Microbial activity is the cause of a variety of problems in water injection systems, e.g., microbial corrosion, plugging, and biofouling. Efficient monitoring of Saudi Aramco’s vast water injection system requires th...Microbial activity is the cause of a variety of problems in water injection systems, e.g., microbial corrosion, plugging, and biofouling. Efficient monitoring of Saudi Aramco’s vast water injection system requires the development of online and automated technologies for monitoring microbial activities in the system. A previous system review and technology screening has identified five single-analyte strategies [1], which were evaluated in this study with a laboratory-scale setup to determine their applicability for automated determination of microbial activity in the injection water system. Four of the five single-analyte measuring principles tested in the laboratory setup were deemed less suitable for automation and/or reliable for use in the detection of microbial activity in the company injection water system. These four principles were: luminescence assay for adenosine-5’-triphosphate (ATP), detection and electrochemical measurements of H<sub>2</sub>S, determination of pH by electrochemical sensor, and measurement of oxidation-reduction potential (ORP). The strategy of staining cells with fluorescent DNA dyes, followed by quantification of fluorescence signals, was identified to hold, with proper optimization of DNA staining and fluorescence detection, a very promising potential for integration in automated, online sensors for microbial activity in the injection water system.展开更多
Microbial activity in the water injection system in oil and gas industry leads to an array of challenges, including biofouling, injectivity loss, reservoir plugging, and microbiologically influenced corrosion (MIC). A...Microbial activity in the water injection system in oil and gas industry leads to an array of challenges, including biofouling, injectivity loss, reservoir plugging, and microbiologically influenced corrosion (MIC). An effective mitigation strategy requires online and real-time monitoring of microbial activity and growth in the system so that the operators can apply and adjust counter-measures quickly and properly. The previous study [1] identified DNA staining technology-with PicoGreen and SYBR Green dyes—as a very promising method for automated, online determination of microbial cell abundance in the vast Saudi Aramco injection seawater systems. This study evaluated DNA staining technology on detection limit, automation potential, and temperature stability for the construction of automated sensor prototype. DNA staining with SYBR Green dye was determined to be better suited for online and real-time monitoring of microbial activity in the Saudi Aramco seawater systems. SYBR Green staining does not require sample pre-treatment, and the fluorescence signal intensity is more stable at elevated temperatures up to 30℃. The lower detection limit of 2 × 10<sup>3</sup>/ml was achieved under the optimized conditions, which is sufficient to detect microbial numbers in Saudi Aramco injection seawater. Finally, the requirements for design and construction of SYBR-based automated sensor prototype were determined.展开更多
Microbial growth in the water injection system is a well-known problem with severe operational and financial consequences for the petroleum industry, including microbiologically influenced corrosion (MIC), reduced inj...Microbial growth in the water injection system is a well-known problem with severe operational and financial consequences for the petroleum industry, including microbiologically influenced corrosion (MIC), reduced injectivity, reservoir plugging, production downtime, and extensive repair costs. Monitoring of system microbiology is required in any mitigation strategy, enabling operators to apply and adjust countermeasures properly and in due time. In previous studies [1] [2], DNA staining technology with SYBR Green dye was evaluated to have a sufficient detection limit and automation potential for real-time detection of microbial activity in the Saudi Aramco injection seawater. In this study, technical requirements and design solutions were defined, and an autonomous microbe sensor (AMS) prototype was constructed, tested and optimized in the laboratory, and validated in the field for automated detection of microorganisms in the harsh Saudi Arabia desert environment and injection seawater. The AMS prototype was able to monitor and follow the general microbial status in the system, including detection of periods with increased microbial growth or decreased microbial numbers following biocide injection. The infield AMS detection limit was 10<sup>5</sup> cells/mL. The long-term field testing also identified the areas for technical improvement and optimization for further development of a more robust and better performing commercial microbial sensing device.展开更多
A new carbazole tricationic salt,4,4'-(1E,1'E)-2,2'-(9-(2-(1-(2-hydroxyethyl)pyridinium-4-yl)ethyl)-9H-carbazole-3,6-diyl) bis(ethane-2,1-diyl) bis(1-(2-hydroxyethyl)pyridinium) iodide (THEPC) was synthesi...A new carbazole tricationic salt,4,4'-(1E,1'E)-2,2'-(9-(2-(1-(2-hydroxyethyl)pyridinium-4-yl)ethyl)-9H-carbazole-3,6-diyl) bis(ethane-2,1-diyl) bis(1-(2-hydroxyethyl)pyridinium) iodide (THEPC) was synthesized. Photophysical experiments have shown that THEPC has large two-photon excited fluorescence action cross-sections (33 GM in the presence of DNA),which ranks THEPC as a good biological fluorophore. The results from electronic absorption,circle dichroism and single-/two-photon fluorescence emission spectra suggest that THEPC can strongly bind to DNA,with an intrinsic binding constant of 5.79 × 106 L mol-1. THEPC has better photostability under one-or two-photon excitation conditions. Finally,the staining photos from two-photon fluorescence microscopy (TPM) show that THEPC can exclusively label the nucleus with high contrast and without image distortion. These remarkable properties and optimized imaging ability make THEPC an attractive DNA probe in TPM.展开更多
Biocides are oilfield chemicals that are widely used to control bacterial activity throughout the oil industry. A feasibility study has been explored to develop detection techniques for biocide batch treatments, prefe...Biocides are oilfield chemicals that are widely used to control bacterial activity throughout the oil industry. A feasibility study has been explored to develop detection techniques for biocide batch treatments, preferably on-line and in real-time, for their potential use in seawater flooding system. Several methods to measure key components of the biocide formulation were investigated and reported in previous study [1]. The enzymatic activity of an immobilized acetylcholine esterase (AChE) on the column material was successfully inhibited by some model compounds, but not by the actual biocides commonly used in Saudi Aramco seawater flooding system. In this paper, an alternative assay for biocide detection in the Saudi Aramco seawater flooding system was investigated for its applicability for the development of on-line biocide sensor. The assay was based on the detection of aldehyde functionality in the biocide mixture through measurement of a fluorescent derivative formed in the reaction of aldehyde groups and dimedone in the presence of ammonium acetate. The reaction of aldehyde groups with dimedone was demonstrated in seawater matrix, and the formed fluorescent product was successfully measured. The results showed that the dimedone-based assay was very sensitive, and relatively straightforward to perform. The ruggedness test also indicated that the assay is sensitive to minor changes of various specific conditions of the method. It is concluded that the dimedone assay is suitable for further development of a real-time biocide monitoring system to detect the presence of biocide slugs in seawater flooding system. The development of an automated on-line biocide sensor based on dimedone assay is underway.展开更多
文摘Microbial activity is the cause of a variety of problems in water injection systems, e.g., microbial corrosion, plugging, and biofouling. Efficient monitoring of Saudi Aramco’s vast water injection system requires the development of online and automated technologies for monitoring microbial activities in the system. A previous system review and technology screening has identified five single-analyte strategies [1], which were evaluated in this study with a laboratory-scale setup to determine their applicability for automated determination of microbial activity in the injection water system. Four of the five single-analyte measuring principles tested in the laboratory setup were deemed less suitable for automation and/or reliable for use in the detection of microbial activity in the company injection water system. These four principles were: luminescence assay for adenosine-5’-triphosphate (ATP), detection and electrochemical measurements of H<sub>2</sub>S, determination of pH by electrochemical sensor, and measurement of oxidation-reduction potential (ORP). The strategy of staining cells with fluorescent DNA dyes, followed by quantification of fluorescence signals, was identified to hold, with proper optimization of DNA staining and fluorescence detection, a very promising potential for integration in automated, online sensors for microbial activity in the injection water system.
文摘Microbial activity in the water injection system in oil and gas industry leads to an array of challenges, including biofouling, injectivity loss, reservoir plugging, and microbiologically influenced corrosion (MIC). An effective mitigation strategy requires online and real-time monitoring of microbial activity and growth in the system so that the operators can apply and adjust counter-measures quickly and properly. The previous study [1] identified DNA staining technology-with PicoGreen and SYBR Green dyes—as a very promising method for automated, online determination of microbial cell abundance in the vast Saudi Aramco injection seawater systems. This study evaluated DNA staining technology on detection limit, automation potential, and temperature stability for the construction of automated sensor prototype. DNA staining with SYBR Green dye was determined to be better suited for online and real-time monitoring of microbial activity in the Saudi Aramco seawater systems. SYBR Green staining does not require sample pre-treatment, and the fluorescence signal intensity is more stable at elevated temperatures up to 30℃. The lower detection limit of 2 × 10<sup>3</sup>/ml was achieved under the optimized conditions, which is sufficient to detect microbial numbers in Saudi Aramco injection seawater. Finally, the requirements for design and construction of SYBR-based automated sensor prototype were determined.
文摘Microbial growth in the water injection system is a well-known problem with severe operational and financial consequences for the petroleum industry, including microbiologically influenced corrosion (MIC), reduced injectivity, reservoir plugging, production downtime, and extensive repair costs. Monitoring of system microbiology is required in any mitigation strategy, enabling operators to apply and adjust countermeasures properly and in due time. In previous studies [1] [2], DNA staining technology with SYBR Green dye was evaluated to have a sufficient detection limit and automation potential for real-time detection of microbial activity in the Saudi Aramco injection seawater. In this study, technical requirements and design solutions were defined, and an autonomous microbe sensor (AMS) prototype was constructed, tested and optimized in the laboratory, and validated in the field for automated detection of microorganisms in the harsh Saudi Arabia desert environment and injection seawater. The AMS prototype was able to monitor and follow the general microbial status in the system, including detection of periods with increased microbial growth or decreased microbial numbers following biocide injection. The infield AMS detection limit was 10<sup>5</sup> cells/mL. The long-term field testing also identified the areas for technical improvement and optimization for further development of a more robust and better performing commercial microbial sensing device.
基金supported by the National Natural Science Foundation of China (50673053, 50173015, 30771091 and 50721002)National Science Foundation of China/the Hong Kong Research Grants Council (50218001)
文摘A new carbazole tricationic salt,4,4'-(1E,1'E)-2,2'-(9-(2-(1-(2-hydroxyethyl)pyridinium-4-yl)ethyl)-9H-carbazole-3,6-diyl) bis(ethane-2,1-diyl) bis(1-(2-hydroxyethyl)pyridinium) iodide (THEPC) was synthesized. Photophysical experiments have shown that THEPC has large two-photon excited fluorescence action cross-sections (33 GM in the presence of DNA),which ranks THEPC as a good biological fluorophore. The results from electronic absorption,circle dichroism and single-/two-photon fluorescence emission spectra suggest that THEPC can strongly bind to DNA,with an intrinsic binding constant of 5.79 × 106 L mol-1. THEPC has better photostability under one-or two-photon excitation conditions. Finally,the staining photos from two-photon fluorescence microscopy (TPM) show that THEPC can exclusively label the nucleus with high contrast and without image distortion. These remarkable properties and optimized imaging ability make THEPC an attractive DNA probe in TPM.
文摘Biocides are oilfield chemicals that are widely used to control bacterial activity throughout the oil industry. A feasibility study has been explored to develop detection techniques for biocide batch treatments, preferably on-line and in real-time, for their potential use in seawater flooding system. Several methods to measure key components of the biocide formulation were investigated and reported in previous study [1]. The enzymatic activity of an immobilized acetylcholine esterase (AChE) on the column material was successfully inhibited by some model compounds, but not by the actual biocides commonly used in Saudi Aramco seawater flooding system. In this paper, an alternative assay for biocide detection in the Saudi Aramco seawater flooding system was investigated for its applicability for the development of on-line biocide sensor. The assay was based on the detection of aldehyde functionality in the biocide mixture through measurement of a fluorescent derivative formed in the reaction of aldehyde groups and dimedone in the presence of ammonium acetate. The reaction of aldehyde groups with dimedone was demonstrated in seawater matrix, and the formed fluorescent product was successfully measured. The results showed that the dimedone-based assay was very sensitive, and relatively straightforward to perform. The ruggedness test also indicated that the assay is sensitive to minor changes of various specific conditions of the method. It is concluded that the dimedone assay is suitable for further development of a real-time biocide monitoring system to detect the presence of biocide slugs in seawater flooding system. The development of an automated on-line biocide sensor based on dimedone assay is underway.
