Quantitative Evaluation of Coal Seam Gas Content Estimate Accuracy

1995 ◽  
Author(s):  
Matthew J. Mavor ◽  
Timothy J. Pratt ◽  
Charles R. Nelson
Keyword(s):  
Coal Seam ◽  
Quantitative Evaluation ◽  
Gas Content ◽  
Coal Seam Gas

scholarly journals Nitrogen Injection To Flush Coal Seam Gas Out Of Coal: An Experimental Study

2015 ◽  
Vol 60 (4) ◽  
pp. 1013-1028 ◽  
Author(s):  
Lei Zhang ◽  
Naj Aziz ◽  
Ting Ren ◽  
Jan Nemcik ◽  
Shihao Tu
Keyword(s):  
Coal Seam ◽  
Clean Energy ◽  
Gas Content ◽  
Coal Seams ◽  
Coal Seam Gas ◽  
Gas Recovery ◽  
Nitrogen Injection ◽  
Gas Desorption ◽  
Effective Role ◽  
Study Laboratory

Abstract Several mines operating in the Bulli seam of the Sydney Basin in NSW, Australia are experiencing difficulties in reducing gas content within the available drainage lead time in various sections of the coal deposit. Increased density of drainage boreholes has proven to be ineffective, particularly in sections of the coal seam rich in CO2. Plus with the increasing worldwide concern on green house gas reduction and clean energy utilisation, significant attention is paid to develop a more practical and economical method of enhancing the gas recovery from coal seams. A technology based on N2 injection was proposed to flush the Coal Seam Gas (CSG) out of coal and enhance the gas drainage process. In this study, laboratory tests on CO2 and CH4 gas recovery from coal by N2 injection are described and results show that N2 flushing has a significant impact on the CO2 and CH4 desorption and removal from coal. During the flushing stage, it was found that N2 flushing plays a more effective role in reducing adsorbed CH4 than CO2. Comparatively, during the desorption stage, the study shows gas desorption after N2 flushing plays a more effective role in reducing adsorbed CO2 than CH4.

THE WALLOON COAL MEASURES—THE NEXT COAL SEAM GASTARGET?

2000 ◽  
Vol 40 (1) ◽  
pp. 86
Author(s):  
S.G. Scott ◽  
P. Crosdale
Keyword(s):  
Coal Seam ◽  
Vitrinite Reflectance ◽  
Petroleum Exploration ◽  
Gas Content ◽  
Coal Seam Gas ◽  
Gas Industry ◽  
Permian Coal ◽  
Petroleum Wells ◽  
The Individual ◽  
Coal Measures

The Queensland coal seam gas industry has grown over the last 12 years. During this time the vast majority of exploration wells have targeted the Late Permian coal measures in the Bowen and Galilee Basins. These formations have been the major target because they contain coals with a vitrinite reflectance ranging above 0.7%. This range has always been seen as the main period for methane generation.As well as containing vast quantities of Permian coal, Queensland also has vast quantities of Middle Jurassic coals within its Mesozoic Basins. These coals have received little-to-no exploration for their coal seam gas potential as they have always been interpreted as being immature for gas generation.Over 550 petroleum exploration wells drilled in the Mesozoic Surat Basin of eastern Queensland were reviewed to determine the coal volume of the intersected Walloon Coal Measures. A significant number have intersected large volumes of sub-bituminous to high volatile bituminous coals, in seams ranging up to 11.7 m in thickness. While the individual seams are not laterally persistent, the coal packages can be traced over hundreds of kilometres of the eastern Surat Basin.While only one well has tested the gas content, gas quality and saturation of the Walloon Coal Measures, numerous water bores have reported gas flows from the zone, and petroleum wells intersecting the formation have recorded high mud gas readings during drilling.The relatively shallow depth of the unit over much of the basin, the thickness of the coal packages, the proximity to major gas trunk pipelines and markets make the Walloon Coal Measures an ideal target for the next generation of coal seam gas explorers.

A Study on the Occurrence Law of Coal Seam Gas in Shanxi

2012 ◽  
Vol 594-597 ◽  
pp. 2244-2250 ◽  
Author(s):  
Guang Wu Xue ◽  
Hong Fu Liu ◽  
Jing Lin Guo
Keyword(s):  
Coal Seam ◽  
Mining Area ◽  
Magmatic Rock ◽  
Gas Content ◽  
Control Factor ◽  
Coal Seam Gas ◽  
Qinshui Basin ◽  
Mining Areas ◽  
Control Factors ◽  
Open Structures

The thickness of overlaying bedrock is the main control factor of preservation, in addition, magmatic activities, different structural types and hydrogeological conditions are also control factors. Regional magmatic thermometamorphism appeared as a kind of superimposed effect on the background of deep metamorphism. Two Eastwest （EW）metamorphic belts in Shanxi tallied with the distribution of magmatic rock masses, resulting in coal seam gas exploitation and utilization bases of Yangquan and Jincheng mining areas. From gas-accumulation structural setting, closed type structures make high gas content in coal reservoir such as Qinnan, Gujiao, Xingjiashe, Dongshe areas in the Qinshui Basin, Shilou, Daning-Jixian and Sanjiao-Liulin areas in the Hedong Basin, gas content is 10-15 m³/t or even higher. There are convenient channels for coal seam gas effusion in the open structures; with lower gas content, such as Lishi mining area in Hedong Basin, Huoxi structural area in Qinshui Basin, Hunyuan, and Wutai coal districts.

scholarly journals Analisis Model Kecepatan Gelombang-P pada Coal-Seam Gas Studi Kasus Cekungan Sumatera Selatan, Indonesia

2020 ◽  
Vol 6 (2) ◽  
pp. 113-120
Author(s):  
Harnanti Yogaputri Hutami ◽  
Fitriyani Fitriyani ◽  
Tiara Larasati Priniarti ◽  
Handoyo Handoyo
Keyword(s):  
Coal Seam ◽  
Elastic Properties ◽  
Wave Velocity ◽  
Rock Physics ◽  
Velocity Model ◽  
Significant Negative Correlation ◽  
P Wave ◽  
Gas Content ◽  
Coal Seam Gas ◽  
P Wave Velocity

The rock physics model is one effective yet challenging way to investigate the coal-seam gas potential in Indonesia. However, because of the complex conditions of the Coal-Seam Gas Reservoirs, it is difficult to establish models. Despite the scarce modeling, this study aims to estimate the relation of gas-saturated within pores of coal seam to the elastic properties of rock, which is P-wave velocity. First, the coal seam minerals are applied to quantify matrix moduli using the Voigt-Reuss-Hill Average method. Pride’s simple equation is used to estimate the elastic properties of the coal seam at dry condition (zero gas saturation). Finally, Biot-Gassmann’s theory is applied to determine the elastic properties of coal seam with fully gas saturated. As the result, the proposed model showed that there is a significant negative correlation between gas content with both density and P-wave velocity of the coal seam. Finally, this P-wave velocity model of gas-saturated coal seams should be properly useful as the quick look for identifying coal seam gas potentials. 

The Walloon coal seam gas play, Surat Basin, Queensland

2012 ◽  
Vol 52 (1) ◽  
pp. 273 ◽  
Author(s):  
Damien Ryan ◽  
Andrew Hall ◽  
Leon Erriah ◽  
Paul Wilson
Keyword(s):  
Coal Seam ◽  
Structural Features ◽  
Low Rank ◽  
Gas Content ◽  
Fracture Permeability ◽  
Coal Seam Gas ◽  
Reservoir Properties ◽  
Tectonic History ◽  
World Class ◽  
Compositional Variability

Extensive drilling of the Walloon Subgroup for coal seam gas (CSG) during the last decade has revealed a world-class CSG play on the northern flank of the Surat Basin. Resources discovered in the Walloon Subgroup exceed 30 TCF; this gas now underpins four CSG-to-liquefied natural gas (LNG) projects. Results to date have revealed the highly heterogeneous nature of the Walloon Subgroup and its associated coal properties. The Walloon Subgroup is typically 350 m thick and contains an average of 30 m of net coal that is interbedded with a range of clay-rich, fluvio-lacustrine lithologies. The most prospective area of the play occurs down-dip and adjacent to the Walloon subcrop edge, where high permeability exists combined with a thick section of net pay. Coals in the Walloon Subgroup are low rank (0.35–0.65% Ro) with gas contents ranging between 1–15 m3/tonne (dry ash-free). Average coal ply thickness is 30 cm, making correlation and prediction of reservoir properties difficult. Reservoir properties—including permeability, gas content and saturation—differ as a result of compositional variability of the coal seams and also the tectonic history. Mapping of sparse 2D seismic data has highlighted the distribution of major structural features throughout the basin. Coal fracture permeability ranges from less than 0.1 mD to more than 2,000 mD, and mapping has identified areas where permeability appears to be enhanced on structures that have undergone mid Cretaceous–Eocene deformation.

Impact of in-seam drilling performance on coal seam gas production and remaining gas distribution

2019 ◽  
Vol 59 (1) ◽  
pp. 328
Author(s):  
Fengde Zhou ◽  
Glen Fernandes ◽  
Joao Luft ◽  
Kai Ma ◽  
Mahmoud Oraby ◽  
...  
Keyword(s):  
Coal Seam ◽  
Gas Production ◽  
Gas Content ◽  
Gas Distribution ◽  
Coal Seams ◽  
Coal Seam Gas ◽  
Gas Saturation ◽  
Drilling Performance ◽  
Permeability Anisotropy ◽  
The Impact

Drilling horizontal wells in low permeability coal seams is a key technology to increase the drainage area of a well, and hence, decrease costs. It’s unavoidable that some parts of the horizontal section will be drilled outside the targeted coal seam due to unforeseen subsurface conditions, such as sub-seismic faulting, seam rolls, basic geosteering tools, drilling practices and limited experiences. Therefore, understanding the impact of horizontal in-seam drilling performance on coal seam gas (CSG) production and remaining gas distribution is an important consideration in drilling and field development plans. This study presents a new workflow to investigate the impact of horizontal in-seam performance on CSG production and gas distribution for coal seams with different porosity, permeability, permeability anisotropy, initial gas content (GC), initial gas saturation and the ratio of in-coal length to in-seam length (RIIL). First, a box model with an area of 2 km × 0.3 km × 6 m was used for conceptual simulations. Reduction indexes of the cumulative gas production at the end of 10 years of simulations were compared. Then, a current Chevron well consisting of a vertical well and two lateral wells, was selected as a case study in which the impact of outside coal drilling on history matching and remaining gas distribution were analysed. Results show that the RIIL plays an increasing role for cases with decreasing permeability or initial gas saturation, while it plays a very similar role for cases with varied porosity, permeability anisotropy and GC. The size and location of outside coal drilling will affect the CSG production and remaining gas distribution.

A new method for accurate and rapid measurement of underground coal seam gas content

2015 ◽  
Vol 26 ◽  
pp. 1388-1398 ◽  
Author(s):  
Liang Wang ◽  
Long-biao Cheng ◽  
Yuan-ping Cheng ◽  
Shimin Liu ◽  
Pin-kun Guo ◽  
...  
Keyword(s):  
Coal Seam ◽  
New Method ◽  
Gas Content ◽  
Coal Seam Gas ◽  
Rapid Measurement

Gas Geology Law and Gas Forecast in Yongju Well Field

2011 ◽  
Vol 361-363 ◽  
pp. 208-211
Author(s):  
Cui Jia ◽  
Yu Lin Wang ◽  
Xu Yang ◽  
Mi Shan Zhong ◽  
Nan Yan
Keyword(s):  
Coal Seam ◽  
Geological Structure ◽  
Measured Data ◽  
Gas Content ◽  
Coal Seam Gas ◽  
Production Safety ◽  
Geological Conditions ◽  
Well Field ◽  
Gas Occurrence ◽  
The Relationship

This paper takes gas as a geological-mass to study, using gas geology theory, by analysising the geological conditions of Yongju mine in ShanXi, combining with the coal seam gas content data which measured underground to study the relationship between geological conditions and gas occurrence, reveal the gas occurrence factors: geological structure, roof and floor lithologic of coal seam, buried depth of coal seam and thickness of coal seam. Finally, using the measured data of gas content and gush, regression analysis, the gas gush is forecasted, playing a guiding role in the gas control and production safety .

COAL SEAM GAS IN THE SOUTHERN SYDNEY BASIN, NEW SOUTH WALES

1997 ◽  
Vol 37 (1) ◽  
pp. 415 ◽  
Author(s):  
M.M. Faiz ◽  
A.C. Hutton
Keyword(s):  
Coal Seam ◽  
New South ◽  
Geological Structure ◽  
Gas Content ◽  
Gas Composition ◽  
Late Permian ◽  
Coal Seams ◽  
Coal Seam Gas ◽  
South Wales ◽  
Coal Measures

The coal seam gas content of the Late Permian Illawarra Coal Measures ranges from Methane that occurs within the basin was mainly derived as a by-product of coalification. Most of the CO2 was derived from intermittent magmatic activity between the Triassic and the Tertiary. This gas has subsequently migrated, mainly in solution, towards structural highs and accumulated in anticlines and near sealed faults.The total desorbable gas content of the coal seams is mainly related to depth, gas composition and geological structure. At depths

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