master thesis defence: density of oil-related systems at high pressures - experimental measurements...

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:

PresentaHon outline

IntroducHon – HPHT reservoirs –  Thesis scope –  Literature review

Density –  IntroducHon to density – Density measurement methods

PresentaHon outline HPHT density measurements

– U-‐tube basic principle –  CalibraHon procedure –  Experimental setup –  Experimental procedure

Density modeling Results and discussion Conclusion

HPHT reservoirs

(BakerHughes, 2005) (Belani & Orr, 2008)

Challenges of HPHT reservoirs

(Shadravan & Amani, 2012)

HPHT well summit, London, 2012

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

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).

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%

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%

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

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

Density measurement methods

•  Pycnometric densitometers

•  Hydrometers

•  Refractometer and index of refracHon densitometers

•  VibraHng tube densitometers

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)

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)

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

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

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)

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)

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.


(Paar, 2015)

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


(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.

CalibraHon procedure Pressure: 0.1 MPa -‐ 140 MPa Temperature: 5 °C -‐ 75 °C

Pressure: 0.1 Mpa Temperature: 5 °C -‐ 190°C

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

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

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

Anton Paar mPDS 5

(DTU laboratory)

SIKA digital pressure gauge Type P

(DTU laboratory)

Maximum Pressure 1500 bar Temperature effect ±0.002%.

(SIKA, 2015)

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

(DTU laboratory)

Teledyne Isco 260D syringe pump

(DTU laboratory)

Overall experimental setup

(DTU laboratory)

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.

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.

Performing a measurement

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.

Anton Paar mPDS 5

(DTU laboratory)

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

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).

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

Perio

d (μs)

Temperature (°C)

2655

2665

2675

2685

2695

2705

2715

2725

2735

0 200 400 600 800 1000 1200 1400 1600

Perio

d (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


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)(1

05s-‐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


-‐0,25

-‐0,2

-‐0,15

-‐0,1

-‐0,05

0

0,05

0,1

0,15

0,2

0 50 100 150 200

RelaTv

e de

viaT

on (%

)

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 Re

laTv

e de

viaT

on (%

)

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.

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)


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


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

RelaTv

e de

viaT

on (%

)

Temperature (°C)

-‐0,2

-‐0,1

0,0

0,1

0,2

0,3

0,4

0 100 200 300 400 500 600 700

RelaTv

e de

viaT

on (%

) Pressure (bar)

AAD of 0.17%.


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)


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


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

RelaTv

e de

viaT

on (%

)

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

RelaTv

e de

viaT

on (%

)

Pressure (bar)

Audonnet & Padua (2004) Canet et al. (2002)

AAD = 0.30% AAD = 0.19%


Parameters obtained in the Tait equaHon with the results from Audonnet & Pádua (2004) (xmethane = 0.799) and our experimental results (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


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

RelaTv

e de

viaT

on (%

)

Temperature (°C)

Audonnet & Padua (2004)

-‐14

-‐12

-‐10

-‐8

-‐6

-‐4

-‐2

0 0 100 200 300 400 500 600 700

RelaTv

e de

viaT

on (%

)

Pressure (bar)

Audonnet & Padua (2004)

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/m

3 )

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

Density modeling

0

5

10

15

20

25

SRK PR PC SAFT SBWR

Xmethane = 0.227 Xmethane = 0.6017 Xmethane = 0.8496 Decane

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%.

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.

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

be\er results but on the other hand the cubic PR performed be\er than the non-‐cubic SBWR for some of the mixtures, is an indicator that further study is necessary.

Density modeling

0

5

10

15

20

25

SRK PR PC SAFT SBWR

Xmethane = 0.227 Xmethane = 0.6017 Xmethane = 0.8496 Decane

Thank you for your Hme!

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.

Viscosity

(Paar, 2015)

Highest viscosity m e a s u r em 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

master thesis defence: density of oil-related systems at high pressures - experimental measurements...

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