煤層氣(英語:coalbed methane)是指被吸附在煤層中的甲烷。因其不含硫化氫而被稱為“甜氣” [1] 。這種氣體在地下煤礦開採中時,會溢出造成安全風險。近幾十年來,從煤層中提取的天然氣已成為美國、加拿大、澳大利亞和其他國家的重要能源[2][3]

煤層氣與典型的砂岩或其他常規氣藏不同,因為煤層氣甲烷是吸附在煤層孔隙和裂縫中 [4]。煤層氣幾乎不含丙烷或丁烷等重碳氫化合物,而且不含天然氣凝析油。煤層氣是由乾酪根和其他有機質的熱裂解成熟而形成的[5] [6]。煤層氣中所含的氣體主要是甲烷和微量的乙烷、氮氣、二氧化碳和少量其他氣體。

煤層氣儲層被認為是雙孔隙儲層。其中天然裂縫是負責流動而基質的孔隙度是負責儲氣[5]

參考文獻

  1. ^ Moore, Tim A. (2012). "Coalbed methane: A review". International Journal of Coal Geology. 101: 36–81. doi:10.1016/j.coal.2012.05.011. ISSN 0166-5162.
  2. ^ US Energy Information Administration, Coalbed methane production, accessed 9 Oct. 2013
  3. ^ Geoscience Australia, Coal seam gas Archived 16 October 2013 at the Wayback Machine, accessed 10 Oct. 2013
  4. ^ McKee, C. R., Bumb, A. C., & Koenig, R. A. (1988, March 1). Stress-Dependent Permeability and Porosity of Coal and Other Geologic Formations. Society of Petroleum Engineers. doi:10.2118/12858-PA
  5. ^ 5.0 5.1 Laubach, S. E; Marrett, R. A; Olson, J. E; Scott, A. R (1 February 1998). "Characteristics and origins of coal cleat: A review". International Journal of Coal Geology. 35 (1): 175–207. doi:10.1016/S0166-5162(97)00012-8. ISSN 0166-5162
  6. ^ Saurabh, Suman; Harpalani, Satya (15 March 2018). "Modeling of microbial methane generation from coal and assessment of its impact on flow behavior". Fuel. 216: 274–283. doi:10.1016/j.fuel.2017.12.015. ISSN 0016-2361