multiscale imaging of gas adsorption in shales

Multiscale Imaging of Gas Adsorption in Shales

Hamza Aljamaan, Cynthia M. Ross, Anthony R. Kovscek

SCCS Annual Affiliate Meeting 2017

May 25st 2017

1

1. The problem…

What I’m going to talk about….

2. Methodology

4. Conclusions3. Results

2

5×2.5 cmParticle

Powder

Intact Core

3

Hale, B. W., & Hall, R. K. (2017, February). Historical Terminal Decline Rates Review of Unconventional Reservoirs

in the United States. In SPE Unconventional Resources Conference. Society of Petroleum Engineers.

Production Profile

Recovery Factor ~ 10-20%

4

Walker, G., Branter, T., & Miller, P. (2017, February). Adsorbed Gas Composition, and its Impact on Early Time

Production. In SPE Unconventional Resources Conference. Society of Petroleum Engineers.

Total Gas (𝝃) = Adsorbed Gas + Free Gas (ф)

Gas Storage Capacity and Distribution

• Volumetric experimental data reveal the potential of CO2 storage in shale

Barnett 26-Ha

Pore Pressure = 804 psia Barnett #26 Haynesville GU 1-2

Free Gas (scf/ton) 40.9 70.6

CH4 Adsorbed Gas (scf/ton) 24.5 38.2

CO2 Adsorbed Gas (scf/ton) 235.8 631.8

5

Aljamaan, H., Al Ismail, M., & Kovscek, A. R. (2016). Experimental investigation and Grand Canonical Monte

Carlo simulation of gas shale adsorption from the macro to the nano scale. Journal of Natural Gas Science and

Engineering.

CO2 Adsorbed vs. Free gas

6

Barnett 26-Ha Eagle Ford EF-4 Haynesville TWG3-2 Permian P-2

Source Sample Depth (ft) Ro TOC Clays Carbonates Quartz Feldspar Pyrite

Barnett 26-Ha 8620.1 - 11.7* 25.2 10.4 45.1 5.8 1.7

Eagle Ford EF-4 11184.8 1.39 5.1 20.3 48.9 18 3.8 3.9

Haynesville TWG3-2 11134.05 1.37 1.9 22.8 49.5 16.8 6.9 2.0

Permian+ P-2 10134.25 1.28 0.5 5.5 68.8 17.5 7.3 1.0

Study Samples

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Gas Adsorption Imaging

GE HiSpeed CT/I fifth generation medical scanner operated in helical mode

Voxel size: 0.19 ˣ 0.19 ˣ 1 mm

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𝜉 =𝐶𝑇 𝑔 𝑟 − 𝐶𝑇 𝑎 𝑟

𝐶𝑇𝑔𝑎𝑠 − 𝐶𝑇𝑣𝑎𝑐𝑢𝑢𝑚

Storage Capacity (𝝃) = Adsorbed Gas + Free Gas (ф)

Gas Adsorption Imaging

9

Kr

CO2

Barnett Eagle Ford Haynesville Permian

5.6

10.2

9.9

12.8 17.5

11.0

14.4

7.8

Kr vs CO2 Storage Capacity

Boyle’s Law, whole core CT imaging, whole core

Source Sample Depth He Kr* CO2*

Barnett 26-Ha 8620.1 5.5+ 9.9 12.8

Eagle Ford EF-4 11184.8 6.3 11.0 17.5

Haynesville TWG3-2 11134.05 4.5 7.8 14.4

Permian P-2 10134.25 - 5.6 10.2

+ Aljamaan, 2013, * CT storage capacity for each gas at comparable equilibrium pressures of 179 to 250 psi for Kr and ~ 800 psi for CO2

Effective porosity (He) and storage capacity by gas type (Kr and

CO2) at comparable pressures

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Porosity and Storage Capacity

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𝜉avg= 6.38%

Pp=428.9 psi t= 24.16 hrs

𝜉𝜉avg= 6.60%

Pp=435 psi t= 1.11 hrs

Permian P-2

Eagle Ford EF-4

𝜉avg= 10.95%

Pp=240 psi t= 28 hrs𝜉avg= 6.68%

Pp=327.4 psi t= 3.15 hrs𝜉

(a) (b)

(c) (d)

Kr Adsorption vs Time

12

𝜉avg= 7.10%

Pp=761 psi t= 120.34 hrs𝜉𝜉avg= 6.78%

Pp=637 psi t= 64.14 hrs

𝜉avg= 6.38%

Pp=428 psi t= 46.98 hrs

𝜉avg= 5.62%

Pp=179 psi t= 22.81 hrs

(a)

(b)

(c)

(d)

(a) (b) (c) (d)

Kr Adsorption vs Pore Pressure

13

Pupstream=815.2, Pdownstream=779 psit ≈ 24 hours

Pupstream=762, Pdownstream=755 psit ≈ 48 hours

Pupstream=804, Pdownstream=690 psit ≈ 2.5 hour

Constant Upstream Injection

CO2 Adsorption vs Time

• FEI Magellan 400 XHR SEM

• 15kv, 13 nA, CBS-A, 200X, dwell 1 sec

• Bruker Quantax XFlash 6160 EDS

• Spectra maps and phase analysis

• Spot size 0.75 m

• MAPS 2.0.41.964

• Mosaic acquisition and construction

14

MAPS 2.0.41.964

Scanning Electron Microscope (SEM)

and Energy Dispersive Spectroscopy

(EDS)

• Image collection

• Elemental data collection

• Qmap

• Phase analysis

15

Fe Ca Carbonates and

carbonate-rich

matrix

Silicates and

silicate-rich

matrix

Pyrite

Organic matter

EFSEM and EDS Analysis

1 inch diameter

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Pixel Size: 1.45 µm

Eagle Ford

CO2KrSEM

Voxel dimensions: 190×190×1000 μm

20 40 60 80 100

10

20

30

40

50

60

70

80

90

100

0

0.05

0.1

0.15

0.2

0.25

𝝃

Multiscale Image Registration

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Barnett 26-Ha Eagle Ford EF-4 Haynesville TWG3-2

Permian P-2, CT Permian P-2, µCT core top Permian P-2, µCT SEM mount

CT - 190×190×1000 μm

µCT - 27 x 27 x 27 µmDense CT and µCT Regions

Kr CO2

• CO2 and Kr storage distribution slices aligned with SEM mosaic

20 40 60 80 100

10

20

30

40

50

60

70

80

90

100

0

0.05

0.1

0.15

0.2

0.25

Low 𝝃

High 𝝃𝝃

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Eagle FordCT/SEM Registration

CO2

20 40 60 80 100

10

20

30

40

50

60

70

80

90

100

0

0.05

0.1

0.15

0.2

0.25

300 µm 30 µm

P

OM

P – Pyrite

OM – Organic Matter

Matrix – mixture of clay

and carbonate1 inch diameter

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Pixel Size: 1.45 µm

Pixel Size: 366 nm Pixel Size: 74 nm

𝝃Interpretation – Eagle Ford, High 𝝃

20

Eagle Ford

Carbonates and

carbonate-rich matrix

Silicates and silicate-

rich matrix

Silicate- and


(~50/50)

Pyrite

Organic matter

High

Open fractures

and less

secondary

mineralization

Low

Extensive

secondary

mineralization

Interpretation – High and low storage capacity regions

Kr CO2

• Inaccessible zones appear with both CO2 and Kr but is more evident in CO2

• Large isolated nodules correspond to low storage capacity zones

• Kr and CO2 mostly flows through the fractures

20 40 60 80 100

10

20

30

40

50

60

70

80

90

100

0

0.05

0.1

0.15

0.2

0.25

20 40 60 80 100

10

20

30

40

50

60

70

80

90

1000

0.05

0.1

21

𝝃𝝃

Interpretation - Haynesville TWG3-2

Core CT data

200 µm

CO2

20 40 60 80 100

10

20

30

40

50

60

70

80

90

100

0

0.05

0.1

0.15

0.2

0.25

21 1 - Pyrite 2 - Barite

• Nodules (pyrite, barite, carbonate) low Kr and CO2 adsorption

200 µm

22

Pixel Size: 366 nm Pixel Size: 366 nm

𝝃

Interpretation - Haynesville TWG3-2

23

Haynesville

Carbonates and



rich matrix

Barite

Pyrite

Organic matter

High

Open fractures

and less

secondary

mineralization

Low

Extensive

secondary

mineralization


24

Permian

Carbonates and



rich matrix

Barite

Pyrite

Organic matter

High

Less secondary

mineralization

Low

Extensive

secondary

mineralization


Kr CO2

25

𝝃

Interpretation – Barnett 26-Ha

Barnett

Carbonates and



rich matrix

Pyrite

Organic matter

High

Open fractures

and secondary

carbonate

mineralization

in clay matrix

Low

Clay-rich

regions,

secondary

carbonates as

fracture fill

26


27

Sample

Maximum

Volume

@ STP

(cc/g)

Pore

Capacity

(cc/g)

Surface

Area

(m2/g)

Gas

Barite 5.4 0.009 0.980 N2

Pyrite 3.7 0.006 1.513 N2

CaCO3 3.5 0.005 1.239 N2

Illite* 63.6 0.079 15.500 Ar

Silurian Kerogen* 227.9 0.277 50.116 Ar

Eagle Ford EF-4 30.2 0.047 13.744 N2

Haynesville TWG3-2 21.6 0.034 5.901 N2

* Courtesy of R. Holmes

Low Pressure Adsorption

• Work flow of multiscale (cm to nm) imaging

Gas accessibility and storage capacity in intact shale cores

SEM mosaics of either core face or interior slices

Elemental mapping and interpretation

Image registration methods (same resolution and multiscale)

• Storage capacity of CO2 (10 to 17.5%) in all study cores is greater than Kr (5.6 to 11%). Both

are greater than the He porosity or amount of void space (4.5 to 6.3 %)

• Open fractures, secondary mineralization, matrix composition, and other features are interpreted

with respect to their impact on accessibility and gas storativity

• Gas storage and its distribution is controlled by

porosity

accessibility

sorption capacity of minerals and organic matter

28

Conclusions

• Stanford Center for Carbon Storage (SCCS)

• SUPRI-A Industrial Affiliates

• BP and BHP Billiton

• H. Aljamaan acknowledges his graduate fellowship from Saudi Aramco

• Randall Holmes

• Stanford Nano Shared Facilities (SNSF)*

*Part of this work was performed at SNSF using a ZEISS Xradia 520 Versa, acquired with support from NSF under

award CMMI-1532224. SNSF is supported by the NSF as part of the National Nanotechnology Coordinated

Infrastructure under award ECCS-154215.

Slide 29Acknowledgements / Thank You / Questions

multiscale imaging of gas adsorption in shales

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