Robertson, Allana Rae (2016-05). Real Time, Low Cost Technologies for Determining Treated Oil and Gas Produced Water Stability. Master's Thesis. Thesis uri icon

abstract

  • Microbial activity in raw repurposed waters from oil and gas operations is known to cause enhanced corrosion in flow lines and downhole fouling in the reservoir if left un-treated. For this reason, shale operators prefer to use biocides or mobile treatment units to treat raw production waters. Unfortunately, field experience has shown that biocide treatments alone are ineffective and costly. In addition to these findings, produced water stability during storage is not yet well documented due to difficulty in obtaining timely and accurate microbial levels. Concluding an extensive literature review, industry inquiry, and referencing three levels of scale up testing (laboratory, pilot, and field scales), water treatment studies identified three low cost, real time analysis technologies. Using the identified technologies, membrane filtration was evaluated as a technique to reduce microbial activity and primary microbial metabolites in raw produced waters. Filtration treatment does efficiently reduce biomass levels in produced water. Using a two-stage filtration scheme with micro and nano filtration membranes, a significant reduction of divalent ion species and of biological activity is observed in permeate waters. Monovalent species were not found to be directly affected by filtration treatment. Metabolically active monovalent ions including: nitrate, ammonia, ammonium and nitrite were found to be reduced by microbial activity in permeate during temporary storage. Additional metabolically active ions including: soluble iron, sulfate, manganese, and dissolved organic carbon were found to be reduced by filtration treatment. Their divalent nature and organic compound molecular weight are thought to be the source. Concluding the study, it was found that treated produced water still exhibits an unstable, nutrient rich nature capable of supporting microbial growth and oxidation-reduction activity during storage. Therefore, without the addition of a biocide to establish a residual concentration, microbial biomass levels can be expected to regrow. Current publications available to industry members primarily focus on identifying corrosion and the specific bacteria responsible. Little information is published on methods of treatment and quality control. In addition few "field ready" biological activity monitoring methods are available to the industry. Publishing this paper would provide information about testing technology and the specific metabolic species that must be monitored to ensure efficient microbial mitigation during treatment efforts.
  • Microbial activity in raw repurposed waters from oil and gas operations is known to cause enhanced corrosion in flow lines and downhole fouling in the reservoir if left un-treated. For this reason, shale operators prefer to use biocides or mobile treatment units to treat raw production waters. Unfortunately, field experience has shown that biocide treatments alone are ineffective and costly. In addition to these findings, produced water stability during storage is not yet well documented due to difficulty in obtaining timely and accurate microbial levels.

    Concluding an extensive literature review, industry inquiry, and referencing three levels of scale up testing (laboratory, pilot, and field scales), water treatment studies identified three low cost, real time analysis technologies. Using the identified technologies, membrane filtration was evaluated as a technique to reduce microbial activity and primary microbial metabolites in raw produced waters.

    Filtration treatment does efficiently reduce biomass levels in produced water. Using a two-stage filtration scheme with micro and nano filtration membranes, a significant reduction of divalent ion species and of biological activity is observed in permeate waters. Monovalent species were not found to be directly affected by filtration treatment. Metabolically active monovalent ions including: nitrate, ammonia, ammonium and nitrite were found to be reduced by microbial activity in permeate during temporary storage. Additional metabolically active ions including: soluble iron, sulfate, manganese, and dissolved organic carbon were found to be reduced by filtration treatment. Their divalent nature and organic compound molecular weight are thought to be the source. Concluding the study, it was found that treated produced water still exhibits an unstable, nutrient rich nature capable of supporting microbial growth and oxidation-reduction activity during storage. Therefore, without the addition of a biocide to establish a residual concentration, microbial biomass levels can be expected to regrow.

    Current publications available to industry members primarily focus on identifying corrosion and the specific bacteria responsible. Little information is published on methods of treatment and quality control. In addition few "field ready" biological activity monitoring methods are available to the industry. Publishing this paper would provide information about testing technology and the specific metabolic species that must be monitored to ensure efficient microbial mitigation during treatment efforts.

publication date

  • May 2016