High Levels Of Methane Research Articles

Evaluation of Korean methane emission sources with satellite retrievals by spatial correlation analysis

Methane is a significant greenhouse gas (GHG), and it is imperative to understand its spatiotemporal distribution and primary sources in areas with higher methane concentrations, as such insights are essential for informing effective mitigation policies. In this study, we employed TROPOMI satellite retrievals to analyze the spatiotemporal patterns of methane distributions and identify major emission sources in South Korea over the period from August 2018 to July 2019. Additionally, we examined the spatial correlations between satellite methane retrievals and emission sources to characterize regions with higher methane levels on an annual basis.Concerning spatial distributions, concentrations exceeding 1870 ppb were predominantly observed in western non-mountainous regions, particularly in rice paddy areas. Moreover, sporadic concentrations exceeding 1880 ppb were detected in large ports and industrial zones, primarily located in coastal regions of South Korea.Our spatial correlation analysis, conducted using the SDMSelect method, identified specific emissions contributing to regions with higher methane concentrations. There were some areas with relatively strong correlations between high XCH4 and emissions from the domestic livestock industry, fossil fuel utilization (specifically, the oil and gas sector), landfills, and rice paddies. This analysis, incorporating domestic emission inventories and satellite data, provides valuable insights into the characteristics of regional methane concentrations. In addition, this analysis can assess national methane emissions inventories, where there is limited information on the spatial distributions, offering critical information for the prioritization of domestic regional policies aimed at reducing greenhouse gas emissions.

Developing basin-specific emission factors for accurate methane inventory and emission reduction strategies in Zonguldak Coal Basin, Turkey: Implications for enhancing safety and sustainability

This study develops basin-specific emission factors using historical coal production and methane emissions data to enhance methane inventories and emission reduction strategies in Turkey's Zonguldak Coal Basin. The basin is known for high levels of coal mine methane (CMM) emissions, posing a serious safety hazard to miners and affecting mine productivity. However, limited data on in-situ parameters related to Coal Mine Methane (CMM) emissions have been available. The study analyzes historical trends in CMM emissions (1980–2020) from the basin's underground coal mines, revealing declining emissions alongside coal production. Over this period, approximately 2.28 billion cubic meters of CMM were released. Continued historical coal production rates suggest a significant 6.63 MWe power generation potential. The investigation into coal production, average mining depth, and coal seam gas content reveal that CMM emissions primarily depend on coal production and mining depth. Utilizing available methane mitigation technologies could prevent an estimated 55.7 million tons of methane annually (equivalent to around 692,000 tons of CO2e). Importantly, the study calculates basin-specific emission factors (ranging from 7.24 m3/t to 21.66 m3/t) based on historical measurements, providing a more accurate regional representation than the Intergovernmental Panel on Climate Change (IPCC) default values. These factors are vital for identifying high-emission areas and guiding emission reduction strategy development. This study addresses a critical data gap in Turkey's estimation of methane emissions from underground coal mining, particularly in the Zonguldak coal basin. It establishes a foundation for future research on methane emissions from coal mines at various scales, contributing to improved understanding, emissions mitigation, safety enhancement, and sustainable coal mining practices.

Can Polar Stratospheric Clouds Explain Arctic Amplification?

Abstract Climate models underestimate the magnitude of Arctic warming in past warm climates, like the early Cretaceous and Paleogene periods, implying that certain physical processes might be missing or poorly represented. Previous studies suggest that a large increase in wintertime Arctic polar stratospheric clouds (PSCs) might have promoted Arctic amplification through additional greenhouse warming. High methane concentrations in warm climates might have increased stratospheric water vapor providing favorable conditions for PSCs. However, methane concentrations in past warm climates are extremely uncertain. Here, we revisit the PSC hypothesis by exploring PSC changes under very high methane levels, 4× preindustrial carbon dioxide, and strong polar-amplified surface warming, using a whole-atmosphere model with fully interactive chemistry. We find that with polar-amplified warming there is a large increase in Arctic outgoing longwave radiation (OLR) that reduces as the methane concentration is increased. PSCs increase monotonically with methane concentration. A large radiative cooling and an increase in water vapor in the stratosphere increases Arctic PSCs, which follow a power law with respect to relative humidity. Using a two-way partial radiative perturbation technique, we show that the OLR reduction due to PSCs is similar to the direct radiative forcing of methane for high methane levels. Thus, we find that PSCs could play an important role in Arctic warming in a warmer-than-present-day climate, but only if methane levels were higher than suggested by previous modeling studies for past warm climates.

Road salting and natural brine migration revealed as major sources of groundwater contamination across regions of northern Appalachia with and without unconventional oil and gas development

High methane and salt levels in groundwater have been the most widely cited unconventional oil and gas development (UOGD) related water impairments. The attribution of these contaminants to UOGD is usually complex, especially in regions with mixed land uses. Here, we compiled a large hydrogeochemistry dataset containing 13 geochemical analytes for 17,794 groundwater samples from rural northern Appalachia, i.e., 19 counties located on the boundary between Pennsylvania (PA; UOGD is permitted) and New York (NY; UOGD is banned). With this dataset, we explored if statistical and geospatial tools can help shed light on the sources of inorganic solutes and methane in groundwater in regions with mixed land uses. The traditional Principal Component Analysis (PCA) indicates salts in NY and PA groundwater are mainly from the Appalachian Basin Brine (ABB). In contrast, the machine learning tool – Non-negative Matrix Factorization (NMF) highlights that road salts (in addition to ABB) account for 36%–48% of total chloride in NY and PA groundwaters. The PCA fails to identify road salts as one water/salt source, likely due to its geochemical similarity with ABB. Neither PCA nor NMF detects a regional impact of UOGD on groundwater quality. Our geospatial analyses further corroborate (1) road salting is the major salt source in groundwater, and its impact is enhanced in proximity to highways; (2) UOGD-related groundwater quality deterioration is only limited to a few localities in PA.

Metagenomic Predictions: A Review 10 years on.

Metagenomic predictions use variation in the metagenome (microbiome profile) to predict the unknown phenotype of the associated host. Metagenomic predictions were first developed 10 years ago, where they were used to predict which cattle would produce high or low levels of enteric methane. Since then, the approach has been applied to several traits and species including residual feed intake in cattle, and carcass traits, body mass index and disease state in pigs. Additionally, the method has been extended to include predictions based on other multi-dimensional data such as the metabolome, as well to combine genomic and metagenomic information. While there is still substantial optimisation required, the use of metagenomic predictions is expanding as DNA sequencing costs continue to fall and shows great promise particularly for traits heavily influenced by the microbiome such as feed efficiency and methane emissions.

Maternal Exposure to Air Pollution Is Associated with Neonatal Jaundice: A Retrospective Cohort Study

To evaluate the association between maternal ambient pollutant exposure and neonatal jaundice in multiple pollutant species and examine sex differences. Epidemiologic study: Records of 13 297 newborns (6153 male, 7144 female) born in Taichung, Taiwan were obtained from a national database. Average concentrations of prenatal air pollutants 3months prior to birth were divided into low, middle, and high levels. Neonatal jaundice phototherapy rates between mothers who suffered varying air pollutant levels were compared. Clinical study: Three hundred seventy-six newborns (189 male, 187 female) born and received jaundice treatment with phototherapy in a hospital in Taichung, Taiwan were recruited. The correlation between prenatal exposure to air pollutants 3months prior to birth, newborn's serum bilirubin, and serum hemoglobin were calculated. Epidemiologic study: Male newborns born to mothers exposed to high carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO2), and methane (CH4) levels had higher phototherapy rates. In female newborns, the same was noted for CO and CH4. Clinical study: Male newborns had a positive correlation between CO, ≤2.5μm diameter particles, ≤10μm diameter particles, NO, NO2, nonmethane hydrocarbon, and CH4 exposure 3months prior to birth and serum bilirubin levels. Female newborns had a positive correlation for CH4. A positive correlation between CO, ≤2.5μm diameter particles, ≤10μm diameter particles, NO2, nonmethane hydrocarbon, CH4 exposure, and serum hemoglobin levels was noted in male newborns. Maternal exposure to air pollutants may increase neonatal jaundice treatment rates for phototherapy and higher neonatal serum total bilirubin level. Higher hemoglobin levels because of higher pollutant exposures may explain our findings. The association was more obvious in male newborns.

Измерения фоновой концентрации метана дистанционным лидаром на километровых трассах в районе Московской области.

Local path measurements of the background methane concentration in the northeast of the Moscow Region were carried out using a remote active lidar based on a powerful Raman amplifier of optical radiation in the wavelength range of ~ 1650 nm. The radiation power in the pulse was about 3 W. The trasses were selected taking into account possible anomalous deviations of the background of atmospheric methane and included forests, gasified buildings with natural gas, a peat lake, a road with heavy traffic, a livestock farm and a solid waste landfill. The length of the distances ranged from ~ 0.6 km to ~ 3.15 km. The highest background concentration of methane was observed over a livestock farm, over a highway and a solid waste landfill, which confirms the fact of an increase in gas emissions over these facilities. Also higher methane levels were observed above of the gasified homes and the heavy traffic road, indicating a possible increase in the number of vehicles using methane as fuel and a possible leak of natural gas from pipelines supplying buildings with natural gas.

Evaluation of CH4 Emission in Two Paddy Field Areas, Khonkaen and Ayutthaya, in Thailand

It is well known that submerged soils emit high levels of methane (CH4) due to oxygen deprivation and free iron oxide causing a quick reduction. However, there are other soil properties that control the reduction processes in soil, especially the amount of soil organic carbon (SOC). This study aimed to investigate the major factors controlling CH4 production potential (CH4PP) in Thai paddy fields. Two provinces, Ayutthaya, a clay soil region, and Khonkaen, a sandy soil region, were selected to represent a wide range of soil textures. Soil characteristic analysis pre- and post-incubation, and weekly gas detection in an incubation experiment over two months, was conducted. Stepwise multiple regression analysis was employed to analyze major soil factors controlling CH4PP. For the regional prediction of CH4PP, a map dataset of Ayutthaya and Khonkaen by the Land Development Department, Thailand, and a soil texture map (with intersected point data using the soil property map in ArcGIS) by OpenLandMap, were used. CH4PP was correlated with 1:10 pH, Fe2+, and water-soluble organic carbon (WSOC) measured after incubation. Although CH4PP showed no significant correlation with any soil properties measured before incubation, CH4PP was correlated with SOC, 1:10 electrical conductivity (EC), exchangeable ammonium (ExNH4), and sand content. It was thought that SOC and ExNH4 were related to organic matter decomposition, 1:10 EC was related to SO42− reduction and sand content was related to free oxides. Predicted regional CH4PP was similar in Ayutthaya and Khonkaen, although SOC, ExNH4 and 1:10 EC was higher, and sand content was lower in Ayutthaya than in Khonkaen. In both regions, the distribution of CH4PP corresponded to SOC, and CH4PP was lower with lower sand content and higher 1:10 EC. In clayey Ayutthaya, higher CH4PP was observed in the area with higher ExNH4. This indicates that soil properties other than soil texture and SOC influence CH4PP in the paddy fields in Thailand.

Proactive interburden fracturing using UIS drilling with validation monitoring

A series of gas inrush events occurred during development at Grosvenor Mine resulting in exposure to elevated levels of methane at the production face. A total of 22 gas inrush events occurred, with between 15 and 130 m3 of methane released during each event. The presence of an undrained seam in the immediate floor, geotechnical characteristics of the floor, and the stress environment all contributed to these dynamic floor events, while the geological characteristics of the seam below, such as the seam thickness and ash content of 75%, prevented effective predrainage. However, events only occurred in headings mined parallel to the principal horizontal stress direction. In cut-throughs (C/T) perpendicular to the principal stress direction no events occurred, and higher methane levels were observed at the production face. The solution to preventing the gas inrush events involved creating a conduit in the interburden between the mined seam and the seam in the immediate floor to allow the gas to be drained during the development of the headings, as occurred in the cut-throughs (cut-through and cross-cut are regional terms that are analogous). A series of underground inseam (UIS) holes were drilled using the directional drill rig with the aim of fracturing this interburden ahead of the face and promote floor failure to allow the gas to release consistently. The floor fracturing was conducted using water pressure generated from a longwall salvage pump, with the current UIS drilling equipment retrofitted with a series of subs, packers and a fracturing tool. The packers and the fracturing tool were shifted to desired locations along the drilled UIS borehole to achieve the required fracture. The fractures were monitored using a proving hole and with a HYDAC data logger attached to the salvage pack, with the results analysed on the surface to ensure connectivity to the working seam.

LCO2-ECBM technology for preventing coal and gas outburst: Integrated effect of permeability improvement and gas displacement

More than 60% of China’s coal seams have the feature of low permeability, which severely restricts the gas drainage efficiency when using traditional drilling method. The development of enhanced coalbed methane (ECBM) technologies is essential to prevent coal and gas outburst (CGO) disasters caused by high levels of coal bed methane (CBM). This paper proposes an ECBM technology by liquid carbon dioxide (LCO2-ECBM), based on permeability improvement by thermal damage and CO2-CH4 displacement effect. In-situ experiment conducted in the No. 6 coal seam of Zhangji mine shows the effectiveness of LCO2-ECBM technology, which had drainage efficiency 1.9 times higher than that of the traditional drilling method. The mechanisms of LCO2-ECBM recovery were theoretically deduced and experimentally verified. The evolution of adsorbed pores (ADP) and seepage pores (SEP) in coal samples before and after LCO2 saturation were revealed. The ADP specific area, SEP volume, and permeability in the saturated coal samples were both greater than those of the raw ones. Moreover, the periodic features of binary-gas competitive adsorption in ADP and SEP were revealed by the variation of the CH4 concentration in the displacement test. The feasibility of LCO2-ECBM technology was proved by in-situ experiment and laboratory tests, and it provided a new means for preventing CGO hazards.

Effect of pretreatments on cellulosic composition and morphology of pine needle for possible utilization as substrate for anaerobic digestion

Waste residues from agricultural and forest resources have received much attention as potential source of lignocellulosic biomass (LCB) especially after the “food-versus-fuel” conflict. Therefore, exploring the potential of LCB (especially forest biomass) as a resource for sustainable bioenergy generation is highly promising. The present study reports the structural modification in the cross-linking of lignocellulosic complex in pine needle forest biomass after pretreatments: milling, steam explosion and acid-base-acid treatments. The changes in morphology and composition of the cellulose and lignin in pine needles after pretreatments was evaluated using Field Emission Scanning Electron Microscopy (FE-SEM), Fourier Transform Infrared (FT-IR) microspectroscopy, Energy Dispersive Spectroscopy (EDS) and Scanning Electron Microscopy (SEM). Field Emission Scanning Electron micrographs revealed that pretreatments resulted in changes in orderly arrangement of interwoven fibrils, surface abnormalities in cells surrounding stomatal opening and exposure of vascular bundle. FT-IR of pretreated substrate indicated significant changes in functional moieties of ester bond between lignin and hemicelluloses, phenol hydroxyl moieties and aromatic ring associated with lignin and hydrogen bonding in cellulose. The findings in the present study thus open up avenues for exploring potential of pretreated pine needles for renewable bioenergy generation. Anaerobic digestion (AD) of the pretreated biomass resulted in 21.4% higher methane levels as compared to untreated pine litter. Appearance of lignin droplets and deposition of coalescent materials on pre-treated biomass surface was also observed in the present study. These colloidal lignin particles could serve as potential nanocomposites, for application in biomaterial applications.

A Fiber Bragg Grating (FBG)-Based Sensor System for Anaerobic Biodigester Humidity Monitoring

An operational, Fiber Bragg Grating (FBG)-based sensing system, specifically designed to monitor conditions in a harsh industrial environment is reported. The sensors used were placed inside tanks with high levels of methane (CH4), carbon dioxide (CO2) and hydrogen sulphide (H2S) gases and high relative humidity in the North Head sewage treatment plant in Sydney, Australia. The sensor system was developed primarily to monitor the effect of >98% relative humidity and temperature changes on the corrosion rates of various materials inside the tanks. Data have been obtained from the use of the system for eight months: these have been correlated with key climate data including the changing weather conditions experienced during the continued monitoring activity. The sensor system specifically developed has been shown to be sufficiently robust to work well, and safely, in such a harsh environment (due to the gaseous H2S and CH4 present) with no signs of deterioration of the sensors or of the signals obtained from the system. The remote operation through flexible data transmission has allowed continuous and up-to-date monitoring of the conditions inside the tanks.

Arctic Plankton Populations Vary by Season

Planktonic foraminifera and sea snail numbers swell from April to June in the Barents Sea, but contrary to predictions, the organisms do not appear to be affected directly by high methane levels.

Calibration-free breath acetone sensor with interference correction based on wavelength modulation spectroscopy near 8.2 $$\upmu$$m

Development of a robust breath acetone sensor based on laser absorption of multiple species near 8.2 $$\upmu$$m is presented. A scanned-wavelength modulation spectroscopy technique, involving intensity-normalized second harmonic detection, was paired with a multi-pass optical gas cell to attain signals related to differential absorbance of acetone, water vapor, and methane. A spectral fitting routine of the harmonic signals was used to infer the respective abundances of each species, correcting the acetone signal for interfering absorption. A detection limit ($$2\sigma$$) of approximately 0.11 ppm acetone was determined based on controlled measurements using reference test gases. The sensor was further tested in exhaled breath samples with varying amounts of interfering species, exhibiting capability for sensitive acetone detection with very high levels of exhaled methane (up to 40 ppm). The sensor is also shown to be insensitive to locally broadband interfering absorbers, namely methanol and ethanol in normal human breath. To highlight utility, the breath acetone sensor was used to track ketosis during a regimented ketogenic diet of several subjects, demonstrating regular non-intrusive monitoring of breath acetone over a clinically-relevant range (0.4–74 ppm) and sensitivity to dietary changes.

1194 Small Intestinal Bacterial Overgrowth Is Common in Mast Cell Activation Syndrome

INTRODUCTION: Mast cell activation syndrome (MCAS) often presents with symptoms of irritable bowel syndrome (IBS). MCAS is a multi-systemic disorder caused by inappropriate mast cell (MC) activation causing inflammatory and allergic symptoms. IBS can be associated with small intestinal bacterial overgrowth (SIBO). This study determined the prevalence of SIBO in MCAS. METHODS: Patients with refractory gastrointestinal (GI) symptoms were evaluated for MCAS and SIBO. MCAS was diagnosed if there were typical symptoms of mast cell (MC) activation in 2 or more organ systems plus 1 or more of the following: elevation of MC chemical mediator(s), clinical improvement with MC-directed therapy, and/or increased intestinal MC density. SIBO diagnosis was based on a lactulose breath test (LBT) with ≥20 ppm hydrogen rise from baseline within 90 minutes. These LBT results were compared to our prior study of healthy controls. The effect of co-morbid syndromes and medication use was analyzed. Antibiotic therapy effects were a secondary aim. This study was IRB approved. RESULTS: There were 139 MCAS subjects (116 F, 23 M, 46.6 ± 16.9 years) and 30 controls (19 F, 11 M, 44 ± 14.0 years). GI symptoms preceded other MCAS symptoms in 66.2%. Symptoms included abdominal pain (87.1%), bloating (74.8%), constipation (66.9%), diarrhea (63.3%), nausea (61.9%), heartburn (54.0%), and dysphagia (29.5%). In these MCAS patients Rome 4 criteria for IBS-mixed (39.6%), IBS-constipation (22.3%), and IBS-diarrhea (18.7%) were met. SIBO was present in 30.9% MCAS subjects vs. 10% in controls (P = 0.023). Methane excretion in a plateau pattern was common in MCAS: 10.1% had levels ≥10 ppm and 24.5% had levels 3-9 ppm. Higher methane levels were associated with IBS-constipation compared to SIBO positive subjects: 42.9% vs. 9.3% (P = 0.02). Postural orthostatic tachycardia syndrome, hypermobile Ehlers-Danlos syndrome, MC density and mediators, proton pump inhibitors, thyroid supplements, and statins were not associated with LBT changes. Antibiotics were prescribed for 74 subjects: 67.6% had marked improvement, 5.4% had partial improvement, and 21.6% had no improvement in GI symptoms. Adverse events led to cessation of antibiotics in 9.5%. CONCLUSION: SIBO with hydrogen and methane plateau patterns are common in MCAS subjects. MCAS could cause SIBO due to alterations of the GI immune system or altered motility by local release of MC mediators. Antibiotic therapy appears to improve GI symptoms in MCAS patients.

Compound-Specific Radiocarbon Analysis of Atmospheric Methane: A New Preconcentration and Purification Setup

ABSTRACTMethane contributes substantially to global warming as the second most important anthropogenic greenhouse gas. Radiocarbon (14C) measurements of atmospheric methane can be used as a source apportionment tool, as they allow distinction between thermogenic and biogenic methane sources. However, these measurements remain scarce due to labor-intensive methods required. A new setup for the preparation of atmospheric methane samples for radiocarbon analysis is presented. The system combines a methane preconcentration line with a preparative gas chromatography technique to isolate pure methane samples for a compound-specific radiocarbon analysis. In order to minimize sample preparation time, we designed a simplified preconcentration line for the extraction of methane from 50 L atmospheric air, which corresponds to 50 µg C as required for a reliable14C analysis of methane-derived CO2gas measurement with accelerator mass spectrometry (AMS). The system guarantees a quantitative extraction of methane from atmospheric air samples for14C analysis, with a good repeatability and a low processing blank. The setup was originally designed for the measurement of samples with low methane concentrations, but it can also be adapted to apportion sources from environmental compartments with high methane levels such as freshwaters or wetlands.

Interactions between anaerobic ammonium- and methane-oxidizing microorganisms in a laboratory-scale sequencing batch reactor

The reject water of anaerobic digestors still contains high levels of methane and ammonium that need to be treated before these effluents can be discharged to surface waters. Simultaneous anaerobic methane and ammonium oxidation performed by nitrate/nitrite-dependent anaerobic methane-oxidizing(N-damo) microorganisms and anaerobic ammonium-oxidizing(anammox) bacteria is considered a potential solution to this challenge. Here, a stable coculture of N-damo archaea, N-damo bacteria, and anammox bacteria was obtained in a sequencing batch reactor fed with methane, ammonium, and nitrite. Nitrite and ammonium removal rates of up to 455 mg N-NO2− L−1 day−1 and 228 mg N-NH4+ L−1 were reached. All nitrate produced by anammox bacteria (57 mg N-NO3− L−1 day−1) was consumed, leading to a nitrogen removal efficiency of 97.5%. In the nitrite and ammonium limited state, N-damo and anammox bacteria each constituted about 30–40% of the culture and were separated as granules and flocs in later stages of the reactor operation. The N-damo archaea increased up to 20% and mainly resided in the granular biomass with their N-damo bacterial counterparts. About 70% of the nitrite in the reactor was removed via the anammox process, and batch assays confirmed that anammox activity in the reactor was close to its maximal potential activity. In contrast, activity of N-damo bacteria was much higher in batch, indicating that these bacteria were performing suboptimally in the sequencing batch reactor, and would probably be outcompeted by anammox bacteria if ammonium was supplied in excess. Together these results indicate that the combination of N-damo and anammox can be implemented for the removal of methane at the expense of nitrite and nitrate in future wastewater treatment systems.

Co-occurring genomic capacity for anaerobic methane and dissimilatory sulfur metabolisms discovered in the Korarchaeota.

Phylogenetic and geological evidence supports the hypothesis that life on Earth originated in thermal environments and conserved energy through methanogenesis or sulfur reduction. Here we describe two populations of the deeply rooted archaeal phylum Korarchaeota, which were retrieved from the metagenome of a circumneutral, suboxic hot spring that contains high levels of sulfate, sulfide, methane, hydrogen and carbon dioxide. One population is closely related to 'Candidatus Korarchaeum cryptofilum OPF8', while the more abundant korarchaeote, 'Candidatus Methanodesulfokores washburnensis', contains genes that are necessary for anaerobic methane and dissimilatory sulfur metabolisms. Phylogenetic and ancestral reconstruction analyses suggest that methane metabolism originated in the Korarchaeota, whereas genes for dissimilatory sulfite reduction were horizontally transferred to the Korarchaeota from the Firmicutes. Interactions among enzymes involved in both metabolisms could facilitate exergonic, sulfite-dependent, anaerobic oxidation of methane to methanol; alternatively, 'Ca. M. washburnensis' could conduct methanogenesis and sulfur reduction independently. Metabolic reconstruction suggests that 'Ca. M. washburnensis' is a mixotroph, capable of amino acid uptake, assimilation of methane-derived carbon and/or CO2 fixation by archaeal type III-b RuBisCO for scavenging ribose carbon. Our findings link anaerobic methane metabolism and dissimilatory sulfur reduction within a single deeply rooted archaeal population and have implications for the evolution of these traits throughout the Archaea.

E&P Notes (November 2018)

E&P Notes Study Finds Methane in Water, but not From Oil Drilling Stephen Rassenfoss, JPT Emerging Technology Senior Editor A multiyear study of water wells in rural areas during intensive development in the Utica Shale found that some had high levels of methane (CH4), but chemical testing showed that was not the source of that gas. Based on the carbon isotopes identified in the well water samples collected by researchers, the methane was from shallower depths. This biogenic gas was likely produced by bacteria in places like the soil and in coal seams, according to the study in the June 2018 issue of the journal Environmental Monitoring and Assessment. There are “production-scale coalbed CH4 reserves in the study area but no active coalbed gas wells,” it said. Huge Zohr Field Off Egypt Flows at 2 Bcf/D Matt Zborowski, Technology Writer The Zohr Field offshore Egypt is now flowing at more 2 Bcf/D, or 365,000 BOE/D, less than a year after it started production. The benchmark comes as operator Eni solidifies concession agreements and ramps up exploration and development in the North African country. The Italian multinational firm has started up the project’s fifth production unit, T4, which consists of eight production wells and a 218-km, 30-in. OD pipe-line commissioned in August. Production is expected to plateau at more than 2.7 Bcf/D in 2019. US Now Top Global Oil Producer but its Limits are Showing Stephen Rassenfoss, JPT Emerging Technology Senior Editor The US has “likely surpassed” Russia as the world’s largest oil producer, according to a US Energy Information Administration (EIA) report. While that is a point of pride for US producers, over the next year US energy users likely will be hoping for more competition at the top as tighter supplies are expected to drive up oil prices. The US reached the top due to a multi-year surge in production from unconventional plays at a time when Russia and Saudi Arabia limited production growth to shrink excess inventories of crude and push up prices. Satellite Imaging Shines Light on Oil Production Sites Stephen Rassenfoss, JPT Emerging Technology Senior Editor Oil producers are a secretive lot, but satellite imaging is offering increasingly detailed reports on what is happening on the ground. Satellite imaging used by the World Bank to estimate emissions from flares burning billions of cubic meters of natural gas every year offer an indirect look at oil output. “Economics and changes in oil production result in changes in flaring,” said Martyn Howells, technical network coordinator in energy for the World Bank, adding, “The amount of gas you flare for a given volume of oil is pretty constant.” ExxonMobil Logs Another Guyana Find ExxonMobil made its ninth discovery offshore Guyana, possibly creating the greatest value of any offshore basin in the Americas. This is the company’s fifth discovery on the Stabroek Block in the past year and proves a new play concept for potential development. The Hammer-head-1 discovery encountered approximately 197 ft (60 m) of high-quality, oil-bearing sandstone reservoir. The well was safely drilled to 13,862 ft (4225 m) depth in 3,373 ft (1150 m) of water. “The Hammerhead-1 discovery reinforces the potential of the Guyana basin, where ExxonMobil is already maximizing value for all stakeholders through rapid phased developments and accelerated exploration plans,” said Steve Greenlee, president of ExxonMobil Exploration Company. “Development options for Hammerhead will take into account ongoing evaluation of reservoir data, including a well test.”

Low permeability coal seam gas productivity enhancement by cyclic nitrogen injection technique (an adsorption simulation study)

Coal seam gas (CSG) usually contains high levels of methane, which is mostly in the adsorbed state on micropores. For coal that is not highly permeable, stimulation may be required to enhance productivity. In this study, we propose a new technique to increase near wellbore productivity in tight CSG. This technique comprises three stages: injection, soaking and production. Firstly, nitrogen is introduced to the target formation while maintaining high reservoir pressure. Next, the well is shut for a period of time before the gases are flown back to the surface. The technique is based on competitive adsorption of methane and nitrogen during the shut-in period, which yields pressure build-up. Hence, with this combination of desorption, the coal matrix shrinks and permeability eventually increases. The proposed technique was tested by adsorption simulation at core scale. The model was constructed for crushed samples and the extended Langmuir isotherm and micro–macro kinetics models were applied in ASPEN adsorption software. Tight coal was then simulated with different porosity and sorption characteristics. Finally, we used the stress-sensitive permeability model Palmer–Mansoori to predict permeability changes. The results show that permeability is improved based on pressure variations. We observed 10% pressure increments with greater than 150% permeability enhancement. The model indicates the feasibility of the newly proposed technique to produce the ‘unproducible’. However, more experimental and simulation studies at a reservoir scale are needed to fully confirm the technique.