Real-Time Monitoring of Gas-Phase and Dissolved CO2 Using a Mixed-Matrix Composite Integrated Fiber Optic Sensor for Carbon Storage Application.

Novel chemical sensors that improve detection and quantification of CO2 are critical to ensuring safe and cost-effective monitoring of carbon storage sites. Fiber optic (FO)-based chemical sensor systems are promising field-deployable systems for real-time monitoring of CO2 in geological formations for long-range distributed sensing. In this work, a mixed-matrix composite integrated FO sensor system was developed with a purely optical readout that reliably operates as a detector for gas-phase and dissolved CO2. A mixed-matrix composite sensor coating consisting of plasmonic nanocrystals and hydrophobic zeolite embedded in a polymer matrix was integrated on the FO sensor. The mixed-matrix composite FO sensor showed excellent reversibility/stability in a high humidity environment and sensitivity to gas-phase CO2 over a large concentration range. This remarkable sensing performance was enabled by using plasmonic nanocrystals to significantly enhance the sensitivity and a hydrophobic zeolite to effectively mitigate interference from water vapor. The sensor exhibited the ability to sense CO2 in the presence of other geologically relevant gases, which is of importance for applications in geological formations. A prototype FO sensor configuration, which possesses a robust sensing capability for monitoring dissolved CO2 in natural water, was demonstrated. Reproducibility was confirmed over many cycles, both in a laboratory setting and in the field. More importantly, we demonstrated on-line monitoring capabilities with a wireless telemetry system, which transferred the data from the field to a website. The combination of outstanding CO2 sensing properties and facile coating processability makes this mixed-matrix composite FO sensor a good candidate for practical carbon storage applications.

Historic and Modern Approaches for the Discovery of Abandoned Wells for Methane Emissions Mitigation in Oil Creek State Park, Pennsylvania.

Hundreds of oil wells were drilled along Oil Creek in Pennsylvania in the mid-1800s, birthing the modern oil industry. No longer in operation, many wells are now classified as abandoned, and, due to their age, their locations are either unknown or inaccurately recorded. These historic-well sites present environmental, safety, and economic concerns in the form of possible methane leaks and physical hazards. Airborne magnetic and LiDAR surveys were conducted in the Pioneer Run watershed in Oil Creek State Park to find abandoned wells in a historically significant but physically challenging location. Wells were drilled in this area prior to modern geolocation and legal documentation. Although a large number of old wells were abandoned summarily without remediation of the site, much of the land area within Oil Creek State Park is now covered in trees and dense underbrush, which can obscure wellheads. The thick vegetation and steep terrain limited the possibility of ground-based surveys to easily find well sites for methane emissions studies. The data from remote sensing surveys were used to corroborate potential well locations from historic maps and photographs. Potential well sites were verified in a ground-based field survey and monitored for methane emissions. Two historic photographs documenting oil activity in the late 1800s were georeferenced using a combination of magnetic and LiDAR data. LiDAR data, which were more useful in georeferencing and in field verification, identified 290 field locations in the Pioneer Run watershed, 86% of which were possible well sites. Sixty-two percent of the ground-verified wells remained unplugged and comprised the majority of leaking wells. The mean methane emissions factor for unplugged wells was 0.027 ± 0.099 kg/day, lower than other Appalachian Basin methane emissions estimates. LiDAR was used for the first time, in combination with an airborne magnetic survey, to reveal underground oil industry features and inform well identification and remediation efforts in difficult-to-navigate regions. In the oldest oil fields, where well casing has been removed or wood conductor casing was installed, historic photographs provide additional lines of evidence for oil wells where ground disturbances have concealed surface features. Identification of well sites is necessary for mitigation efforts, as unplugged wells emit methane, a potent greenhouse gas.

Historic and modern approaches for discovery of abandoned wells for methane emissions mitigation in Oil Creek State Park, Pennsylvania.

BACKGROUND: Hundreds of oil wells were drilled along Oil Creek in Pennsylvania in the mid-1800s, birthing the modern oil industry. No longer in operation, many wells are now classified as abandoned, and, due to their age, their locations are either unknown or inaccurately recorded. These historic well sites present environmental, safety, and economic concerns in the form of possible methane leaks and physical hazards. METHODS: Airborne magnetic and LiDAR surveys were conducted in the Pioneer Run watershed in Oil Creek State Park to find abandoned wells in a historically significant but physically challenging location. Wells were drilled in this area prior to modern geolocation and legal documentation. Although a large number of old wells were abandoned summarily without remediation of the site, much of the land area within Oil Creek State Park is now covered in trees and dense underbrush, which can obscure wellheads. The thick vegetation and steep terrain limited the possibility of ground-based surveys to easily find well sites for methane emissions studies. The data from remote sensing surveys were used to corroborate potential well locations from historic maps and photographs. Potential well sites were verified in a ground-based field survey and monitored for methane emissions. RESULTS: Two historic photographs documenting oil activity in the late 1800s were georeferenced using a combination of magnetic and LiDAR data. LiDAR data, which were more useful in georeferencing and in field verification, identified 290 field locations in the Pioneer Run watershed, 86% of which were possible well sites. Sixty-two percent of the ground-verified wells remained unplugged and comprised the majority of leaking wells. The mean methane emissions factor for unplugged wells was 0.027 ± 0.099 kg/day, lower than other Appalachian Basin methane emissions estimates. CONCLUSIONS: LiDAR was used for the first time, in combination with an airborne magnetic survey, to reveal underground oil industry features and inform well identification and remediation efforts in difficult-to-navigate regions. In the oldest oil fields, where well casing has been removed or wood conductor casing was installed, historic photographs provide additional lines of evidence for oil wells where ground disturbances have concealed surface features. Identification of well sites is necessary for mitigation efforts, as unplugged wells emit methane, a potent greenhouse gas.

Constraining natural gas pipeline emissions in San Juan Basin using mobile sampling.

Quantifying methane (CH4) leaks of pipeline systems is critical to ensure accurate emission factors in regional and global atmospheric models. The previous emission factors in the United States Environmental Protection Agency (EPA) Greenhouse Gas Inventory (GHGI) are from 1996 and do not reflect the modern gathering pipeline system. Additional data from different basins across the United States are urgently needed to improve the emission factors. The National Energy Technology Laboratory conducted a ground-based vehicle survey at Carson National Forest in the San Juan Basin, New Mexico, in September 2019. 187 km of natural gas gathering pipeline systems were surveyed. The mobile CH4 survey system was efficient in identifying CH4 plumes and pinpointing the leak sources. Gaussian dispersion modeling suggested our survey system had a minimum detection limit of 1.5 LPM. No leaks were found from the pipelines while a leak of 7.1 +/- 0.2 LPM was on a pig launcher door and another leak of 0.7 +/- 0.1 LPM on a block valve. Limited access to the gathering pipeline system prevented us from quantifying all potential leaks detected by the CH4 sensors. The low leak frequency phenomenon was also observed in the sole existing study of natural gas gathering pipelines in the Fayetteville Shale.

Quantifying source contributions of volatile organic compounds under hydraulic fracking moratorium.

Volatile organic compounds (VOCs) are precursors for ozone (O3) and secondary particulate matter, which contribute to asthma and cardiovascular diseases. With the technology development of hydraulic fracking, the United States experienced a shale gas boom in the last decade while the public raised concerns about the potential health impacts of co-emitted VOCs and other airborne pollutants. National Energy Technology Laboratory conducted stationary trailer-based ambient monitoring to study the sources of VOCs in Maryland, where the state enacted a moratorium on unconventional natural gas extraction. The campaign had two periods, May to August 2014 (summer) and November 2014 to February 2015 (winter). Ethane was the most abundant VOC, averaging 12.3 ppb (SD = 15.7 ppb) in summer and 21.7 ppb (SD = 21.6 ppb) in winter. The seasonal variation of VOCs indicated different source strengths. The sampling region was in the nitrogen oxides (NOx) limited regime for O3 production, and the O3 concentrations were sensitive to VOC/NOx ratios in the early mornings. We derived a six-factor profile using positive matrix factorization: motor vehicles, industrial, biogenics, coal burning, fugitive and evaporative, and ozone secondary. The fugitive and evaporative factor explained 44.5% of total VOCs, and the motor vehicles factor followed second with 15.5%. Oil and gas activities had a considerable impact on the abundance of VOCs in this region.

Oxindole derivatives as inhibitors of TAK1 kinase.

Several series of oxindole analogues were synthesized and screened for inhibitory activity against transforming growth factor-ß-activating kinase 1 (TAK1). Modifications around several regions of the lead molecules were made, with a distal hydroxyl group in the D region being critical for activity. The most potent compound 10 shows an IC(50) of 8.9 nM against TAK1 in a biochemical enzyme assay, with compounds 3 and 6 showing low micromolar cellular inhibition.

Inhibition of eEF2-K by thieno[2,3-b]pyridine analogues.

Several series of thieno[2-3-b]pyridine analogues were synthesized and screened for inhibitory activity against eukaryotic elongation factor-2 kinase (eEF2-K). Modifications around several regions of the lead molecules were made, with a ring fusion adjacent to the nitrogen on the thienopyridine core being critical for activity. The most active compound 34 shows an IC(50) of 170 nM against eEF2-K in vitro.

Synthesis of the core structure of acutumine.

[reaction: see text] The tricyclic core of the bioactive natural product acutumine has been synthesized. Key steps include an oxidative phenolic coupling to form a masked o-benzoquinone, an anionic oxy-Cope rearrangement to construct an all-carbon quaternary center, and a Michael-type cyclization to form an amine-bearing quaternary carbon. The target compound exists in solution as an enol, in contrast to related compounds that are ketones. A model explaining these observations is presented.