  In subterranean coal seam gas CSG reservoirs, massive amounts of small-sized
coal fines are released during the production and development stages,
especially during hydraulic fracturing stimulation. These coal fines inevitably
cause mechanical pump failure and permeability damage due to aggregation and
subsequent pore throat blockage. This aggregation behavior is thus of key
importance in CSG production and needs to be minimized. Consequently, such coal
fines dispersions need to be stabilized, which can be achieved by the
formulation of improved fracturing fluids. Here, we thus systematically
investigated the effectiveness of two additives; ethanol, 0.5 wt percent and
SDBS, 0.001 and 0.01 wt percent, on dispersion stability for a wide range of
conditions: pH 6 to 11, salinity of 0.1 to 0.6 M NaCl brine. Technically, the
coal suspension flowed through a glass bead proppant pack, and fines retention
was measured. We found that even trace amounts of sodium dodecylbenzene
sulfonate SDBS i.e. 0.001 wt per cent drastically improved dispersion stability
and reduced fines retention. The retention was further quantified by fractal
dimensional analysis, which showed lower values for suspensions containing
SDBS. This research advances current CSG applications and thus contributes to
improved energy security.
