Coal characterization and coalbed methane potential of the Chico-Lomã Coalfield, Paraná Basin, Brazil – Results from exploration borehole CBM001-CL-RS

The aim of this study was to determine the coal characteristics in the Chico-Lomã coalfield, Brazil and to evaluate the potential of natural gas associated with the coal seams (CBM), by carrying out a test well (CBM001-CL-RS) for collecting coal samples, followed by gas desorption measurements, and petrographical and chemical analyses of the coals and their methane adsorption capacities. The gas collected was analyzed for gas composition, stable carbon and hydrogen isotopes. The results indicate a cumulative coal thickness of 11.46 m in well CBM001-CL-RS, associated with an igneous intrusion of 10 m thickness. In the contact zone with the intrusion, the organic matter is severely altered with partial transformation of the coal to natural coke at distances less than 2 m from the intrusion. The ash content, based on proximate analysis, shows a variation from 29.1 to 82.8 wt.%. The sulphur content ranges from 0.43 to 3.89 wt.% and shows higher values in samples from the top of the Rio Bonito Formation. The gas desorption measurements range from 0.05 to 0.74 cm3/g, with methane being the predominant gas (>90%). A thermal origin of the gas is suggested by C and H isotopes and the C1 (methane) to C3 (propane) hydrocarbon distribution. The methane adsorption capacity of the samples varies from 2.50 to 6.50 cm3/g. Changes in microporosity related to thermal alteration may have a significant impact on the gas-holding capacity of samples located near the contact to the intrusion. For the study area, a 3D geological model was generated to estimate the volume of coal in the coalfield, followed by assessment of the gas volume associated with the coal. Based on the 3D model, a preliminary appraisal indicates resources of 7.2 billion tons of coal for the Chico-Lomã coalfield, associated with 2.7 billion m3 of gas.

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Characterisation of Surat Basin Walloon interburden and overlying Springbok Sandstone: a focus on methane adsorption isotherms, permeability and gas content

The APPEA Journal ◽

10.1071/aj19078 ◽

2020 ◽

Vol 60 (2) ◽

pp. 748

Author(s):

Syed Shabbar Raza ◽

Julie Pearce ◽

Pradeep Shukla ◽

Phil Hayes ◽

Victor Rudolph

Keyword(s):

Adsorption Isotherms ◽

Gas Adsorption ◽

Methane Adsorption ◽

Gas Content ◽

Coal Seams ◽

X Ray ◽

Gas Desorption ◽

Water Wells ◽

Temperature And Pressure ◽

Coal Measures

The Surat Basin in Queensland is one of the world’s premier producers of natural gas from coal seams. We investigate the potential for clay-rich Walloon Coal interburden and the overlying Springbok Sandstone to hold or produce gas. Seventeen core samples were analysed from two wells from intervals within the Walloon Upper Juandah Coal Measures interburden and the Springbok Sandstone. Samples were characterised using high-pressure methane adsorption isotherms, canister gas desorption tests, moisture contents, ash contents, carbon contents, scanning electron microscopy/energy dispersive X-ray spectrometry, X-ray quantitative clay analysis, permeability, helium pycnometry and mercury intrusion porosimetry. Methane adsorption was conducted at 30°C with up to 8 MPa pressure on dried crushed samples. The adsorption capacity of methane at 8 MPa varied from 3 cc/g (calcite-cemented) up to 25 cc/g (standard temperature and pressure equivalent) (coal). Clay-rich interburden samples adsorbed ~5–14 cc/g (dry). The measured isotherms and methane content from canister desorption tests show that appreciable volumes of gas are contained within some portions of interburden and in the overlying Springbok Sandstone. Gas within the interburden likely represents a large volumetric resource, albeit in low permeability rock that restricts direct productivity. The gas adsorption and gas content results for the Springbok Sandstone help to explain field observations of high gas content in some landholder water wells.

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Estimation of Coal Bed Methane Potential of Coal Seams of Margherita Coal Field, Assam, India

International Journal of Applied Sciences and Biotechnology ◽

10.3126/ijasbt.v3i2.12449 ◽

2015 ◽

Vol 3 (2) ◽

pp. 232-235

Author(s):

Prasenjit Talukdar ◽

Ranjan Das ◽

Rishiraj Goswami

Keyword(s):

Proximate Analysis ◽

Energy Resources ◽

Coal Bed ◽

Coal Bed Methane ◽

Coal Field ◽

Coal Seams ◽

Energy Needs ◽

Methane Potential ◽

Rapid Industrialization ◽

Great Stress

The rapid industrialization and growing energy needs have put a great stress on the conventional energy resources. This is even more concerning for a country like India which is a net importer of oil. To meet the ever increasing need for energy, it is essential that the search for unconventional energy is intensified. This paper deals with the estimation of coal bed methane potential of the Margherita Coal Field of Assam, India. For this purpose, eight coal samples were collected from Tirap O.C.P., Ledo UG Incline and Tikak O.C.P collieries of the Margherita coal field. Proximate analysis, megascopic study and finally qualitative analysis of these eight samples was undertaken. After analysis, the inferred reserves of CBM at Margherita Coalfield, was found to be in the range of 42.5-49.04 Billion Cubic Meter.Int J Appl Sci Biotechnol, Vol 3(2): 232-235DOI: http://dx.doi.org/10.3126/ijasbt.v3i2.12449

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A Comprehensive Coal Reservoir Classification Method Base on Permeability Dynamic Change and Its Application

Energies ◽

10.3390/en13030644 ◽

2020 ◽

Vol 13 (3) ◽

pp. 644 ◽

Cited By ~ 2

Author(s):

Xinlu Yan ◽

Songhang Zhang ◽

Shuheng Tang ◽

Zhongcheng Li ◽

Yongxiang Yi ◽

...

Keyword(s):

Coalbed Methane ◽

Dynamic Change ◽

Initial Permeability ◽

Gas Production ◽

Gas Desorption ◽

Reservoir Permeability ◽

Geological Conditions ◽

Production Stages ◽

Productivity Potential ◽

Coal Reservoir

Due to the unique adsorption and desorption characteristics of coal, coal reservoir permeability changes dynamically during coalbed methane (CBM) development. Coal reservoirs can be classified using a permeability dynamic characterization in different production stages. In the single-phase water flow stage, four demarcating pressures are defined based on the damage from the effective stress on reservoir permeability. Coal reservoirs are classified into vulnerable, alleviative, and invulnerable reservoirs. In the gas desorption stage, two demarcating pressures are used to quantitatively characterize the recovery properties of permeability based on the recovery effect of the matrix shrinkage on permeability, namely the rebound pressure (the pressure corresponding to the lowest permeability) and recovery pressure (the pressure when permeability returns to initial permeability). Coal reservoirs are further classified into recoverable and unrecoverable reservoirs. The physical properties and influencing factors of these demarcating pressures are analyzed. Twenty-six wells from the Shizhuangnan Block in the southern Qinshui Basin of China were examined as a case study, showing that there is a significant correspondence between coal reservoir types and CBM well gas production. This study is helpful for identifying geological conditions of coal reservoirs as well as the productivity potential of CBM wells.

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Comparison of two gas volume measurement systems by evaluating biochemical methane potential

Environmental Quality Management ◽

10.1002/tqem.21776 ◽

2021 ◽

Author(s):

Odorico Konrad ◽

Camila Hasan ◽

Munique Marder ◽

Lucas Zulian ◽

Marildo Guerini Filho

Keyword(s):

Volume Measurement ◽

Biochemical Methane Potential ◽

Measurement Systems ◽

Methane Potential ◽

Gas Volume

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Environmental Risk Related to the Exploration and Exploitation of Coalbed Methane

Energies ◽

10.3390/en13246537 ◽

2020 ◽

Vol 13 (24) ◽

pp. 6537

Author(s):

Barbara Uliasz-Misiak ◽

Jacek Misiak ◽

Joanna Lewandowska-Śmierzchalska ◽

Rafał Matuła

Keyword(s):

Coalbed Methane ◽

Environmental Risks ◽

Risk Category ◽

Burial History ◽

Exploration And Exploitation ◽

Coal Seams ◽

Mining Operations ◽

Environmental Threats ◽

And Migration ◽

Coal Macerals

In coal seams, depending on the composition of coal macerals, rank of coal, burial history, and migration of thermogenic and/or biogenic gas. In one ton of coal 1 to 25 m3 of methane can be accumulated. Accumulation of this gas is included in unconventional deposits. Exploitation of methane from coal seams is carried out with wells from mining excavations (during mining operations), wells drilled to abandoned coal mines, and wells from the surface to unexploited coal seams. Due to the low permeability of the coal matrix, hydraulic fracturing is also commonly used. Operations related to exploration (drilling works) and exploitation of methane from coal seams were analyzed. The preliminary analysis of the environmental threats associated with the exploration and exploitation of coalbed methane has made it possible to identify types of risks that affect the environment in various ways. The environmental risks were estimated as the product of the probability weightings of adverse events occurring and weightings of consequences. Drilling operations and coalbed methane (CBM) exploitation leads to environmental risks, for which the risk category falls within the controlled and accepted range.

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