Coal Wettability after CO2 Injection

Curtin University, Department of Exploration Geophysics, Kensington, Australia. *email address of corresponding author: [email protected]...
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Coal Wettability after CO2 Injection Ahmed Zarzor Al-Yaseri, Hamid Roshan, Xiaomeng Xu, Yihuai Zhang, Mohammad Sarmadivaleh, Maxim Lebedev, Ahmed Barifcani, and Stefan Iglauer Energy Fuels, Just Accepted Manuscript • DOI: 10.1021/acs.energyfuels.7b01189 • Publication Date (Web): 20 Oct 2017 Downloaded from http://pubs.acs.org on October 21, 2017

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Coal Wettability after CO2 Injection

A. Z. Al-Yaseri1*, H.Roshan2, X. Xu3, Yihuai Zhang1, M. Sarmadivaleh1, M. Lebedev4, A. Barifcani1and S. Iglauer1

1

Curtin University, Department of Petroleum Engineering, Kensington, Australia

2

School of Petroleum Engineering, University of New South Wales, Sydney, Australia

3

China University of Mining and Technology, Beijing, China

4

Curtin University, Department of Exploration Geophysics, Kensington, Australia

*email address of corresponding author: [email protected]

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Abstract Increasing energy demand and associated global warming are unarguably the two major challenges that the world currently faces. One of the ideas to reduce the carbon footprint while increasing the efficiency of the energy extraction is the CO2 sequestration in coal seams. This can additionally enhance the coal bed methane production. However, this process depends on many factors, among which coal wettability is of particular importance especially because of its pressure and temperature dependency. In order to evaluate this process, coal wettability was tested by measuring the contact angle of CO2/water as a function of pressure, temperature and salinity (DI water and brine (5 wt% NaCl + 1 wt% KCl) i.e. wt% is the weight percentage of salt to water. The results show that the CO2/water contact angle increases significantly with increasing pressure, temperature and salinity indicating more effective CO2 wetness of coal. This in turn can reduce the CO2 residual trapping capacities and increase methane recovery. Furthermore, we demonstrated that CO2 density correlates well with coal wettability.

Keywords: Wettability, Coal, Contact angle, CO2 storage, CBM, ECBM

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1. Introduction Recently CO2 emission has been recognized as a major cause of climate change. Emissions are

continuously

increasing

due

to

increased

energy

demand

as

global

industrialisation proceeds. Such increase in energy demand has given rise to the fossil fuel consumption and hence generation of CO2 [1]. CO2 geo-sequestration (CGS) has therefore attracted a considerable attention as a potential solution for increased CO2 emission [2, 3, 4, 5, 6, 7, 8]. It is however important to understand the nature of interaction between the fluid and the formation in order to safely store CO2 underground [9]. CGS is an efficient method to reduce these emissions, while enhancing oil and gas recovery in unconventional petroleum reservoirs [1, 10, 11] i.e. unmineable coal seams for CO2 trapping and enhanced coal bed methane (ECBM)

production [12,13,14,15,16]. As an

example, Reznik et al. [17] conducted an extensive laboratory study and showed that only 30–50% of the original methane in coal bed methane (CBM) can be recovered by natural desorption whereas the CO2 adsorption with pressure of 5.5 MPa can completely replace the methane and leads to 100% desorption of in situ methane. Therefore, CO2 sequestration in coal is a potential mechanism to maximize the commercial production from these reserves [18]; however, ECMB recovery by CO2 sequestration involves complex processes that are not yet fully understood [18]. Wettability is the ability of a fluid to maintain contact with a solid surface that can be measured through contact angle of the fluid with the solid phase [19]. Furthermore, wettability is directly related to the recovery efficiency and injection pressure design of CO2 sequestration projects [13, 16]. In addition, there are many other phenomena affecting the efficiency of ECBM. For instance, CO2 occupies relatively small micro-pores of the coal matrix after injection while brine stays in the larger pores [13]. CO2 wettability of coal is also

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higher than methane [20] but the CO2 leads to coal swelling, and fracturing of minerals [21], which can create the residual permeability. In addition, CO2 storage in coalbeds for ECBM is significantly different from the conventional reservoirs (CO2 can be dissolved in water or oil), because coalbeds act as both reservoir and source rock [22]. As mentioned, the CO2/coal/brine wettability is a particular factor in ECBM, especially due to high amount of water produced from most of the CBM wells [23,24] with salt concentration varying from 200 mg/L to 170,000 mg/L [25]. Such wettability is mainly a function of pressure, temperature, coal rank, and brine salinity [13,26,27]. It has been widely reported in the literature that the CO2 wettability in water/coal [13,26,27] and water/minerals [28,29,30,31,32,33,34] systems increases with increasing pressure. Kaveh et al. [27] showed that at a certain pressure a sudden increase in CO2 density is experienced where the excess sorption (both surface and capillary adsorption) is in fact reducing and surprisingly the contact angle linearly increases. Moreover, the sorption behaviour of CH4 and CO2 in coal was investigated by Hu et al. [35] based on molecular dynamic simulation and their results showed that coals adsorb more CO2 than CH4. The effect of temperature and brine salinity at different pressures however have not yet been entirely investigated for CO2/water/coal system; which is especially important where temperatures and brine salinities can vary significantly in subsurface formations[36]. Especially it has been shown that temperature and salinity have significant effects on CO2quartz [30,31,32,37], shale [9, 34] and Mica [33] wettabilities. In addition, the depth of the coalbeds varies from outcrop to more than 4000 m with average pressure gradient of 0.01027 MPa/m [38]. However, it is preferred to store the CO2 at temperatures and pressures above its critical point (304 K, 7.38 MPa) where CO2 absorption into coal is relatively high [39, 40].

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Therefore we measured the advancing and receding water contact angles of CO2–brine on a coal substrate at different pressures (0.1, 5, 10, 15, 20 MPa), temperatures (308, 323, and 343 K), and salinities (DI water and brine (5 wt% NaCl + 1 wt% KCl)). The results were then analysed with a newly proposed physical model [32, 34] derived based on the sharp-kink approximation [41, 42].

2. Experimental methodology The coal sample used in this study was extracted from a proposed storage site in Pingdingshan Ten colliery, Henan Province of China. There are three groups of coal seams at this site, a) Ding, Ji and Wu Groups: the gas pressure of Ding group varies from 0.6 MPa to 2.16 MPa corresponding to the depth of 400 m to 800 m, b) Ji group with pressure ranging from 0.5 MPa to 2.55 MPa corresponding to the depth of 430 m to 800 m and c) Wu group having pressure between 0.67 MPa to 2.45 MPa. The sample used in this study is collected from the Ding group with the average depth of 750 m, 1.6 to 2.3 m thickness and 14 m3/t gas content with the maximum gas pressure of 1.14 MPa. The block was then processed into coal powder, cylinder core and sub-blocks to conduct different measurements. Coal powder was used for proximate analysis (following China National Standards [43]) and to determine the coal rank [44]. Details of the tested coal sample are summarized in Table 1 with fixed carbon content up to 53.22% and volatile matter content as 36.43% (the tested coal is a typical sub-bituminous coal rank). Moreover, the zeta potential of the tested coal sample suspended in brine (5 wt% NaCl + 1 wt% KCl) was measured with a zeta potentiometer (Brookhaven ZetaPALS) at ambient conditions (298K and 0.1MPa), Table 2 i.e. zeta potential measurements were carried out with sample powder

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at a constant pH. All zeta potential were measured three times to take into the account the possible scatter of the data.

Table 1, Physical properties of the tested coal Ρ (g/cm3)

Mad (%)

Vdaf(%)

Aad(%)

Cf (%)

1.35

6.53

36.43

3.82

53.22

ρ, bulk density (with pores); Mad, moisture content (%Vol, air dry base); Vdaf, volatile matter (%, dry ash free); Aad, ash yield (%, air dry base); Cf, fixed carbon content.

Table 2, Zeta potentials (ZP) measured for the coal sample Sample No.

T

ZP

(K)

(mV)

1

298.15

-6.7

2

298.15

-9.15

3

298.05

-5.55

average

298.12

-7.13

standard deviation

0.0408

1.838

The intact coal substrate sample used for the contact angle measurement has a surface roughness of 1.1µm (RMS roughness measured with an atomic force microscopy instrument, model DSE 95-200). The surface roughness was used to correct the measured contact angles for roughness induced changes (REF) thus reproducibility of the results (Figure 1) [45]. It has been reported that a higher surface roughness resulted in lower advancing and receding contact angles [32,46]. 6 ACS Paragon Plus Environment

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Before

110 µm

(a)

(b)

After

(c)

63µm

(d)

Figure 1. Atomic force microscopy topography images of the coal surface used in the experiments (before and after testing), (a) and (c) deflection signal, different heights are colour coated before and after measurement; (b) and (d) 3D topography of the substrate. RMS roughness is 1.1 µm before and 1.3 µm after measurement.

In addition, the scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM) and x-ray micro-computed tomography (µCT) was used to select a region of the sample with lowest amount of micro-fractures in order to ensure that the droplet is not affected by unnecessary seepage into the sample (Figure 2).

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a

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coal

fracture

10 μm

EHT=15KV

b

Aperture size=30 μm

fracture fracture

coal

1mm Figure 2. a) SEM image of the coal sample, b) Raw Two-dimensional µCT image of the coal sample at 3.4 µCT.

The sample was cleaned by removing any surface contaminations before each test by exposing it to air plasma for 5min [47, 48, 49, 50].The substrate was then placed in a high pressure high temperature cell. The cell was pressurized with CO2 using a high precision syringe pump (ISCO 500D; pressure accuracy of 0.1% FS) until a pre-set value was obtained (Figure 3). When the desired pressure was attained, a droplet (average volume ∼ 7µL) of de-

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gassed brine (5 wt% NaCl + 1 wt% KCl) or deionized (DI) water (vacuumed for more than 10 hours) was dispensed onto the tilted substrate (tilting angle 12o) and advancing and receding contact angles were measured simultaneously [32] using a high definition video camera (Basler scA 640–70 fm, pixel size = 7.4 µm; frame rate = 71 fps; Fujinon CCTV lens: HF35HA-1B; 1:1.6/ 35 mm).This procedure was repeated for different pressures (0.1, 5, 10, 15, and 20MPa) and temperatures (308, 323, and 343K). It should be noted that brine was saturated with CO2 using a mixing reactor [51] although the earlier studies showed that the contact angle is not influenced by such equilibration [7].

Θ at 308 K and 5 MPa

Θ at 323 K and 10 MPa

0.75mm

0.75mm

Figure 3. Schematic diagram of the high temperature/high pressure contact angle measurement apparatus used for contact angle measurements.

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Results and discussion From zeta potential measurements on coal sample, an average surface potential of -7.13 mV at average pH of 8.3 was obtained [52,53]. Interestingly the coal surface had a slightly negative charge. It is known that surface charges can influence the contact angle and other rock properties [54,55,56] however; Roshan et al. [34] showed that such influence on contact angle can be only significant if the negative potential of the sample surface is below -10 mV. We therefore use the equation proposed by Al-Yaseri et al. [32] for neutral substrates where the liquid contact angle is related to density of gas phase in the system [57,58,59].

cosθ =

∆ρ

γ lg

I −1

(1)

The expansion of equation 1 gives:

cosθ = −

I

γ lg

ρg + (

I

γ lg

ρlf − 1)

(2)

Where θ is the contact angle of the liquid, γ lg is the interfacial tension between fluid phases I = −∫

∞ zmin

V ( z ) dz , is the van der Waals potential integral [42, 57, 58], and ∆ρ = ρlf − ρ g ( ρ g

is the gas density and ρlf is the film liquid density which is a function of the liquid and gas densities for a specific substrate [47]. The advancing and receding contact angles are presented in Figures 4 and 5, respectively where both advancing and receding contact angle significantly increased with increasing pressure for brine + CO2 and DI water + CO2 systems i.e. this is well consistent with literature data [13,26,27]. For instance, the advancing contact angle of brine at 343.15 K increased from 75 ° to 152 ° when the pressure increased from 0.1 to 20 MPa (Figure 4).

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Figure 4. Advancing and receding water contact angles for CO2/Brine as a function of pressure and temperature, RMS= 1.1µm.

Furthermore, temperature had a considerable effect on the contact angle, the contact angle increased for all pressures with an increase in temperature. This is consistent with most literature data on quartz, mica and carbonate substrates [31,32,60,61]; however, there are other studies showing that the contact angle can decrease with temperature [33,37,62].

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In order to analyse the results, equation 1 was therefore used. The measured advancingreceding water contact angles (Figures 4 and 5) were combined to obtain the Young’s contact angle e.g. equation 2 [63,64].

Figure 5. Advancing and receding water contact angles for CO2/DI water as a function of pressure and temperature, RMS= 1.1µm.

 rA cosθ A + rR cosθR   rA + rR  

θl = arccos 

(2)

With

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1/3

1/3

    sin3 θ A sin3 θR rA =  r =  and R   3 3  2 − 3cosθ A + cos θ A   2 − 3cosθR + cos θR 

The obtained contact angles were then plotted vs the CO2 density for both Brine + CO2 and DI water + CO2 systems (Figure 6). As seen from this figure, the contact angle of brine + CO2 and DI water+CO2 systems follow a well-defined linear correlation for each specific temperature (296, 323 and 343 K) e.g. three lines approach unity. The slope and intersect of each linear relationship along with its coefficient of determination (R2) are reported in Table 3.

Table 3. The slope, intersect and R2 of each fitted line (Eq. 1) to the experimental data of contact angle vs CO2 density at different temperatures. -

Brine+CO2

-

DI water+CO2

-

Temperature (K)

slope

intersect

R2

slope

intersect

R2

296

-0.001

0.391

0.97

-0.001

0.814

0.98

323

-0.0012

0.235

0.98

-0.0014

0.721

0.92

343

-0.0015

0.127

0.91

-0.0019

0.641

0.97

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Figure 6. Water contact angles vs CO2 density fitted with a linear equation (Eq.1) for CO2/Brine and CO2/DI water systems. The slope and intersect of each linear relationship is reported in Table 1.

It is seen from Figure 6 that the higher the density of CO2 (because of the increase in pressure), the higher the contact angle obtained. Looking at equation 1, it is seen that an increase in pressure significantly reduces ∆ρ and to some extent γ lg however the ∆ρ pressure dependency is more pronounced [65]. The ratio of

∆ρ

γ lg

therefore reduces with

pressure thus increasing contact angles e.g ρ lf variation with pressure is insignificant 14 ACS Paragon Plus Environment

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whereas

ρg

considerably

increases

with

pressure

increase

thus

reducing

∆ ρ ( = ρ lf − ρ g ) . On the other hand, the contact angle increases with temperature for brine+CO2 and DI water+CO2 systems. It is also observed from Eq. (1 or 2) that ∆ρ , γ lg and I are temperature dependent. It has been documented that the increase in temperature increases both the gasliquid interfacial tension and density difference between fluid phases especially at relatively higher pressure (≥ 5 MPa). However, the sensitivity of density difference to temperature is much more pronounced than the gas-liquid interfacial tension [31,65]. Therefore the ratio of

∆ρ

γ lg

will increase with increase in temperature which in turn reduces the contact angle

consistently. However, the increase in contact angle with temperature was seen from the results. Al-Yaseri et al [66] investigated the effect of temperature on van der Waals forces and showed that the increase in contact angle with temperature is related to decrease in van der Waals forces. In addition, the contact angles are consistently higher for brine than DI water for all pressures and temperatures (Figures 4 and 5) consistent with literature data for quartz and mica [32,33, 37,60.67]. Salinity can affect the density difference, interfacial tension between fluids and van der Waals potentials. The effect of salinity on interfacial tension is more significant than the effect of salinity on the density difference while such effect on van der Waals potentials is not yet fully understood. If assumed that the van der Waals potentials are unaffected by salinity, the increase in salinity increases the interfacial tension between CO2 and brine (> ) causing the contact angle to increase (equation 1).

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I

γ lg

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3. Conclusion We systematically measured advancing and receding water contact angles of the system brine (5 wt% NaCl + 1 wt% KCl as well as Deionised water), coal and CO2 at different pressure (0.1, 5, 10, 15, and 20 MPa) and temperature (296, 323 and 343 K) conditions. The results show that the contact angle of brine is higher than DI water and the contact angle of both increased with increasing pressure or temperature. Consequently, coal becomes increasingly CO2-wet with increasing pressure (CO2 density) which increases the seepage rate of CO2 into the coal. Moreover, CO2 wets the coal surface at high pressure and temperature more significantly leading to more efficient recovery of methane e.g. mainly due to wider distribution of CO2 in micro-pores and higher CO2 adsorption. It has been also shown that CO2 density can be used to estimate the water-CO2 contact angle on coal.

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References 1-B. Metz, O. Davidson, H.D. Coninck, M. Loos, L. Meyer, 2005. Carbon Dioxide Capture and Storage.IPCC, pp. 431. 2- P. Zweigel, R. Arts, A.E. Lothe, , E.B.G. Lindeberg, 2004. Reservoir geology of the Utsira Formation at the first industrial-scale underground CO2 storage site (Sleipner area, North Sea). Geological Society, London, (2004), pp. 165–180. 3- A. Chadwick, R. Arts, C. Bernstone, F. May, S. Thibeau, P. Zweigel, 2007. Best Practice for the Storage of CO2 in Saline Aquifers-Observations and Guidelines from the SACS and CO2 STORE Projects. British Geological Survey, Nottingham, 4, pp.267. 4- R.J. Arts, A. Chadwick, O. Eiken, S. Thibeau, S. Nooner, 2008. Ten years of experience with CO2 injection in the Utsira Sand at Sleipner (offshore Norway). First Break 26, 65–72. 5- L. André, M. Azaroual, A. Menjoz, 2010.Numerical simulations of the thermal impact of supercritical CO2 injection on chemical reactivity in a carbonate saline reservoir.Transport in Porous Media, 82, 247–274. 6-S. Brunsting, M.d. Best-Waldhober, C. F. J. Feenstra, and T. Mikunda, 2011. Stakeholder participation practices and onshore CCS: Lessons from the dutch CCS case barendrecht. Energy Procedia, 4, 6376–6383. 7-A. Al-Yaseri, M. Sarmadivaleh, A. Saeedi, M. Lebedev, A. Barifcani and S. Iglauer, 2015.N2+CO2+NaCl brine interfacial tensions and contact angles on quartz at CO2 storage site conditions in the Gippsland basin, Victoria/Australia. Journal of Petroleum Science and Engineering, 129(0), 58-62. 8-S. Iglauer, C.H. Pentland, and A. Busch, 2015.CO2 wettability of seal and reservoir rocks and the implications for carbon geo-sequestration. Water Resources Research, 51(1), 729774. 9-S. Iglauer, A. Al-Yaseri, R. Rezaee, and M. Lebedev, 2015. CO2-wettability of caprocks: Implications for structural storage capacity and containment security. Geophysical Research Letters, 42, 1-6. 10-S Iglauer, A. Paluszny, MJ Blunt, 2013. Simultaneous oil recovery and residual gas storage: a pore-level analysis using in-situ micro-tomography. Fuel, 103, 905-914. 11-T. Rahman, M. Lebedev, A. Barifcani and S. Iglauer, 2016of supercritical CO2 in oil-wet sandstone. Journal of colloid and interface science, 469, pp.63-68.

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12-F.V Bergen, H. Pagnier, P. Krzystolik, 2006. Field experiment of enhanced coalbed methane–CO2 in the upper Silesian basin of Poland Environmental Geosciences, 13, 201–224. 13-N. Siemons, H. Bruining, H. Castelijns, K.H. Wolf, 2006. Pressure dependence of the contact angle in a CO2–H2O–coal system. Journal of Colloid and Interface Science, 297, 755– 761. 14-F.V Bergen, P. Krzystolik, N.V. Wageningen, H. Pagnier, B. Jura, J. Skiba, P. Winthaegen, Z. Kobiela, 2009. Production of gas from coal seams in the Upper SilesianCoal Basin in Poland in the post-injection period of an ECBM pilot site International Journal of Coal Geology, 77, 175–187. 15-M. Mazzotti, R. Pini, G. Storti, 2009. Enhanced coalbed methane recovery. Journal of Supercritical Fluids, 47, 619–627. 16-N.S. Kaveh, E.S.J. Rudolph, K.H.A. Wolf and S.N. Ashrafizadeh, 2011. Wettability determination by contact angle measurements: hvBb coal–water system with injection of synthetic flue gas and CO2. Journal of colloid and interface science, 364(1), 237-247.

17-A.A. Reznik, P.K. Singh, W.L. Foley, 1984. An analysis of the effect of CO2 injection on the recovery of in-situ methane from bituminous coal: an experimental simulation. SPE Journal, 24, 521–528. 18-G.G Wang, X. Zhang, X. Wei, X. Fu, B. Jiang, and Y. Qin, 2011. A review on transport of coal seam gas and its impact on coalbed methane recovery. Frontiers of Chemical Science and Engineering, 5(2), 139-161. 19- Young, T. (1805), An essay on the cohesion of fluids, Philos. Trans. R. Soc. London, 95, 65–87. 20-Saghafi, A., Javanmard, H. and Pinetown, K., 2014. Study of coal gas wettability for CO2 storage and CH4 recovery.Geofluids, 14(3), pp.310-325. 21-Zhang, Y., Lebedev, M., Sarmadivaleh, M., Barifcani, A. and Iglauer, S., 2016. Swelling‐ induced changes in coal microstructure due to supercritical CO2 injection. Geophysical Research Letters, 43(17), pp.9077-9083. 22-J. Q.Shi, and S. Durucan, 2005.CO2 storage in deep unminable coal seams.Oil & gas science and technology, 60 (3), 547-558. 23- Cline, J.T., 1998. Treatment and Discharge of Produced Water for Deep Offshore Disposal.presented at the API Produced Water Management Technical Forum and Exhibition, Lafayette, LA, Nov. 17-18. 18 ACS Paragon Plus Environment

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Energy & Fuels

24-Hamawand, I., Yusaf, T. and Hamawand, S.G., 2013. Coal seam gas and associated water: a review paper. Renewable and Sustainable Energy Reviews, 22, pp.550-560. 25-Rice, C.A. and Nuccio, V., 2000. Water produced with coal-bed methane. US Geological Survey Fact Sheet FS–156–00, p.2.

26- R. Sakurovs and S. Lavrencic, 2011.Contact angles in CO2-water-coal systems at elevated pressures. International Journal of Coal Geology, 87(1), 26-32. 27-N.S. Kaveh, K.H. Wolf, S.N. Ashrafizadeh and E.S.J. Rudolph, 2012. Effect of coal petrology and pressure on wetting properties of wet coal for CO2 and flue gas storage. International Journal of Greenhouse Gas Control, 11, 91-101. 28-Dickson, J.L., Gupta, G., Horozov, T.S., Binks, B.P. and Johnston, K.P., 2006. Wetting phenomena at the CO2/water/glass interface.Langmuir, 22(5), pp.2161-2170. 29-D.N. Espinoza and J.C. Santamarina, 2010.Water-CO2-mineral systems: Interfacial tension, contact angle, and diffusion-Implications to CO2 geological storage. Water Resources Research, 46(7), 1-10. 30-S. Saraji, L. Goual, M. Piri and H. Plancher, 2013.Wettability of supercritical carbon dioxide/water/quartz systems: simultaneous measurement of contact angle and interfacial tension at reservoir conditions. Langmuir, 29(23), 6856-6866. 31-M. Sarmadivaleh, A. Al-Yaseri, and S. Iglauer, 2015. Influence of temperature and pressure on quartz-water-CO2 contact angle and CO2-water interfacial tension.Journal of colloid and interface science, 441, 59-64. 32-A. Al-Yaseri, M. Lebedev, A. Barifcaniand S. Iglauer, 2016.Receding and advancing (CO2+ brine+ quartz) contact angles as a function of pressure, temperature, surface roughness, salt type and salinity. The Journal of Chemical Thermodynamics, 93, 416-423. 33-M. Arif, A. Al-Yaseri, A. Barifcani, M. Lebedev and S. Iglauer, 2016. Impact of pressure and temperature on CO2-brine-mica contact angles and CO2-brine interfacial tension: Implications for carbon geo-sequestration. Journal of colloid and interface science, 462, 208215. 34-H. Roshan, A. Al-Yaseri, M. Sarmadivaleh, S. Iglauer, 2016.On Wettability of Shale Rocks.Journal of colloid and interface science, 475, 104-111. 19 ACS Paragon Plus Environment

Energy & Fuels

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

35-Hu, H., Li, X., Fang, Z., Wei, N. and Li, Q., 2010. Small-molecule gas sorption and diffusion in coal: Molecular simulation. Energy, 35(7), pp.2939-2944. 36-Tiab, E.C. Donaldson, 2004. Petrophysics-Theory and Practice of Measuring Reservoir Rock and Fluid Transport Properties. Gulf Publishing Co., Elsevier, USA, pp. 889 37-S. Saraji, M. Piri, and L. Goual, 2014.The effects of SO2 contamination, brine salinity, pressure, and temperature on dynamic contact angles and interfacial tension of supercritical CO2/brine/quartz systems. International Journal of Greenhouse Gas Control, 28, 147-155. 38- Thakur, P., 2017. Advanced Reservoir and Production Engineering for Coal Bed Methane, Elsevier. 39- Milewska-Duda, J., Duda, J., Nodzeñski, A. and Lakatos, J., 2000. Absorption and adsorption of methane and carbon dioxide in hard coal and active carbon.Langmuir, 16(12), pp.5458-5466.

40- Bachu, S., Gunter, W.D. and Perkins, E.H., 1994. Aquifer disposal of CO 2: hydrodynamic and mineral trapping. Energy Conversion and Management, 35(4), pp.269279. 41- Dietrich, S. and Napiórkowski, M., 1991. Microscopic derivation of the effective interface Hamiltonian for liquid-vapor interfaces. Physica A: Statistical Mechanics and its Applications, 177(1-3), pp.437-442. 42-Merath C., 2008.Microscopic calculation of line tensions.PhD thesis, Institute for Theoretical and Applied Physics University of Stuttgart, pp.160. 43-GB/T 212-2008, 2008. Chinese national standard.Coal, Proximate analysis of coal (inChinese). 44-GB/T 5751-2009, 2009. Chinse national standard.Coal, Classification of Chinesecoals (inChinese). 45-Wenzel, R. N., 1936. Resistance of solid surfaces to wetting by water. Industrial & Engineering chemistry, 28, pp.988-994.

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Page 20 of 22

Page 21 of 22

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

46-Wang, S., Edwards, I.M. and Clarens, A.F., 2012. Wettability phenomena at the CO2– brine–mineral interface: implications for geologic carbon sequestration. Environmental science & technology, 47(1), pp.234-241. 47- A. Z., Al-Yaseri, H Roshan, M Lebedev, A Barifcani, S Iglauer, 2016. Dependence of quartz wettability on fluid density. Geophysical Research Letters, 43, 3771-3776. 48-J.C. Love, L.A. Estroff, J.K. Kriebel, R.G. Nuzzo, and G.M. Whitesides, 2005.Selfassembled monolayers of thiolates on metals as a form of nanotechnology. Chemical reviews, 105, 1103-1169. 49-J. Mahadevan, 2012. Comments on the paper titled. contact angle measurements of CO2– water–quartz/calcite systems in the perspective of carbon sequestration: a case of contamination. International Journal of Greenhouse Control 7, 261–262. 50- S. Iglauer, A. Hassan, M. Sarmadivaleh, K. Liu, C. Pham, 2014. Contamination of silica surfaces: impact on water-CO2-quartz and glass contact angle measurements. International Journal of Greenhouse Gas Control, 22, 325–328. 51-El-Maghraby, R.M., Pentland, C.H., Iglauer, S. and Blunt, M.J., 2012. A fast method to equilibrate carbon dioxide with brine at high pressure and elevated temperature including solubility measurements.The Journal of Supercritical Fluids, 62, pp.55-59. 52- S. Mori, T. Hara, K. Aso and H. Okamoto, 1984.Zeta potential of coal fine-particles in aqueous suspension.Powder technology, 40(1-3), 161-165. 53- R. Maršálek, 2008.The influence of surfactants on the zeta potential of coals. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 31(1), 66-75. 54- K. Soga and J.K. Mitchell, 2005.Fundamentals of soil Behavior.Wiley, Third Edition, ISBN, 10, 0-471. 55- H. Roshan and M.A. Aghighi, 2012. Analysis of pore pressure distribution in shale formations under hydraulic, chemical, thermal and electrical interactions. Transport in porous media, 92(1), 61-81. 56- M. Binazadeh, M. Xu, A. Zolfaghari and H. Dehghanpour, 2016. Effect of Electrostatic Interactions on Water Uptake of Gas Shales: The Interplay of Solution Ionic Strength and Electrostatic Double Layer. Energy and Fuels, 30, 992-1001. 57- R. Garcia, K. Osborne and E. Subashi, 2008.Validity of the “sharp-kink approximation” for water and other fluids. The Journal of Physical Chemistry B, 112(27), 8114-8119.

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Energy & Fuels

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

58- S.M. Gatica, J.K. Johnson, X.C. Zhao and M.W. Cole, 2004.Wetting transition of water on graphite and other surfaces. The Journal of Physical Chemistry B, 108(31), 11704-11708. 59- Cheng, E., Cole, M.W., Saam, W.F. and Treiner, J., 1991. Helium prewetting and nonwetting on weak-binding substrates. Physical review letters, 67(8), p.1007. 60- R. Farokhpoor, B.J.A. Bjørkvik, E. Lindeberg, O. Torsæter, 2013. Wettability behaviour of CO2 at storage conditions International Journal of Greenhouse Gas Control, 12, 18–25. 61- D. Yang, Y. Gu and P. Tontiwachwuthikul, 2008. Wettability Determination of the Crude Oil-Reservoir Brine-Reservoir Rock System with Dissolution of CO2 at High Pressures and Elevated Temperatures. Energy & Fuels, 22(4) (2008), 2362-2371. 62- M. Arif, A. Barifcani, M. Lebedev, and S. Iglauer, 2016b. CO2-wettability of low to high rank coal seams: Implications for carbon sequestration and enhanced methane recovery. Fuel, 181, pp.680-689. 63- E. Chibowski and K. Terpilowski, 2008. Surface free energy of sulfur-Revisited: I. Yellow and orange samples solidified against glass surface. Journal of Colloid and Interface Science, 319(2), 505-513. 64- R. Tadmor, 2004. Line Energy and the Relation between Advancing, Receding, and Young Contact Angles. Langmuir, 20(18), 7659-7664. 65- Georgiadis, A., Maitland, G., Trusler, J.M. and Bismarck, A., 2010. Interfacial tension measurements of the (H2O+ CO2) system at elevated pressures and temperatures.Journal of Chemical & Engineering Data, 55(10), pp.4168-4175. 66- A. Z., Al-Yaseri, H., Roshan, Y., Zhang, T., Rahman, A., Barifcani, S., Iglauer, 2017. Effect of temperature on CO2/brine/dolomite wettability: hydrophilic versus hydrophobic surfaces, Energy & Fuels, 31, 6329-6333. 67- F. Mugele, I. Siretanu, N. Kumar, B. Bera, L. Wang, R. de Ruiter, A. Maestro, M. Duits, D. van den Ende and I. Collins, 2016. Insights from Ion Adsorption and Contact-Angle Alteration at Mineral Surfaces for Low-Salinity Waterflooding.Society of Petroleum EngineersJournal, 1-10.

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