rather than by assaying the presence of residual surviving bacteria.

Halophilic Methylotrophic Methanogens May Contribute to the High Ammonium Concentrations Found in Shale Oil and Shale Gas Reservoirs

“…The observation that passage of sample FBW6 through an 0.2 µm filter had little effect on the corrosion rate and that three separate measurements gave very similar results (0.44 ± 0.12 mm/year unfiltered, 0.55 ± 0.06 mm/year unfiltered, and 0.57 ± 0.02 mm/year filtered) indicates chemical corrosion. Similar studies on the corrosivity of Duvernay shale gas samples from another field implicated the biocide used in the high corrosion rate of 1.25 mm/year observed for one out of 16 samples (Sharma et al, 2017). In the present study we cannot comment on which chemical(s) may have been contributing to the observed high corrosion rates in some of the samples.…”

“…Reincubation of 5 BBs with FBW6, which was either used directly or was filtered using an 0.2 µm Millipore nylon membrane (VWR International, Edmonton, AB) gave general corrosion rates of 0.55 ± 0.06 and 0.57 ± 0.02 mm/year, respectively (data not shown). These results indicate that MIC may not be a major contributor to the high corrosion rates observed for some of these shale gas samples, chemical corrosion is more likely (Sharma et al, 2017).…”

Comparative Evaluation of Coated and Non-Coated Carbon Electrodes in a Microbial Fuel Cell for Treatment of Municipal Sludge

“…Fluorometry was used for quantification of DNA and PCR products. A two-step PCR process, as described in previous studies [37,38], followed, in which the first PCR step targeted the V6-V8 hypervariable region of the 16S rRNA gene, using 926Fi5 and 1392Ri7 primers. The second PCR protocol was done for 8 cycles, using the barcoded primers P5-S50X-OHAF and P7-N7XX-OHAF.…”

“…The second PCR protocol was done for 8 cycles, using the barcoded primers P5-S50X-OHAF and P7-N7XX-OHAF. The final DNA concentration of the second set of PCR products was normalized to 4 ng/µL, pooled, and sequenced using the Illumina MiSeq TM platform at the Alberta Children's Hospital Research Institute (Calgary, AB, Canada) [37,38]. The raw reads obtained from sequencing were processed using MetaAmp, an open-source amplicon analysis pipeline [39,40].…”

Optimization of Preservation Methods Allows Deeper Insights into Changes of Raw Milk Microbiota

“…Although these preservatives have a broad spectrum of activity against Gram-positive and Gram-negative bacteria, their impact on the abundance and diversity of raw milk microbiota is not well known. Previous investigation outcomes on their ability to preserve microbial populations based on culture-independent techniques, once only limited to a few species for DNA isolation and PCR assays [17], are now expanding to high-throughput sequencing of whole communities [9,[18][19][20]. However, few of these studies dealt with dairy milk, and none of them, to our knowledge, analyzed the temporal variations of viable microbial communities in refrigerated milk preserved with azidiol or bronopol, using high-throughput sequencing technologies.…”