Langmuir,
Journal Year:
2024,
Volume and Issue:
40(8), P. 4496 - 4513
Published: Feb. 13, 2024
An
acid
solution
improves
the
pore-plugging
problem
in
hydraulic
fracturing,
which
turn
permeability
of
coal
seam.
The
study
aimed
to
investigate
effect
mixed
on
micronano
mechanical
properties
and
surface
morphology
acidified
was
analyzed
from
scale
using
atomic
force
microscopy
(AFM)
scanning
electron
microscopy.
Additionally,
characteristics
were
examined
mode
an
microscope.
Furthermore,
complexity
connectivity
pores
samples
investigated
low-temperature
nitrogen
adsorption
mercury
intrusion
porosimetry
methods
fractal
theory.
results
indicated
that
minerals
dissolved,
loosening
increasing
pore
structure.
Mineral
deformation
weakened
at
scale,
mean
elastic
modulus
(B#
E#)
decreased
by
28.78
25.66%
compared
raw
coal.
effectively
enlarged
diameter,
transitioning
micropores
mesopores
macropores,
total
volume
increased
1.88
times
1.25
times,
Kn
0.064
0.581
0.37,
respectively.
type
methane
diffusion
changed
Knudsen
transition-type
diffusion.
tortuosity
structure
decreased,
dimension
nearly
three
times.
research
indicate
decrease
after
acidification
microstructural
changes
can
promote
migration
(diffusion-seepage),
provide
theoretical
guidance
for
coalbed
extraction
low-permeability
reservoirs.
Energy & Fuels,
Journal Year:
2024,
Volume and Issue:
38(5), P. 3517 - 3538
Published: Feb. 14, 2024
Enhanced
coal
seam
methane
extraction
by
injecting
gas
is
an
emerging
technology
to
both
reduce
greenhouse
emissions
and
improve
recovery.
In
this
paper,
the
experimental
field
research
progress
on
injection
for
driving
displacing
are
reviewed
from
perspectives
of
micro,
meso,
macro
scales.
The
microscopic
scale
perspective
involves
intuitively
analyzing
interaction
process
relationship
between
strong
adsorption
gases
(CO2,
LCO2,
SCCO2)
relatively
weak
(CH4,
N2)
injected
into
samples,
changes
in
number
micropores,
mesopores,
macropores
samples
using
NMR
low-temperature
nitrogen
equipment,
visualizing
multiphase
flow
pore
structures
microfluidic
methods.
For
mesoscopic
scale,
multiple
equipment
means
(SEM,
NMR,
liquid
adsorption,
etc.)
were
used
quantitatively
analyze
effects
different
fracture
widths,
degrees
metamorphism,
composition
seepage
adsorption–desorption
rate.
macroscopic
physical
mechanical
properties
rock
analyzed
pseudotriaxial
or
true
triaxial
during
parameters
axial
pressure
confining
pressure,
especially
related
experiments
single
component
multicomponent
gases.
Moreover,
future
perspectives,
some
key,
emerging,
intelligent
technologies
enhanced
will
be
put
forward.
ACS Omega,
Journal Year:
2024,
Volume and Issue:
unknown
Published: July 20, 2024
Important
breakthroughs
have
recently
been
achieved
in
deep
coalbed
methane
(CBM)
exploration
and
development
regions
such
as
the
eastern
margin
of
Ordos
Basin,
China.
Investigating
characteristics
various-scale
pores
coalbeds
is
great
significance
for
resource
assessment
selection
favorable
zones
CBM
exploration.
Herein,
six
coal
samples
were
selected
from
Shanxi
Taiyuan
Formations
Daning-Jixian
block
on
Basin.
Low-pressure
CO
Physics of Fluids,
Journal Year:
2024,
Volume and Issue:
36(7)
Published: July 1, 2024
Enhanced
coalbed
methane
recovery
with
CO2
coal
seam
storage
(CO2-ECBM)
technology
is
an
important
way
to
achieve
China's
strategic
goals
of
carbon
peak
and
neutrality.
Presently,
date
there
has
been
rarely
research
conducted
on
the
effect
sample
scale
pore
structure
under
supercritical
(ScCO2)
fluids.
In
this
study,
a
high-pressure
geological
environment
simulation
system
was
adopted
analyze
samples
different
scales
for
ScCO2
saturation.
Subsequently,
low-pressure
nitrogen
gas
adsorption
(LP-N2GA),
mercury
intrusion
porosimetry
(MIP),
low-field
nuclear
magnetic
resonance
(LF-NMR)
were
used
fractal
dimension
changes
in
saturated
at
scales.
The
experimental
results
show
that
mesopore
ratios
cylindrical
granular
decrease
by
average
1.68%
2.30%,
respectively,
after
saturation
ScCO2.
proportion
macropores
increased
5.50%
saturation,
while
changed
176.86%
compared
coal.
obtained
LP-N2GA,
MIP,
LF-NMR
all
decreasing
trend,
again
confirming
modification
surface
Finally,
conceptual
model
presented
mechanism
difference
transport
paths
molecules
main
reason
evolution
structure.
addition,
impact
amount
laboratory
using
assessment
capacity
discussed.
Therefore,
study
are
expected
provide
reference
CO2-ECBM
project.
Energy & Fuels,
Journal Year:
2024,
Volume and Issue:
38(5), P. 4010 - 4020
Published: Feb. 14, 2024
Coal-bed
methane
(CBM),
shale
gas,
and
tight
sandstone
gas
are
abundant
in
coal
measure
formations.
In
order
to
achieve
the
joint
exploitation
of
through
multilayers,
penetrating
fracturing,
achieving
crack
propagation
across
different
layer
interfaces,
was
used
increase
overall
permeability
The
true
triaxial
tests
were
conducted
investigate
natural
coal–rock
combination
with
using
supercritical
CO2
(ScCO2)
hydraulic
fracturing.
morphological
characteristics
within
after
fracturing
analyzed.
Meanwhile,
fracturing-induced
anisotropic
explored.
main
results
showed
that
(1)
compared
ScCO2
is
beneficial
cracks
crossing
interface
into
forming
a
complex
fracture
network.
(2)
After
parallel
perpendicular
bedding
plane
22.5
21.9
times
higher
than
before
respectively.
Compared
induced
larger
increase,
40.3
39.6
times,
(3)
ratio
2.01,
it
becomes
2.05
2.15,
addition,
both
sides
(along
plane)
an
evident
permeability.
indicate
brings
enhancement
rock–rock
Energy & Fuels,
Journal Year:
2024,
Volume and Issue:
38(10), P. 8688 - 8699
Published: April 30, 2024
Nanopores
play
a
crucial
role
in
the
storage,
desorption,
and
diffusion
of
coalbed
methane
within
coal.
This
study
aims
to
clarify
evolution
mechanism
nanopores
controlled
by
chemical
structure
coal
during
coalification.
By
conducting
low-pressure
CO2
N2
adsorption
experiments,
nanopore
six
distinct
samples
with
varying
ranks
was
identified.
Additionally,
characterized
through
13C
nuclear
magnetic
resonance
Raman
spectroscopies.
Through
comprehensive
analysis,
influenced
thoroughly
investigated.
The
results
show
that
coalification
(Ro
range
0.6–3.0%),
aliphatic
content
gradually
decreases,
while
aromatic
relatively
increases.
structures
become
more
ordered,
condensation
leads
an
increase
size
rings.
Due
influence
structure,
can
be
divided
into
three
stages.
In
first
stage
(0.6%
<
Ro
1.5%),
cleavage
side
chains
adjustment
orientation
lead
transformation
micropores
mesopores
second
(1.5%
2.0%),
strengthened
rings
third
(2.0%
3.0%),
most
oriented
undergo
significant
condensation,
leading
formation
many
These
findings
help
understand
control
on
provide
valuable
theoretical
insights
for
enhancing
extraction
efficiency.
