Coal swelling strain and permeability change with injecting liquid/supercritical CO2 and N2 at stress-constrained conditions

Permeability evolution in fractured coal: The roles of fracture geometry and water-content

“…The relation between swelling strain and the amount or volume of gas sorbed is found to be either linear (Chikatamarla et al, 2004;Cui et al, 2007;Czerw, 2011;Levine, 1996;Robertson and Christiansen, 2005) or non-linear (Day et al, 2008;Kelemen and Kwiatek, 2009;Majewska et al, 2010). Coal swelling strain of wet coals is less than that of dry coals (Kiyama et al, 2011;Mazumder and Wolf, 2008;van Bergen et al, 2009), illustrating the effect of water on the swelling strain.…”

“…Previous studies have shown that coal swells when exposed to N 2 , CH 4 , and CO 2 , with volumetric strain ranging from 0.1% to 15%, under pressures up to 20 MPa and temperatures up to 55°C (Cui et al, 2007;Day et al, 2008;Harpalani and Schraufnagel, 1990;Karacan, 2007;Kiyama et al, 2011;Levine, 1996;Mazumder and Wolf, 2008;Robertson and Christiansen, 2005;Seidle and Huitt, 1995;Wang et al, 2010a,b). Coal swelling strain increases with increasing pore pressure and strain induced by CO 2 is commonly larger than that induced by CH 4 .…”

Optimizing enhanced coalbed methane recovery for unhindered production and CO2 injectivity

“…Coal swells with adsorption of CO 2 and develops compactive stresses if mechanically constrained (Day et al, 2010;Pone et al, 2010;Reucroft and Patel, 1986;Siemons and Busch, 2007). Coal swelling has been implicated as observed reductions in permeabilities during ECBM operations at pilot plant scale (Durucan and Shi, 2009;Kiyama et al, 2011;van Bergen et al, 2006). Gas adsorption and related swelling is largely impacted by sorption capacity, coal rank and the composition of the permeating gas (Chikatamarla et al, 2004a, b;Levine, 1996;Pone et al, 2010).…”

Effect of Coal Rank on Various Fluid Saturations Creating Mechanical Property Alterations Using Australian Coals

“…Hence, it is vital to identify how different types of coals behave under the effect of moisture. In the case of N 2 saturation, researchers [3,[20][21][22][23] have found that N 2 has the ability to recover CO 2 adsorption-induced coal matrix alteration, which eventually enhances the hydraulic properties of the coal matrix. Perera, Ranjith and Peter [24] have investigated the behavior of N 2 and CO 2 saturation on low-rank brown coal and observed around 2% increase in strength and Young's modulus for 3 MPa N 2 saturation.…”