The need for more energy recourses in combination with the gradual decrease of easily accessible hydrocarbons has led the industry to exploit deeper reservoirs, which are associated with higher pressures and temperatures. The correct identification of the physical properties of the reservoir hydrocarbons, such us density, is a significant parameter for estimating the amount of recourses in place and forecasting the production. Therefore in this work the measurement of the density of the binary system methane - n-decane for four different compositions (xmethane = 0, 0.227, 0.6016, 0.8496) and under a wide range of pressure (up to 1400 bar) and temperature (up to 190 °C) was carried out with the use of an Anton Paar DMA-HPM densimeter. The calibration of the DMA-HPM densimeter was performed for pressures up to 140 MPa (1400 bar) and temperatures up to 190 °C (463.15 K) with a modified Lagourette equation proposed by Comuñas et al and for the validation of the apparatus, the density of n-decane was measured. Finally a comparison between two cubic EoS (SRK and PR) and two non-cubic EoS (PC SAFT and SBWR) was performed.

1. Density of Oil-related Systems at High Pressures
Experimental measurements of HPHT density
Post
Doc.
Teresa
Regueira
Muñiz
Vasos
Vasou
s131031
DEPARTMENT
OF
CHEMISTRY
MASTER
THESIS
DEFENCE
Senior
researcher
Wei
Yan
Supervisors:

2. PresentaHon
outline
IntroducHon
– HPHT
reservoirs
– Thesis
scope
– Literature
review
Density
– IntroducHon
to
density
– Density
measurement
methods

3. PresentaHon
outline
HPHT
density
measurements
– U-­‐tube
basic
principle
– CalibraHon
procedure
– Experimental
setup
– Experimental
procedure
Density
modeling
Results
and
discussion
Conclusion

4. HPHT
reservoirs
(BakerHughes,
2005)
(Belani
&
Orr,
2008)

5. Challenges
of
HPHT
reservoirs
(Shadravan
&
Amani,
2012)
HPHT
well
summit,
London,
2012

6. Thesis
scope
Correct
idenHficaHon
of
the
physical
properHes
of
the
reservoir
hydrocarbons
Be^er
understanding
of
the
behaviour
of
the
hydrocarbon
reservoir
fluids
More
precise
esHmaHon
of
the
amount
of
recourses
in
place
Be^er
producHon
forecasHng
Minimized
technical
risks
PosiHve
revenue

7. Major
tasks
• Literature
review
of
the
exisHng
relevant
data
on
density
of
alkane
binary
mixtures
under
HPHT.
• CalibraHon
of
the
densimeter
for
pressures
up
to
1400
bar
and
temperatures
up
to
190
°C.
• ValidaHon
of
the
apparatus
through
the
use
of
n-­‐decane.
• Measurement
of
the
density
of
the
binary
system
methane
-­‐
n-­‐
decane
for
three
different
composiHons
and
under
a
wide
range
of
pressure
and
temperature.
• A
comparison
of
two
cubic
EquaHons
of
State
(EoS)
(Soave–
Redlich–Kwong
and
Peng–Robinson)
with
two
non-­‐cubic
EoS
(Perturbed
Chain
StaHsHcal
AssociaHng
Fluid
Theory
and
Benedict–Webb–Rubin).

8. Literature
Audonnet
&
Padua
(2004):
• Anton
Paar
DMA
60
densimeter
• Binary
mixture
methane
–
n-­‐decane
• xmethane
=
0,
0.227,
0.410,
0.601,
0.799
• Temperatures
from
30
°C
to
120
°C
.
• Pressures
from
200
bar
to
650
bar
(extrapolated
up
to
1400
bar)
• Standard
deviaHon
with
literature
equal
to
0.17%
and
0.3%

9. Literature
Canet
et
al.
(2002):
• Binary
mixture
methane
–
n-­‐decane
• xmethane
=
0.3124,
0.4867,
0.6,
0.7566,
0.9575
• Temperatures
from
20
°C
to
100
°C.
• Pressures
from
200
bar
to
650
bar
(extrapolated
up
to
1400
bar
• AAD
with
literature
equal
to
3.3%
and
7.3%

10. Density
Density
is
a
fundamental
parameter
that
contributes
to
the
characterizaHon
of
the
product
and
is
defined
as
the
exact
mass
of
a
solid,
gas
or
liquid
that
is
occupying
a
specific
volume.
The
most
common
symbol
for
density
is
the
Greek
le^er
ρ
and
it
can
be
mathemaHcally
defined
as:
ρ
=
m/V
(kg/m3).
where
m
is
the
mass
and
V
is
the
volume

11. Density
Pressure
and
temperature
are
two
important
parameters
that
affect
density.
An
increase
on
pressure
will
cause
an
increase
on
density
whereas,
on
the
other
hand,
for
most
materials
the
temperature
affects
density
inversely
proporHonal.
Temperature
Density
Pressure
Density

12. Density measurement methods
• Pycnometric
densitometers
• Hydrometers
• Refractometer
and
index
of
refracHon
densitometers
• VibraHng
tube
densitometers

13. Pycnometric
densitometers
(Eren,
1999)
• Weighing of the mass of the
empty pycnometer.
• Determination of the volume
with the use of distilled water
• Weighing again to get the mass
of the water.
• Repeat with the liquid of the
unknown density to determine its
mass and its volume.
• The density of the unknown
liquid is calculated as:
Precision
Can
also
measure
specific
gravity
User
depended
Slow
High
cost
(scale,
lab)

14. Hydrometers
Scale
F l u i d
vessel
We i g h t
bulb
Consists
of
a
floaHng
glass
body,
with
a
cylindrical
stem
with
a
scale
and
a
bulb
filled
with
metal
weight.
The
measurement
procedure
is
very
simple
since
it
only
involves
the
immersion
of
the
hydrometer
in
the
sample
and
the
reading
of
the
density
directly
from
the
scale.
The
deeper
the
hydrometer
sinks
the
less
dense
the
sample
is.
The
principle
used
for
determining
the
density
with
the
hydrometer
is
buoyancy.
Low
cost
Simple
Fast
Traceable
to
internaHonal
standards
User
depended
Need
temperature
correcHon
Require
large
sample
volume
(100
mL)
(Eren,
1999)

15. Refractometer and index of refraction
densitometers
(Eren,
1999)
Describes
how
much
of
the
light,
is
refracted
when
entering
a
sample
where
c
is
the
speed
of
light
in
vacuum
and
u
is
the
velocity
of
light
in
a
medium
Index
of
refracHon
Consists
of
a
transparent
cell
that
the
liquid
or
gas
flows
through,
a
laser
beam
that
passes
through
the
cell
and
the
sample
and
is
refracted
with
an
angle
and
a
sensor.
The
angle
of
refracHon
depends
on
the
shape,
size
and
thickness
of
the
container
and
on
the
density
of
the
sample.
An
accurate
measurement
of
the
posiHon
of
the
beam
and
the
refracHon
angle
can
relate
to
the
sample’s
density.
n
=
c/u

16. Vibrating tube densitometers
The vibrating tube densitometer is based on the principle that
every fluid has a unique natural frequency.
where
K
is
the
elasHcity
constant
of
the
body,
m
is
the
mass
of
the
body
containing
the
fluid,
ρ
is
the
fluid
density,
V
is
the
volume
of
the
body
and
τ
is
the
oscillaHon
period.
High
accuracy
and
repeatability
Very
fast
Li^le
sample
volume
required
Possible
dynamic
influence
of
viscosity
on
the
results
for
viscous
samples

17. Vibrating tube densitometers
The single tube has pressure
losses and some obstruction
on the natural flow.
The two-tube densitometer is
designed in a way that the two
tubes are vibrating in an antiphase,
which provides higher accuracy.
(Eren,
1999)

18. U-tube basic principle
A
hollow
U-­‐shaped
tube
is
filled
with
the
sample
fluid
and
is
subjected
to
an
electromagneHc
force
and
is
excited
into
periodic
oscillaHon.
The
frequency
as
a
funcHon
of
Hme
is
recorded
and
a
sin-­‐wave
of
a
certain
period
and
amplitude
is
created.
(Paar,
2015)

19. U-tube basic principle
(Paar,
2015)
AlternaHng
voltage
is
sent
through
the
electric
coil
on
the
tube,
which
creates
an
alternaHng
magneHc
field.
The
magnet
on
the
tube
reacts
to
the
alternaHng
current
and
as
a
result
an
excitaHon
is
generated.
The
frequency
of
the
magnet’s
oscillaHon
that
is
caused
is
measured
with
an
amplifier.

20. U-tube basic principle
(Paar,
2015)

21. U-tube basic principle
Hans Stabinger studied the relation between the period of
oscillation and the density and found a way to implement it
mechanically. To achieve this, Stabinger introduced two,
unique
for
each
instrument,
adjustment constants namely A
and B described as:
ρ
=
A
.
τ2
-­‐
B

22. U-tube basic principle
(Paar,
2015)
Because the density of the water and the air are known the
adjustment constants A and B can be calculated as they
define a straight line in the graph. The instrument measures
the period of oscillation of the sample and then applies that
value to the adjustment line and converts it to the
corresponding density.

23. CalibraHon
procedure
Pressure:
0.1
MPa
-­‐
140
MPa
Temperature:
5
°C
-­‐
75
°C
Pressure:
0.1
Mpa
Temperature:
5
°C
-­‐
190°C

24. CalibraHon
procedure
Pressure:
0.1
Mpa
–
140
MPa
Temperature:
100
°C
-­‐
150°C
Pressure:
1
Mpa
–
140
MPa
Temperature:
190°C
&
Pressure:
0.1
Mpa
Temperature:
190°C

25. Experimental setup
Anton Paar External Measuring Cell DMA-HPM
(DTU
laboratory)
(Paar,
2015)
Measuring range
Density 0 to 3 g/cm3
Pressure 0 to 1400 bar
Temperature -10 to +200 °C
Accuracy
Density Up to 0.001 g/cm3
Error 0.001 to 0.0001 g/cm3

26. PolyScience advanced programmable temperature
controller with Swivel 180™ Rotating Controller
(DTU
laboratory)
Maximum Temperature 200°C
Minimum Temperature -20°C
Temperature Stability ±0.01°C

27. Anton
Paar
mPDS
5
(DTU
laboratory)

28. SIKA digital pressure gauge Type P
(DTU
laboratory)
Maximum Pressure 1500 bar
Temperature
effect ±0.002%.
(SIKA,
2015)

29. Edwards E2M1.5 two-stage oil sealed rotary vane
pump and Edwards Active Digital Controller (ADC)
(DTU
laboratory)

30. Teledyne Isco 260D syringe pump
(DTU
laboratory)

31. Overall experimental setup
(DTU
laboratory)

32. Apparatus cleaning procedure
Cleaning
of
the
densitometer
and
the
fluid
piston
cylinder:
• Remove
the
already
inserted
sample
with
moving
the
fluid
piston
cylinder
back
and
forth
several
Hmes.
• Rinse
with
toluene
(strong
organic
solvent,
ideal
for
cleaning
petroleum
mixtures).
• Rinse
with
ethanol
(can
remove
toluene
and
is
volaHle
and
can
evaporate
without
residue).
• Dry
out
with
pressurized
air
and
evacuate
the
system
for
an
hour
in
75
°C
and
then
lep
under
vacuum
over
night
at
ambient
temperature.
Cleaning
of
the
mixture
cylinder
and
peripheral
lab
equipment:
• All
the
parts
of
the
cylinder
and
peripheral
equipment
were
rinsed
with
the
cleaning
fluids
and
dried
out
with
pressurized
air.
The
cylinder
was
then,
evacuated.

33. Mixture preparation
ρdec
=
726.55
kg/m3
at
Tambient
=
24.97
°C
(Lemmon
&
Span,
2006)
(DTU
laboratory)
• n-­‐decane
was
transferred
with
the
use
of
a
50
mL
bure^e
with
readability
±
0.01
mL.
• Methane
was
transferred
from
the
gas
pressurized-­‐bo^le
into
the
gas
cylinder.
• The
gas
cylinder
was
placed
on
a
balance
(readability
0.001g)
and
the
methane
mass
transferred
in
the
mixture
cylinder
was
read
from
the
balance.

34. Performing a measurement

35. Performing a measurement
• Temperature
set
on
the
PolyScience
advanced
programmable
temperature
controller.
• The
first
pressure
step
was
manually
reached.
• The
values
for
the
data
transfer
and
the
slope
stability
were
added
by
the
user.
• IniHate
the
measurement
from
the
Microsop
Excel®
spreadsheet
provided
by
Anton
Paar.
• Aper
the
recording
process
ended,
the
user
could
access
the
recorded
values
from
the
data
spreadsheet
of
the
Microsop
Excel®
tool.
• Finally,
the
pressure
was
increased
and
aper
all
the
pressure
steps
were
measured
the
same
procedure
was
repeated
for
the
remaining
temperatures.

36. Anton
Paar
mPDS
5
(DTU
laboratory)

37. Density
modelling
Cubic
EoS
Non-­‐Cubic
EoS
Soave–Redlich–Kwong
(SRK)
Perturbed
Chain
StaHsHcal
AssociaHng
Fluid
Theory
(PC-­‐SAFT)
Peng–Robinson
(PR)
Soave
modified
Benedict–Webb–
Rubin
(SBWR)
InteracHon
parameters
for
the
methane
–
n-­‐decane
binary
mixture
CriHcal
parameters
of
methane
and
n-­‐decane

38. Results
and
discussion
Densimeter
calibraHon
and
validaHon
results
• The
oscillaHon
period
of
the
tube
when
filled
with
water
was
measured.
• The
oscillaHon
period
of
the
evacuated
tube
was
measured.
• The
density
of
water
was
taken
from
NIST
that
uses
the
EoS
from
Wagner
and
Pruss
(2002)
• The
density
of
n-­‐dodecane
was
taken
from
NIST
that
uses
the
EoS
from
Lemmon
&
Huber
(2004).
• The
oscillaHon
period
of
n-­‐dodecane
was
measured
in
a
previous
work
(Chasomeris
et
al.,
2015).

39. Densimeter
calibraHon
and
validaHon
results
2580
2590
2600
2610
2620
2630
2640
2650
2660
0
20
40
60
80
100
120
140
160
180
200
Period
(μs)
Temperature
(°C)
2655
2665
2675
2685
2695
2705
2715
2725
2735
0
200
400
600
800
1000
1200
1400
1600
Period
(μs)
Pressure
(bar)
5
°C
25
°C
50
°C
75
°C
100
°C
150
°C
190
°C
Period
of
the
evacuated
densimeter
for
temperatures
from
5°C
to
190°C
Water
measured
period
for
temperatures
from
5°C
to
190°C
and
pressures
from
1
bar
to
1400
bar

40. Densimeter
calibraHon
and
validaHon
results
2,26
2,28
2,30
2,32
2,34
2,36
2,38
2,40
2,42
2,44
0
50
100
150
200
A
(T)
(10^9kg
s-­‐1
m-­‐3)
Temperature
(°C)
1,41
1,42
1,43
1,44
1,45
1,46
1,47
1,48
1,49
1,5
0
200
400
600
800
1000
1200
1400
A(T)/B(T,p)(105s-­‐2)
Pressure
(bar)
5°C
25°C
50°C
75°C
100°C
150°C
190°C
(Segovia
et
al.
2009)
CharacterisHc
parameter
A(T)
and
the
raHo
between
parameter
A(T)
and
parameter
B(T,p)
for
temperatures
from
5°C
to
190°C

41. Densimeter
calibraHon
and
validaHon
results
-­‐0,25
-­‐0,2
-­‐0,15
-­‐0,1
-­‐0,05
0
0,05
0,1
0,15
0,2
0
50
100
150
200
RelaTve
deviaTon
(%)
Temperature
(°C)
Lemmon
&
Span
(2006)
AAD
=
0.08%.
-­‐0,25
-­‐0,2
-­‐0,15
-­‐0,1
-­‐0,05
0
0,05
0,1
0,15
0,2
0
200
400
600
800
1000
1200
1400
1600
RelaTve
deviaTon
(%)
Pressure
(bar)
Lemmon
&
Span
(2006)
RelaHve
deviaHons
between
the
experimental
density
values
of
n-­‐decane
and
the
data
from
Lemmon
&
Span
(2006)
as
a
funcHon
of
temperature
and
pressure.

42. Mixture methane – n-decane (xmethane = 0.227)
A
correlaHon
with
the
use
of
the
Tait
equaHon
(Dymond
&
Malhotra,
1988)
was
performed.
Parameters
obtained
in
the
Tait
equaHon
with
the
results
from
Audonnet
&
Pádua
(2004)
(xmethane
=
0.227)
and
our
experimental
results
(xmethane
=
0.227)

43. Mixture methane – n-decane (xmethane = 0.227)
Surface
ρ(T,p)
for
our
experimental
results
(xmethane
=
0.227)
and
the
results
from
Audonnet
&
Pádua
(2004)
(xmethane
=
0.227
)for
the
mixture
methane
–
n-­‐decane

44. Mixture methane – n-decane (xmethane = 0.227)
RelaHve
deviaHons
between
the
experimental
density
values
of
the
mixture
methane
–
n-­‐decane
(xmethane
=
0.227)
and
the
data
from
Audonnet
&
Paduá
(2004)
(xmethane
=
0.227)
as
a
funcHon
of
temperature
and
pressure
-­‐0,2
-­‐0,1
0,0
0,1
0,2
0,3
0,4
0
20
40
60
80
100
120
RelaTve
deviaTon
(%)
Temperature
(°C)
-­‐0,2
-­‐0,1
0,0
0,1
0,2
0,3
0,4
0
100
200
300
400
500
600
700
RelaTve
deviaTon
(%)
Pressure
(bar)
AAD
of
0.17%.

45. Mixture methane – n-decane (xmethane = 0.6017)
Parameters
obtained
in
the
Tait
equaHon
with
the
results
from
Audonnet
&
Pádua
(2004)
(xmethane
=
0.601),
our
experimental
results
(xmethane
=
0.6017)
and
those
from
Canet
et
al.
(2002)
(xmethane
=
0.6)

46. Mixture methane – n-decane (xmethane = 0.6017)
Surface
ρ(T,p)
for
our
experimental
results
(xmethane
=
0.6017)
and
the
results
from
Audonnet
&
Pádua
(2004)
(xmethane
=
0.601)
for
the
mixture
methane
–
n-­‐decane

47. Mixture methane – n-decane (xmethane = 0.6017)
RelaHve
deviaHons
between
the
experimental
density
values
of
the
mixture
methane
–
n-­‐decane
(xmethane
=
0.6017),
the
data
from
Audonnet
&
Paduá
(2004)
(xmethane
=
0.601)
and
Canet
et
al.
(2002)
(xmethane
=
0.6)
as
a
funcHon
of
temperature
and
pressure
-­‐0,4
-­‐0,2
0,0
0,2
0,4
0,6
0,8
1,0
0
20
40
60
80
100
RelaTve
deviaTon
(%)
Temperature
(°C)
Audonnet
&
Padua
(2004)
Canet
et
al.
(2002)
-­‐0,4
-­‐0,2
0,0
0,2
0,4
0,6
0,8
1,0
0
200
400
600
800
1000
1200
1400
RelaTve
deviaTon
(%)
Pressure
(bar)
Audonnet
&
Padua
(2004)
Canet
et
al.
(2002)
AAD
=
0.30%
AAD
=
0.19%

48. Mixture methane – n-decane (xmethane = 0.8496)
Parameters
obtained
in
the
Tait
equaHon
with
the
results
from
Audonnet
&
Pádua
(2004)
(xmethane
=
0.799)
and
our
experimental
results
(xmethane
=
0.8496)

49. Mixture methane – n-decane (xmethane = 0.8496)
Surface
ρ(T,p)
for
our
experimental
results
(xmethane
=
0.8496)
and
the
results
from
Audonnet
&
Pádua
(2004)
(xmethane
=
0.799)
for
the
mixture
methane
–
n-­‐decane

50. Mixture methane – n-decane (xmethane = 0.8496)
RelaHve
deviaHons
between
the
experimental
density
values
of
the
mixture
methane
-­‐
n-­‐decane
(xmethane
=
0.8496)
and
the
data
from
Audonnet
&
Paduá
(2004)
(xmethane
=
0.799)
as
a
funcHon
of
temperature
and
pressure
AAD
=
11.11%
-­‐14
-­‐12
-­‐10
-­‐8
-­‐6
-­‐4
-­‐2
0
0
20
40
60
80
100
120
RelaTve
deviaTon
(%)
Temperature
(°C)
Audonnet
&
Padua
(2004)
-­‐14
-­‐12
-­‐10
-­‐8
-­‐6
-­‐4
-­‐2
0
0
100
200
300
400
500
600
700
RelaTve
deviaTon
(%)
Pressure
(bar)
Audonnet
&
Padua
(2004)

51. Density
as
a
funcHon
of
pressure
for
all
composiHons
at
5
°C
and
190
°C
300
400
500
600
700
800
300
500
700
900
1100
1300
Density
(kg/m3)
Pressure
(bar)
n-­‐decane
at
5
°C
Xmethane=0.227
at
5
°C
Xmethane=0.6017
at
5
°C
Xmethane=0.8496
at
5
°C
n-­‐decane
at
190
°C
Xmethane=0.227
at
190
°C
Xmethane=0.6017
at
190
°C
Xmethane=0.8496
at
190
°C

52. Density modeling
0
5
10
15
20
25
SRK
PR
PC
SAFT
SBWR
Xmethane
=
0.227
Xmethane
=
0.6017
Xmethane
=
0.8496
Decane

53. Conclusion
• The
validaHon
of
the
apparatus
through
n-­‐decane
was
successful.
The
results
were
compared
with
the
data
from
NIST
and
they
were
in
good
agreement
with
an
AAD
of
0.08%.
• For
the
mixture
with
a
composiHon
of
methane
xmethane
=
0.227
and
aper
a
correlaHon
with
the
Tait
equiHon
the
experimental
data
were
compared
with
the
results
obtained
from
Audonnet
&
Pádua
with
an
AAD
of
0.17%.
• The
mixture
under
study
with
a
composiHon
of
methane
xmethane
=
0.6017
were
again
correlated
with
the
Tait
equaHon
and
compared
with
the
results
from
Audonnet
&
Pádua
with
an
AAD
of
0.30%
and
with
those
from
Canet
et
al.
(2002)
with
an
AAD
of
0.19%.

54. Conclusion
• The
mixture
with
a
mole
fracHon
of
methane
xmethane
=
0.8496
was
compared
with
the
results
obtained
from
Audonnet
&
Pádua
(2004)
for
their
mixture
with
methane
mole
fracHon
xmethane
=
0.799.
The
experimental
results
have
an
AAD
of
11.11%.
A
high
negaHve
deviaHon
like
this
was
expected
because
of
the
different
methane
mole
fracHon
in
the
two
mixtures.
• In
general,
the
method
used
under
this
work
can
be
considered
successful
since
the
results
for
the
pure
n-­‐decane
and
the
binary
mixture
are
in
good
agreement
with
those
from
the
literature.

55. Conclusion
• PC
SAFT
was
the
one
that
performed
be^er
with
AADs
lower
than
1.2%.
The
SRK,
on
the
other
hand,
showed
very
high
deviaHons
between
10%
and
20%.
• For
the
pure
n-­‐decane
and
the
mixture
with
methane
mole
fracHon
xmethane
=
0.227
the
non-­‐cubic
equaHons
performed
much
be^er
with
lower
deviaHons.
• The
fact
that
on
the
one
hand
the
non-­‐cubic
EoS
showed
beer
results
but
on
the
other
hand
the
cubic
PR
performed
beer
than
the
non-­‐cubic
SBWR
for
some
of
the
mixtures,
is
an
indicator
that
further
study
is
necessary.

56. Density modeling
0
5
10
15
20
25
SRK
PR
PC
SAFT
SBWR
Xmethane
=
0.227
Xmethane
=
0.6017
Xmethane
=
0.8496
Decane

57. Thank
you
for
your
Hme!

59. Viscosity
(Paar,
2015)
FricHon
between
the
fluid
and
the
tube
The
oscillaHon
period
of
the
tube
is
influenced
by
viscosity.
High
viscous
sample
will
give
a
density
over-­‐reading.

60. Viscosity
(Paar,
2015)
Highest
viscosity
m e a s u r e m e n t
from
Canet
et
al.
η
=
1.7
mPa.s
for
xmethane=0.3
and
T = 2 0
° C
a n d
P=140
MPa