INJEÇÃO DE CO2 PARA PRODUÇÃO ACRESCIDA DE METANO DE CARVÃO

EM CAMADA

CO2 INJECTION FOR ENHANCED COALBED METHANE (ECBM)

C.F. Rodrigues1 & M.J. Lemos de Sousa3

1 FP-ENAS, University of Fernando Pessoa, Praça de 9 de Abril, 349, 4249-004

Porto. Portugal. E-mail: cfrodrig@gmail.com

3 FP-ENAS, University of Fernando Pessoa, Praça de 9 de Abril, 349, 4249-004

Porto. Portugal and Academia das Ciências de Lisboa, Rua da Academia das

Ciências, 19, 1249-122 Lisboa. Portugal. E-mail: lemosdesousa@gmail.com

Workshop: Tecnologias CCUS

Universidade de São Paulo, 16 Novembro 2017

WHY

CO2-ECBM?

►SECURE

►COMPETITIVE

►SUSTAINABLE ENERGY

CLIMATE STRATEGY

REAL ENERGY DEMAND

NON-RENEWABLE ENERGIES

Zero Emissions

Technologies

CCS Technologies

Clean Coal Technologies

ED 2009/31/ECGeological Storage of CO2

Coal to Liquids

ED 2003/87/EC

ED 2004/101/EC

CCS TECHNOLOGIES

CAPTURE STORAGETRANSPORT

(Lemos de Sousa and Rodrigues, 2011)

Deep saline

aquifers

Depleted

Oil and Gas

reservoirs

Coal

seams

RESERVOIR CHARACTERIZATION

Shale

Gas

No

►STORAGE

►CIRCULATION

ALL THE RESERVOIRS HAVE THE SAME PERFORMANCE IN…

1- Static component

2- Dynamic component

Geological Model

Fluid flow Model

RESERVOIRS PERFORMANCE DEPENDS DIRECTLY ON TWO COMPONENTS

CONCEPTS NEED TO BE

UNDERSTOOD?

Free state

Absorbed state

Scale

4 µ

Grains

Fluids

Fluids are HOMOGENEOUSLY DISPERSED on the porous

structure, depending on their concentrations

Laminar Flow

u = flow rate (cm/s)

K = permeability (mD or D)

µ = fluid viscosity

P = pressure (atm)

Z = distance (cm)

dz

dp

m=

ku -

Fluid circulates into a specific direction depending on the

PRESSURE GRADIENT and on FLUID VISCOSITY.

Darcy Law

Free state

Absorbed state

Adsorbed state

Fluids are HETEROGENEOUSLY DISPERSED

on the porous structure.

Fluid molecules grabbed

to the pore walls.

Due to the high affinity to

the organic structure.

Organic Fragment

Pores

Fluid

Scale

6 µ

Laminar Flow

Fluid flow depends on the PRESSURE GRADIENT OF THE

DIFFERENT COMPONENTS PRESENT ON THE FLUID

MIXTURE and THEIR INTERACTIONS WITH the ORGANIC

STRUCTURE, as well as, on the ORGANIC MATTER

SHRINKING AND SWELLING EFFECTS.

Darcy Law

Diffusional Flow

CONVENTIONAL RESERVOIRSVS

UNCONVENTIONAL RESERVOIRS

Scale: 4 µ

Grains

FluidLarger pores implies

higher storage capacity.

Pores < dimensions Pores > dimensions

Scale: 6 µ

Pores < dimensions Pores > dimensions

Pores

FluidSmaller pores implies

higher storage capacity.

Organic Fragments

STORAGE CAPACITY

Conventional

Reservoirs

Larger pores implies higher

storage capacity

Unconventional

Reservoirs(organic-rich rock)

Smaller pores implies

higher storage capacity

Smaller pores implies higher internal

surface areas, and consequently higher

storage capacities.

CO2-ECBM

HOW IT WORKS ?

Dewatering

stage

Stableproduction

stageDecline

stage

Production

TIME

CBM PRODUCTION HISTORY

(Rice et al. 1993)

(Rodrigues, 2002)

Dewatering and reservoir

pressure depletion is a simple

but relatively inefficient

process, recovering less than

50% of the gas in place.

CBM wells initially primarily produce water;

then gas production eventually increases,

while water production declines.

Dewatering (drilling of a well) induces the

hydrostatic pressure reduction and

consequently accelerates the desorption

process.

FACTORS INFLUENCING CO2 STORAGE AND ENHANCED GAS RECOVERY IN COAL SEAMS

ECBM and storage of CO2 in coal seams processes involve:

1. CAPTURING CO2 from a flue gas stream

2. COMPRESSING CO2 for transport to an injection site

3. INJECTION of CO2 into the coal to enhance methane recovery

and/or store CO2.

► Fracture permeability

► Development history

► Gas migration

► Coal maturation

► Coal distribution

► Geologic structure

► Well completion options

► Hydrostatic pressure

► Produced water management

CBM and ECBM PRODUCTION POTENTIAL DEPENDS ON :

VARY FROM

BASIN TO BASIN

CO2 INJECTION ECBM RECOVERY:HOW IT WORKS ?

► To reduce the hydrostatic pressure, usually by dewatering the

formation and/or to reduce the partial pressure of the methane

by injecting CO2 and then the methane on the surface gets displaced by the

CO2

► Hydraulic fracturing are, normally, used to assist recovery

► Many wells at relatively close spacing must be drilled to

achieve economic gas production

Fracture (CLEAT)

system one of the

main controlling

factor

LOW PERMEABILITY IS A FACT, SO…

►CO2 is stored in coal following two process: sorption and

diffusion.

► In coal seams, ADSORPTION TRAPPING is the MAIN

SEQUESTRATION METHOD.

►The adsorption process causes the CO2 to bond to the

coal structure, which will allow to CO2 TO BE

PHYSICALLY AND “PERMANENTLY” TRAPPED on the

coal, provided sufficient pressure is maintained.

COAL IS A SAFETY AND A PERMANENT”OPTION FOR CO2 STORAGE ?

CO2 can safely remain stored

in coal for GEOLOGICALLY

SIGNIFICANT TIME PERIODS

PREDICTION OF CO2SEQUESTRATION CAPACITY

ORIGINAL GAS IN PLACE

(OGIP) VOLUMETRIC

COMPUTATION

EQUATION TO ESTIMATE

CO2 STORAGE CAPACITY IN

COAL SEAM(S)

Defined by Simplifying

This equation is applicable for 100% gas saturation in coal matrix and

adsorption process as the main and the only storage mechanism in coal seams.

CO2 STORAGE CAPACITY = CO2 density, kg/m3 x Prospective area, m2

x Coal seam(s) thickness, m x Coal bulk density, kg/m3 x Gas sorption

capacity, m3/kg

COAL PROPERTIES AT A RESERVOIR

SCALE ?

IT IS MAINLY CONTROLLED BY PHYSICAL MECHANISMS

COAL IS A

MICROPOROUS

RESERVOIR

Micropores

Mesopores

Macropores

It means

Gas in coal is mainly stored in the adsorbed

state on the INTERNAL SURFACE AREA of the

coal microporous structure.

To store a volume of gas much higher

than its pore volume capacity.

GAS STORAGE IN A COAL SEAM

It means

Was used to establish the adsorbed

volume kinetic equilibrium

LLg PPPVV =

Vg - Gas volume (m3/ton)

P - Equilibrium pressure (MPa)

VL - Langmuir Volume (m3/ton)

PL - Langmuir Pressure (MPa)

METHODOLOGY

SORPTION ISOTHERMS

2

13851.3

=

ii

s

VV

brD

D - Diffusion coefficient (cm2/sec)

b - Slope (first linear part of the data curve)

rs - Spherical particle radius (cm)

Vi - Gas content at the end of step I (cm3/ton)

Vi-1 - Gas content at the end of step I-1 (cm3/ton)

Requires precise and continuous monitoring ofchanges in pressure and gas concentration in bothcells, during the whole sorption

DETAILED STUDY OF THE CLEAT SYSTEM

►PRESSURE

►TEMPERATURE

►GAS COMPOSITION

►MOISTURE

►PETROGRAPHIC CHARACTERISTICS

►Mean Random Vitrinite Reflectance

►Vitrinite content

►Liptinite content

► Inertinite content

►Mineral Matter content

PARAMETERS CAPABLE TO INFLUENCE SORPTION BEHAVIOR

PRESSURE EFFECT

0

1

2

3

4

5

6

7

0 1 2 3 4 5 6

Pressure (MPa)

Gas

Volume (cm

3/g

)

P2

P1

G2

G1

40

80

120

160

200

240

200 400 600 800psi

P1

G1

TEMPERATURE EFFECT

0

2

4

6

8

10

12

14

0 2 4 6 8

Pressure (MPa)

Gas

Volum

e (cm

3/g

)

80

160

240

320

400

480

250 500 750 1000psi

T = 30ºC

T = 22ºC 15%

T = 30ºC

MOISTURE EFFECT

0

1

2

3

4

5

6

7

0 1 2 3 4 5 6

Pressure (MPa)

Gas

Volum

e (cm

3/g

)

Moisture 3.0%

■ Moisture 5.7%

▲ Moisture 11.5% 40

80

120

160

200

240

200 400 600 800psi

(MHC = 4.3%)

MINERAL MATTER EFFECT

0

1

2

3

4

5

0 2 4 6 8Pressure (MPa)

Gas

Volum

e (c

m3/g

)

MM = 44%

MM = 7%61%

34

68

102

136

170

250 500 750 1000psi

RANK EFFECT

0

1

2

3

4

5

6

7

0 2 4 6 8

Pressure (MPa)

Gas

Volum

e (c

m3/g

) Rr = 1.93%

Rr = 0.91%

Rr = 0.43%

63%

28%

40

80

120

160

200

240

250 500 750 1000psi

scf/

ton

PETROGRAPHIC COMPOSITION EFFECT

0

1

2

3

4

5

6

7

0 1 2 3 4 5 6

Pressure (MPa)

Gas

Volum

e (c

m3/g

)

V=72%; L=6%; I=22%

V=83%; L=6%; I=11%

40

80

120

160

200

240

200 400 600 800psi

GAS COMPOSITION EFFECT

0

2

4

6

8

10

12

14

16

0 1 2 3 4 5 6

Pressure (MPa)

Gas

Volum

e (c

m3/g

) CO2

N2

CH4 + CO2 + N2

CH4

100

200

300

400

500

200 400 600 800psi

COMPRESSIBILITY FACTOR

ACCURACY VALUES FOR THE COMPRESSIBILITY FACTOR

10

20

30

40

50

60

0 200 400 600 800

P ressure (psi)

0.0001

0.001

0.01

0.1

N2

Accuracy

50

100

150

200

250

300

0 200 400 600 800 1000

P ressure (psi)

0.0001

0.001

0.01

0.1

CH4 + CO2 + N2

Accuracy

40

60

80

100

120

140

160

180

200

220

0 200 400 600 800 1000

Pressure (psi)

0.0001

0.001

0.01

0.1

Accuracy

CH4

150

200

250

300

350

400

450

0 200 400 600 800

P ressure (psi)

0.0001

0.001

0.01

0.1

Accuracy

CO2

GAS SORPTION ISOTHERMS FROM LIGNITE TO ANTHRACITE

0

50

100

150

200

250

300

350

400

450

0 100 200 300 400 500 600 700 800 900

Pressure (psi)

Gas c

on

ten

t (s

cf/

ton

)

G

F

HE

D

C

B A (Rr=0.17%)(Rr=0.31%)

(Rr=0.55%)

(Rr=0.62%)

(Rr=0.72%)

(Rr=5.31%)

(Rr=2.10%)

(Rr=3.07%)

(a) cleat characteristics in plan view;

(b) cleat hierarchies in cross- section view

(Laubach et al 1998)

DETAILED STUDY OF THE CLEAT SYSTEM

► CLEAT DIRECTIONS RELATIVE TO A REFERENCE

► CLEAT FREQUENCY

► CLEAT HEIGHT

► CLEAT LENGTH

► CLEAT SPACING

► CLEAT APERTURE

► NUMBER OF CLEATS FILLED BY MINERALS

► NUMBER OF CLEAT INTERSECTIONS

(CONNECTIVITY INDEX)

COAL CLEAT CHARACTERISTICS

Plane W-E (W dip direction)

0

20

40

60

80

100

dip (degree)

Fre

qu

en

cy (

%)

10 20 30 40 50 60 70 80

Cleat frequency

(decrease order)

Cleat lines measured in N-S

plane (N dip direction)

Cleat lines measured in W-E

plane (E dip direction)

1 88º ® 0º 88º ® 90º

2 89º ® 0º 87º ® 90º

3 87º ® 0º 85º ® 90º

4 85º ® 0º 86º ®90º

5 86º ® 0º 84º ® 90º

6 80º ® 0º 89º ® 90º

7 3º ® 0º; 83º ® 0º and 84º ® 0º 83º ® 90º

8 2º ® 0º 3º ® 90º

9 5º ® 0º 82º ® 90º

10 82º ® 0º 7º ® 90º and 5º ® 90º

Mean Direction = 89-045

Mean Resultant dir'n = 89/045

Mean Resultant length = 1,00

(Variance = 0,00)

Calculated. girdle: 89/045

N

Plane: N 135º, 89ºE

Mean Orientation = 87/037

Mean Resultant dir'n = 87-037

Mean Resultant length = 1,00

(Variance = 0,00)

Calculated. girdle: 8/145

Calculated beta axis: 82-325

N

Mean Plane: N 127º, 87ºE

Dip direction interval 120º - 150º

Cleat frequency 1

STATISTICAL ANALYSES FROM GEOREFERENTIATED DATA

Class

designationDip interval

Class 0 0º

Class 1 > 0º and £ 30º

Class 2 > 30º and £ 60º

Class 3 > 60º and £ 90º

Class 4 90

Connectivity frequency

0%

10%

20%

30%

40%

50%

0-1 0-2 0-3 0-4 1-2 1-3 1-4 2-3 2-4 3-4

Classes

Fre

qu

en

cy

(%

)

CONNECTIVITY FREQUENCY

(Example)

Thank you