Baranovskyi V.I., Kuznetsova L.D. Petrographic assessment of coal gas content

Details
Parent Category: Geo-Technical Mechanics, 2019
Category: Geo-Technical Mechanics, 2019, № 148

Geoteh. meh. 2019, 148, 13-19

https://doi.org/10.1051/e3sconf/201910900004

PETROGRAPHIC ASSESSMENT OF COAL GAS CONTENT

 1Baranovskyi V.I., 1Kuznetsova L.D.

1Institute of Geotechnical Mechanics named by N. Poljakov of National Academy of Sciences of Ukraine

 UDC 552.12.08:[553.981.4:553.94]

Language: English

Abstract.

Traces of the gas generation process on natural coal burstings have been identified and documented using the petrographic method. Their characteristic features were described. The methodology of their quantitative calculation is proposed in order to assess the modern gas content of coals. Two new indexes were proposed – the quantity of traces gas per 100 mcm2 and the degree of infestation of the gelified substance. In one coal bed, the quantity of traces gas is distributed unevenly both upon the thickness of the bed and along the strike. The mechanism of formation of "gas bubbles" can be explained from the point of view of the kinetic theory by Academician Ya.I. Frenkel. The quantity of traces gas per 100 mcm2 the coal surface Qc characterizes the properties of the gelified substance of coals, their gas-generating ability. The quantity and size of traces of the gas generation process depend on the degree of coalification, their size varies from micron fractions to 50 microns or more, and at the low coalification stages these are single large "traces", at medium stages both small and large traces, and in highly carbonized coals there are mostly small ones. In one coal bed, the quantity of traces gas is distributed unevenly both upon the thickness of the bed and along the strike "Traces of gas generation" do not disappear at the stage of gasless anthracites, although their quantity is somewhat reduced relative to anthracites, containing gas. Using a technique, similar to the method of calculating the petrographic composition in coals, a quantitative assessment of traces of gas generation was given and in the series from Lignite to low volatile Bituminous a direct dependence of their quantity on the values of modern gas content of coal beds was revealed. On the basis of photographic materials of coal-petrography research, the presence of a gas generation process in coals has been confirmed. The data obtained by the new method are well correlated with the known factual gas-bearing data obtained by traditional methods. The proposed method is not express and requires a certain qualification of the coal-petrographer.

 Keywords: traces of the gas generation process,petrographic method, gas content, quantitative calculation.

References

  1. Shulga V.F. (1981). Nizhnekarbonovaya uglenosnaya formatsiya Donetskogo basseyna. Moskva: Nauka
  2. Golubev A.A., Mayboroda A.A., Antsiferov V.A. and Kanin V.A. (2008). Genetic aspect of the generation of accumulations and fields of free hydrocarbon gases of the Greater Donets Basin. Naukovi pratsi UkrNDMI NAN Ukrainy, (3), pp.25-40
  3. Shulga V.F., Lukin A.Y. and Lelik B.I. (2000). Fossil indicators of gas emission in coal-bearing sediments of the Lviv-Volyn basin. Litologiya i poleznye iskopaemye, (5), pp. 554-560
  4. Baranovskiy V.I. (2010). Petrographic indicators of reactive carbons. Geotekhnicheskaya mekhanika: Mezhvedomstvennyy sbornik nauchnykh trudov. IGTM NAN Ukrainy, (88), pp. 271-275
  5. Bezruchko K.A. and Baranovskiy V.I. (2014). Marks of gas-generation processes in Donbas coal. Ugol Ukrainy, (11), 31
  6. GOST 9414.2-93 (ISО 7404/2-85). (1995). Methods for the petrographic analysis of bituminous coal and anthracite. Part 2. Method of preparing coal samples. Мoskva: Izdatelstvo standartov
  7. Computer program ImageJ. Retrieved from: http://rsb.info.nih.gov/ij/. html
  8. Frenkel, Ya.I. (1975). Kineticheskaya teoriya zhidkostey. Leningrad: Nauka

About the authors

Baranovskyi Volodimir Ignatovich, Junior Researcher of Geology of Coal Beds at Great Depths, Institute of Geotechnical Mechanics named by N. Poljakov of National Academy of Sciences of Ukraine (IGTM, NAS of Ukraine), Dnipro, Ukraine, This email address is being protected from spambots. You need JavaScript enabled to view it.

Kuznetsova Liubov Dmitrievna, Engineer of Geology of Coal Beds at Great Depths, Institute of Geotechnical Mechanics named by N. Poljakov of National Academy of Sciences of Ukraine (IGTM, NAS of Ukraine), Dnipro, Ukraine, This email address is being protected from spambots. You need JavaScript enabled to view it.