JPIChE 40 (1) 2012: : 79-81
Journal of Pakistan Institute of Chemical Engineers
Journal of
The Pakistan Institute of
Chemical Engineers
Vol. XXXX 2012
ISSN 1813-4092
journal homepage: www.piche.org.pk/journal
Investigating the Influence of Pressure and Temperature on
Malaysian Crude Oil Density and Viscosity for Improved Recovery
2
Muhammad Khurram Zahoor1*, Mohd. Nawi Derahman
Submitted: 18/11/2012, Accepted: 25/11/2012, Online: 06/12/2012
Abstract
Malaysia has great potential as a crude oil or fossil fuel producing country. To increase oil production, behavior
of Malaysian Crude Oil has been analyzed with reference to temperature and pressure variations. The effect of
these parameters on crude oil density and viscosity has been observed, to select the methodology to be adopted for
increased recovery by implementing enhanced oil recovery (EOR) project. Based on this study it has been
decided to further explore the feasibility of increasing reservoir pressure.
Keywords: Variations in density, enhanced oil recovery, Variations in viscosity
Introduction
Crude or fossil fuel is an efficient source of energy,
which is used to run automobiles, machineries in
the industry and to produce electricity etc., after
refining.
Crude oil is present beneath the earth in
formations/ reservoirs from which it is produced by
drilling wells [1-2]. Being one of the most important
source of energy, efforts have been made to increase
its production [3.5]. Density and viscosity are two
prime parameters which controls the flow of fluid in
the subsurface as well as at the surface [6-7]. In this
study, these parameters have been investigated for
an oil field with reference to change in temperature
and pressure, to have an in-depth analysis and to
opt for better option during future development of
the field for enhanced oil recovery.
Correlations for Oil Density and Viscosity
Density of crude oil under consideration in this
study can be expressed in the form of gas solubility
with the help of following correlation (under
isobaric conditions), developed by Zahoor et al [8].
(1)
ρ CO = 1.9 x 10−6 R s2 − 0.010876x R s + 47.3
So to analyze the effect of variation in pressure on
crude oil density under consideration, still a
correlation need to be developed, so in this study the
following correlation developed by Standing has
been used [9]:
ρo =
62.4γo + 0.0136R s γg
1.175
0.972 + 0.000147 [ Rs (
γo 0.5
) + 1.25 ( T− 460 ) ]
γg
(2)
Where, the amount of gas dissolved in oil can be
calculated by using the following equation [9]:
(3)
While the behavior of crude oil viscosity in this case
can be represented by combining a set of
correlations developed by Beggs et al [10]. for dead
(oil containing no gas) and live ( in which gas is
absorbed) oil. For dead oil, viscosity can be
calculated by using the following relationship [10]:
(4)
1
Department of Petroleum and Gas Engineering, University of Engineering and Technology, Lahore, Pakistan.
Faculty of Petroleum and Renewable Energy Engineering, Universiti Teknologi Malaysia, Johor Bahru, Malaysia.
Corresponding Author: Dr. Muhammad Khurram Zahoor ([email protected])
2
79
80
Journal of the Pakistan Institute of Chemical Engineers
Vol. XXXX
and for live oil or live crude oil, they proposed the
following correlation [10]:
(5)
Behavioral Analysis of Crude Oil
The adopted procedure can be explained with the
help of following steps, to analyze the behavior of
crude oil of concerned field having oil and gas of
specific gravity of 0.756 and 0.65, respectively:
1. Vary pressure values, while keeping
temperature constant.
2. Calculate gas solubility or gas-oil ratio.
3. Calculate crude oil density using equation (1).
4. Calculate crude oil viscosity using eq. (4) and
(5), where equation (5) gives the viscosity under
consideration.
Repeat steps from 2 to 4, by keeping the pressure
constant and varying the temperature values.
The study can be divided into two parts, i.e.,
analyzing the change in crude oil parameters under
consideration with reference to variations in
temperature under isobaric conditions and secondly
analyzing the said parameters by varying the
pressure under isothermal conditions.
Fig. 2: Behavior of crude oil viscosity with reference
to temperature variations
Figure (1) shows that as the temperature increases
density of crude oil (containing gas) also increases.
The figure also shows that initially the change in
density is negligible but as the temperature
increase from 600 oR to higher values, then the
abrupt change in density can be observed.
Similarly, the behavior of oil viscosity is shown in
figure (2). Figure (2), shows an almost linear and
inverse relationship between viscosity and
temperature, i.e., as the temperature increases, oil
viscosity decreases.
Results and Discussion
Case 1: Varying Temperature under isobaric
conditions
In this case temperature has been varied from 100
F (560 oR) to 390 oF (750 oR) in increments at a
constant pressure of 5000 psia. The obtained results
are shown in figures (1) and (2).
o
Case 2: Varying Pressure under isothermal
conditions
In this case pressure has been varied from 250 to
8000 psia at a constant temperature of 600 oR. The
obtained results show that as the pressure
increases, density of oil decreases (figure 3).
Similarly, the effect of variations in pressure on oil
viscosity can be shown with the help of figure (4):
Comparative Analysis
Fig. 1: Behavior of oil density with reference to
temperature variations
The results obtained for both cases show that
temperature has direct relationship with the oil
density and on the other hand pressure has inverse
relationship with oil density. While in case of
viscosity both parameters have inverse relationship
(figure 2 and 4).
2012
Muhammad Khurram Zahoor, Mohd. Nawi Derahman
81
injection wells and injecting water through them.
So, for further planning, increasing reservoir
pressure seems to be a better option and EOR
projects can be designed by giving this option a due
consideration.
References
Fig. 3: Effect of pressure on crude oil density
Fig. 4: Crude oil viscosity with reference to pressure
variations
Though, temperature and pressure have same
effect on oil viscosity but the magnitude of effect is
different. The change in oil viscosity is higher in
case of temperature variations as compared to the
later case.
1.
Ahmed, T., Reservoir Engineering Hand Book.
2nd. ed., Houston, TX.: Gulf Pub. Co (2000).
2.
Zolotukhin, A.B. and J.R. Ursin, Introduction
to Petroleum Reservoir Engineering., Oslo:
Hoyskolefort (2000).
3.
Yassin, A.A.M., Enhanced Oil Recovery in
Malaysia, in Offshore South East Asia Show:
Singapore (1988).
4.
Wan Nawawi Wan, M., et al., Application of
Improved and Enhanced Oil Recovery
Strategies in the Tapis Field, in SPE
International Improved Oil Recovery
Conference in Asia Pacific. Society of
Petroleum Engineers: Kuala Lumpur,
Malaysia (2005).
5.
Taber, J.J., F.D. Martin, and R.S. Seright,
EOR Screening Criteria Revisited - Part 1:
Introduction to Screening Criteria and
Enhanced Recovery Field Projects. SPE
Reservoir Engineering, 12(3): (1997).
6.
Ahmed, T., Hydrocarbon Phase Behavior.
Houston: Gulf Pub. Co (1989).
7.
Guo, B., W.C. Lyons, and A. Ghalambor,
Petroleum Production Engineering; a
Computer Assisted Approach: Elsevier Science
& Technology Books (2007).
8.
Zahoor, M.K. and M.N. Derahman, Developed
Correlation to Estimate the Malaysian Crude
Oil Density and Viscosity - A Preliminary
Study. Science International, (2012).
9.
Standing, M.B., Volumetric and Phase
behavior of Oil field Hydrocarbon system. 9th.
ed., Dallas: Society of Petroleum Engineers
(1981).
Conclusion and Recommendations
Based on this study, it has been observed that
increasing temperature of the reservoir can result
into high recovery or total production. But this
approach might have limitations and the level up to
which a temperature can be raised is also a point of
concern. While on the other side, increasing
reservoir pressure seems to be a better option for
the time being, which can be done by drilling
10. Beggs, H.D. and J.R. Robinson, Estimating the
Viscosity of Crude Oil Systems. SPE Journal of
Petroleum Technology, 1975. 27(9): (1975).