Identification of Coal Petrologic-Structure by Using Geophysical Logging Data: A Case Study of the Coals of Hancheng Coalbed Methane Field

Abstract:

Coal petrologic structure is important for the prediction of coal and the associated coalbed methane outburst during coal mining. This paper discusses the relationship between the response characteristics of natural gamma (GR), laterlog deep (LLD) and compensation density curve (RHOB), and the coal structures. Results show that the tectonic-coals (the coals with high breakage degree by tectonic structures) can be identified by the logging characteristics of low amplitude of GR (20-90 API), high amplitude of LLD (300-1800 Ωm), and low amplitude of RHOB (1.25-1.5g/cm³). It was found that with increasing degree of the breakage, coal pores and fractures become well developed, and thus reduce the bulk density of coal and the content of radioelement but more gas within the coal. This is the reason for logging performances of low amplitude of GR and RHOB, as well as high amplitude of LLD for the tectonic-coals.

• Periodical: Applied Mechanics and Materials (Volumes 316-317)
• Pages: 795-798
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.316-317.795
• Online since: April 2013
• Authors: Juan Teng, Yan Bin Yao, Da Meng Liu, Zhi Qiang Liu, Bei Liu
• Keywords: Coal Structure, Log Response, Microscopic Explanation, Original Coal, Tectonic Coal

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