Characterization of pore structure in baode coals treated with saturated water and drilling fluid

DOI

10.2991/ifeesm-15.2015.172How to use a DOI?

Keywords

coal; drilling fluid; pore structure; nitrogen adsorption; mercury injection

Abstract

For further research on microscopic pore characteristics and its geological accumulation significance of coal bed, coal samples from drilling holes of Baode, Shanxi province in China were collected to perform scanning electron microscopy (SEM), mercury injection and low-temperature nitrogen sorption-desorption experiments. It is shown that intergranular pores and transitional pores are main types, accompanied by obvious oval shaped pores and friction pores in Baode coal, well-developed micro-cracks and micro-pores can be observed with less obstruction, permeability is good. The pores are mainly airtight with a close end or cylindrically connected, little ink-bottle pores are found, illustrating a strong tectonic stress on the coal. Dissolution pores dominate after immersion of the coal in the saturated water, leading to round surface covered by many particulate matters, as well as slightly decreased pore surface area and pore volume, accounting for dissolution of minerals into the saturated water. In presence of the saturated drilling fluid, pore area and pore volume corresponding to the above pore diameters decline greatly. Round surface with little coverage of particulate matters and majority of pores filled with particles can be identified, resulting in almost completely airtight pores with a close end, demonstrating drilling fluids adsorption to coal and blockage occurred. Large quantity of micro-pores and transitional pores are beneficial for gas adsorption in the coals. It is necessary to add appropriate plugging materials and proper amount of surfactants into the drilling fluids to seal cracks and pores in the coal, reducing drilling fluids invasion and destroy to side wall of drilling holes.

Copyright

© 2015, the Authors. Published by Atlantis Press.

Open Access

This is an open access article distributed under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).

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TY  - CONF
AU  - Fu-sheng Yang
AU  - Min-qun Lin
AU  - Ben-long Wei
AU  - An-ning Zhou
AU  - Hui-jun Zhang
AU  - Hao Wang
AU  - Yun-huan Jing
AU  - Lei Yang
AU  - Le-bo Ma
PY  - 2015/09
DA  - 2015/09
TI  - Characterization of pore structure in baode coals treated with saturated water and drilling fluid
BT  - Proceedings of the 2015 International Forum on Energy, Environment Science and Materials
PB  - Atlantis Press
SP  - 939
EP  - 942
SN  - 2352-5401
UR  - https://doi.org/10.2991/ifeesm-15.2015.172
DO  - 10.2991/ifeesm-15.2015.172
ID  - Yang2015/09
ER  -