A Laboratory Study to Investigate CO2 Potential to
Mobilize Paleo Oil
Authors: Dr. Ahmed A. Al-Eidan, Xianmin Zhou, Dr. Hyung T. Kwak and Dr. Sunil L. Kokal
ABSTRACT
All reservoirs contain a transition zone below the oilwater contact (OWC), which varies in thickness depending on the reservoir rock properties. In some
reservoirs that have undergone geological and hydrodynamic titling, there could be an additional, sometimes
significant, residual oil zone (ROZ) below the transition
zone. This zone is sometimes referred to as the “paleo”
oil zone and may contain significant quantities of hydrocarbons. Traditionally, this has not received much
attention as its oil is immobile and does not normally
produce through primary and secondary recovery
methods; however, paleo oil has the potential to be
mobilized by carbon dioxide (CO2) injection.
The objective of this study is to show the ability of
CO2 injection to mobilize paleo oil in the ROZ. Different
laboratory experiments on actual reservoir sponge cores
from wells intersecting the ROZ have been conducted at
reservoir conditions. The study includes static CO 2
saturation (pressure-volume-temperature (PVT) cell) and
dynamic CO2 coreflooding experiments, and nuclear
magnetic resonance (NMR) analysis. The mobility of
paleo oil by CO2 flooding was investigated using both
static and dynamic CO2 injection experiments on sponge
cores containing paleo oil. The static experiments
showed, through images and videos, how the CO2 can
mobilize the paleo oil in the cores. The coreflood experiments showed the potential to mobilize the original oil in
cores (OOIC) from these two wells intersecting the ROZ.
It was found that CO2 soaking is a critical factor to
mobilize oil because it allowed more time for the CO2 to
interact with the available components. Core samples
were further analyzed microscopically using NMR
analysis (before and after CO2) to complement coreflood
interpretations. NMR showed the exact places in the
core where the oil was mobilized by CO2 and the type of
components extracted after the experiments (mostly
intermediate).
INTRODUCTION
All reservoirs have a transition zone below the oil-water
contact (OWC), Fig. 1. The oil saturation below the OWC
falls rapidly in the transition zone. This transition zone is
generally a few feet thick and its thickness is controlled
by capillary forces and the wettability behavior
Fig. 1. Definition of TZ and ROZ.
of the rock. A reservoir may flow some oil, but mostly
water, when perforated in the transition zone.
In some circumstances, primarily related to hydrological or geological conditions, the original oil zone can
be tilted and invaded by water. This creates a transition
zone that exists right below the current OWC and the
free water level (FWL), and a residual oil zone (ROZ) or
the paleo oil zone that exists between the FWL and the
paleo FWL. The ROZ produces only water. The oil in the
ROZ is immobile and cannot usually be produced by
primary or secondary recovery means. The oil saturations in the ROZ are generally similar to the residual oil
saturation in the swept zone of a waterflood. The difference, however, comes from the origins of the oil. The
prefix “paleo” comes from a Greek adjective meaning
“old.” This gives a clear distinction between this oil and
the residual oil after waterflood. This oil is created after
structural changes, e.g., uplift had taken place and the
oil column was invaded by water. Depending on the
degree and extent of titling or uplifting, a reservoir can
have a large ROZ that may contain significant quantities
of oil.
The industry experience on recovery from the ROZ
is limited with only a few studies reported in the literature; mainly in the Permian Basin, located in west Texas.
Consequently, the hydrocarbon resource in west Texas
ROZ rivals that in the main pay zone (MPZ). It is
believed that the ROZ in west Texas fields was created
after the reservoir had reached its spill point and
geological structural changes took place. There are
three proposed geological mechanisms that created this
large ROZ in the west Texas fields: Reservoir tilting that
SAUDI ARAMCO JOURNAL OF TECHNOLOGY
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caused oil to leak from the eastern end, water invasion
from the Rio Grande rift, and/or seal breaches that
1, 2
caused oil to leak out of structure . As a result, five
carbonate formations in the Permian Basin showed
evidence of significant paleo oil reserves in the ROZ:
1. Northern Shelf: Wasson (Denver unit and Bennett
Ranch unit)
2. North Central Basin platform (San Andres/Grayburg
formation): Seminole unit
3. South Central Basin platform (San Andres/Grayburg
formation)
4. Horseshoe Atoll: Kelly-Snyder (SACROC) and Salt
Creek
5. Eastern New Mexico: San Andres
Research studies focusing on ROZ is limited, most
of the studies found in the literature focus on the
transition zone. This further indicates the difficulty to
fundamentally study and simulate the ROZ in the
laboratory. The inability to flow this zone during primary
and secondary production poses the challenge to
capture representative samples for such studies. Skauge
3
and Surguchev (2000) compared carbon dioxide (CO2)
injection to recover paleo oil to flue and hydrocarbon
gases. The study used 2D and 3D sector models to
simulate down dip gas injection with vertical and
horizontal wells. The results of the simulation models
showed that CO2 injection has the potential to produce
paleo oil in the transition zone by vaporization and the
swelling of the oil. The simulation results also showed
that CO2 is far more efficient (6 to 8 times higher) than
flue and hydrocarbon gases even at immiscible conditions with a potential recovery of 50% of remaining oil in
place. Subsequently, high water production (60% to 70%
water cut) is expected before the first oil and that can be
mitigated by injecting up dip and the use of horizontal
wells.
1
Koperna et al. (2006) defined the distinction
between the transition zone and ROZ; and discussed
four pilot projects targeting ROZ. Two of the projects are
included in the Wasson oil field, one in the Seminole San
Andres unit, and one in Salt Creek. All projects confirmed the viability of CO2 enhanced oil recovery (EOR)
to produce transition zone residual oil. Different development strategies were evaluated for the fields using
reservoir simulation; including selectively producing the
top portion of the transition zone and simultaneously
producing the transition zone and the MPZ. It was found
that simultaneously completing the transition zone and
MPZ is a more viable option than selectively completing
the transition zone. The estimated recoverable reserves,
in both the San Andres and Canyon Reef formations in
the Permian Basin, are 12 billion barrels (bbl) out of the
31 billion bbl transition zone resource. Melzer et al.
2
(2006) discussed the origins of the ROZ and examined
different types of ROZ sources.
The main sources covered in the study are basin
uplift or subsidence, breached seals, and flow hydrodynamic alterations. The study defines the basin uplift or
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subsidence as a gravity dominated shift. This type of
ROZ can translate to significant amounts of trapped oil,
especially if the field has a large lateral extent. The
breached seals of the ROZ comprises of oil that did not
escape during a previous breach in the reservoir seal.
The containment of the oil is a result of a reservoir reseal
after geochemical and/or biological processes. The most
common and significant source of ROZ is a result of
altered hydrodynamic conditions. These changes occur
after an uplift of the regional trapping formation. The
Permian Basin (San Andres formation) and the
Panhandle and Hugoton fields are examples of such
ROZs. Different ROZ development examples were also
presented in this study, all at an oil price of $15 to
$20/bbl at the time and still producing economically (at
the time the article was written). The article also showed
a sensitivity study on parameters that can affect the
formation of the ROZ. Examples include aquifer flow
rate, horizontal permeability and kv/kh.
This article focuses on the potential of CO2 to
mobilize paleo oil by monitoring the produced oil vs.
remaining oil of the original oil in core (OOIC). It utilizes
a high-pressure/high temperature pressure-volumetemperature (PVT) cell for visualization and coreflooding
experiments to simulate static and dynamic injection
conditions. The results of these experiments are compared to nuclear magnetic resonance (NMR) analysis to
confirm the amounts of oil mobilized after the CO2 flood
and qualitatively determine the type of oil mobilized.
NMR detects all of the hydrogen atoms that exist in the
reservoir fluids, including water, oil and gas in situ
4, 5
without destroying the sample . Therefore, it has been
selected as a method of choice to monitor the movement
of fluids inside the rock samples before and after various
types of CO2 coreflooding experiments.
EXPERIMENTAL WORK
Fluids and Rock Properties
Brines. In this study, two types of brines were used, the
field connate water and seawater. The brines were only
used when investigating the mobility of MPZ oil for
comparison with ROZ paleo oil. The components of both
brines are listed in Table 1. The total dissolved solids of
field connate water and seawater are 213,734 ppm and
57,670 ppm, respectively. The densities and viscosities
of these brines at ambient and reservoir conditions of a
Field Connate
Water (g/L)
150.446
Seawater
(g/L)
41.041
CaCl2 2HO
69.841
2.384
.
MgCl2 6H2O
20.396
17.645
Na2SO4
0.518
6.343
NaHCO3
0.487
0.165
Component
NaCl
.
Table 1. Recipes of field connate water and seawater
Reservoir Temperature (102 °C)
Fluids
Room Temperature (25 °C)
Density (g/cc)
Viscosity (cP)
Density (g/cc)
Viscosity (cP)
Field Connate Water
1.0906
0.727
1.1462
1.530
Seawater
1.0018
0.502
1.0385
1.406
Crude Oil A
0.823
2.496
0.881
20.512
Crude Oil B
0.802
1.469
0.837
5.876
Table 2. Fluid properties
pressure of 3,200 psi and temperature of 102 °C are
listed in Table 2.
Crude oil. Two oils were studied, paleo oil, which
already exists in the core samples taken from Fields A
and B, and a dead MPZ crude oil sample from the same
fields. The filtration of dead crude oil was conducted with
5 µm filter at ambient conditions. The density and
viscosity of crude oil, seawater, and field connate water
at room and reservoir condition are also listed in Table 2.
CO2. The CO2 used for the laboratory corefloods is 99.6
mol% pure and injected above the supercritical conditions in this study — experimental temperature and
pressure were above its critical point, 88 °F and 1,074
psi. The density and viscosity of supercritical CO 2 at test
conditions of 3,200 psi and 102 °C are 0.5337 g/cc and
0.042 cP, respectively.
Core plugs. The core plugs used to study paleo oil
mobilization were drilled from sponge cores taken from
two fields, Fields A and B. The cores are used in their
native state targeting the available paleo oil as shown on
the logs. Other experiments to study dead oil recovery
were taken from the same field’s MPZ for comparison.
The selected MPZ cores had intentionally comparable
properties to ROZ cores, with an estimated average
porosity of 20% and permeability of 100 mD. The
dimensions of all cores were kept constant for consistency with an average diameter of 3.8 cm and a length of
4.8 cm. The composite core stack was wrapped by a
layer of Teflon tape, one layer of aluminum foil and then
was capped with a layer of Teflon shrink tube. The
aluminum foil functioned as a diffusion barrier between
the core plugs and the overburden sleeve. The diffusion
of supercritical CO2 from the core plug into overburden is
minimized.
Fig. 2. Schematic of a PVT cell.
Coreflood apparatus and experimental procedure.
For this study, the coreflooding apparatus, RPS-855-Z,
from Coretest Systems Inc. (USA), was used for all
tests. Figure 3 shows a schematic illustration of the
apparatus. The components of this modifiable apparatus
include an oven, core holder, accumulators, injection
pumps, transducers, BPR, confining pressure control
system, gas totalizer and effluent collector. Injection
pressure, confining pressure, pore pressure, differential
Equipment and Procedures
PVT cell. Figure 2 shows a schematic of the DBR
system (model z16 ezs) with the PVT cell inside, 100 cc,
15 ksi, hydrogen sulfide (H2S) by Schlumberger. The
components of the PVT apparatus consists of an oven,
PVT cell, accumulators of water, recombined oil and
solvent, an injection pump, back pressure regulator
(BPR), mix cylinder, Anton-Paar DMA HPM density
meter, PVT data acquisition and tracking system
(camera).
Fig. 3. Coreflood schematic.
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pressure and flow rate were recorded automatically. The
production of oil and gas was measured at ambient
conditions. Three accumulators with auto-valves in the
oven were used for the injection of connate water,
seawater and crude oil, which were connected with a
Quizix pump. A CO2 cylinder with a pressure of 3,200 psi
and at room temperature was located outside the oven
and connected to another Quizix pump. Three Validyne
transducers in the system were used to measure the
differential pressure across the core plug during tests.
The core plugs for all ROZ coreflood experiments
were plugged from the reservoir sponge core and had
the OOIC paleo oil. No foreign fluids were introduced to
the core except CO2 to displace the OOIC. The
experimental procedure for these experiments is as
follows:
1. All core plugs are scanned by NMR to establish
baseline conditions.
2. Composite cores were wrapped by a layer of Teflon
tape, one layer of aluminum foil and then were
capped with a layer of Teflon shrink tube.
3. The composite cores with the paleo oil (ROZ) are
placed into a Hassler-type core holder at a confining
pressure of 1,300 psi and connect flow lines to a
core holder.
4. The Hassler-type core holder is oriented vertically to
achieve gravity stable injection with CO2.
5. The temperature of oven is set up to 102 °C and
allowed to stabilize overnight to reach temperature
equilibrium.
6. Pore and overburden pressures are increased in
500 psi steps using supercritical CO2 until 3,200 psi
pore pressure (test pressure) is achieved. The
bypass valve of the stack was opened during the
pore and overburden pressure set up process. The
injection is conducted at a flow rate of 1.0 cc/min
and the overburden pressure is maintained at 4,500
psi, which was achieved by confining the control
system.
7. After establishing the pore pressure of 3,200 psi, a
soak process between the supercritical CO2 and
ROZ paleo oil is established for 24 hours.
8. After the soaking period, CO2 injection begins at an
injection rate of 0.2 cc/min for all tests. The direction
of CO2 injection is from top to bottom of the stack
during the tests.
9. Gas production is measured by a gas totalizer and
oil production is collected by a fraction collector and
then quantitated at ambient conditions.
10. At the end of the CO2 injection core flooding
experiment, composite core plugs are depresssurized by decreasing pore pressure and
overburden pressure in 500 psi in steps to 1,300
psi overburden pressure.
11. Any oil production during the blow down process is
collected.
12. NMR scans on all cores follows the coreflood
experiments.
13. Dean Stark extraction is conducted to measure the
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14.
amounts of residual oil saturation after the
experiment.
Routine core analysis is conducted to measure the
core plug’s properties (permeability, porosity and
helium pore volume).
NMR. The NMR system used for the Carr-PurcellMeiboom-Gill (CPMG) measurements is an Oxford
Geospec 5 MHz NMR spectrometer and that used for
the spin echo single point imaging (SE-SPI) experi6, 7
ments is an Oxford DRX 8 MHz NMR spectrometer
with 3D water cooled 15 Gauss/cm electromagnetic
gradient coils for imaging. A custom built core holder
designed to locate the sample accurately at a repeatable
location within the magnet was used. The important
experimental parameters for the CPMG sequence with 5
MHz and SE-SPI sequence with 8 MHz, which are kept
identical throughout the current study, are:
[CPMG]
Recycling Delay: 15 sec
Echo Delay (Tau): 110 µsec
Total Number of Echo Trains (NECH): 45,456
Number of Scans: 16
[SE-SPI]
Recycling Delay: 10 sec
Echo Delay (Tau): 200 µsec
Total Number of Echo Trains (NECH): 512
Number of Scans: 8
Field of View: 5 cm
Encoding Time: 200 µsec
Gradient Stabilization Time: 400 µsec
Number of Echo Points (SI): 20
RESULTS AND DISCUSSION
PVT Cell (static experiments)
The purpose of this experiment is to visualize the ability
of CO2 to mobilize ROZ paleo oil. It was used as a
qualitative method to see if CO2 will be able to mobilize
dead paleo oil. Core plugs were specifically cut with a 1”
diameter and a 2” length to fit the PVT cell glass tube.
The core plugs were placed inside the PVT cell glass
tube (unaltered rocks) and CO2 was introduced to the
core plugs with gradual pressure increase, simultaneously with gradual increase in overburden pressure,
until a test pressure of 3,200 psi is reached. The DBR
system oven is heated overnight to stabilize the temperature. The core plugs is monitored throughout the
experiment by visually inspecting any changes on the
cores. Still images and videos are taken throughout the
experiment.
When the core plugs where left overnight soaking in
CO2, oil bubbles started to appear at the core plug
surface. The bubble’s sizes increased with time and
started to coalesce as the soaking period increased —
24 hours maximum soaking period. As the pressure is
Fig. 4. Still pictures of a PVT cell glass tube with core plugs.
The left image shows oil bubbles after CO2 soaking, and the
right image shows oil smearing the glass tube walls.
dropped to finalize the experiments, more oil starts to
come out of the core and smears the walls of the glass
tube, Fig. 4. These experiments proved visually the
ability of CO2 to mobilize paleo oil that wouldn’t be
produced by primary or secondary recovery means.
Coreflood (dynamic experiments)
Two types of coreflood experiments were conducted;
CO2 flooding ROZ dead paleo oil and CO2 flooding MPZ
dead oil. The latter was used as a proxy to ROZ paleo oil
and to compare the CO2 mobilization potential. MPZ
dead oil was flooded by CO2 after bringing the core to
connate water then flooded by seawater (secondary
recovery). Therefore, the MPZ is considered to be
introduced to reservoir cores. On the other hand, ROZ
paleo oil investigated in this study is the original paleo oil
in the core that was seen on logs, visual inspection of
the sponge core, and/or extraction from the same zone.
The difficulty in obtaining a live reservoir sample made
recreating paleo oil saturation in the laboratory very
difficult.
MPZ dead oil. In this experiment, MPZ deal oil was
collected from the separator and filtered using 5 microns
filter paper. The cores were saturated with the field
connate water then flushed with dead oil until irreducible
water saturation is reached. The dead oil is then waterflooded at reservoir conditions, 3,200 psi and 102 °C,
using seawater injection until residual oil after waterflood
is reached. This immediately was followed by CO2
injection at tertiary recovery mode to test the CO2
potential to mobilize residual oil. The mobilization of oil
for the two stages (secondary and tertiary) was typical of
a waterflood followed by CO2 injection. The mobilized oil
during CO2 injection (tertiary mode) was later compared
to that mobilized during CO2 injection into the ROZ.
ROZ paleo oil. In these experiments, preserved cores
plugged from the sponge core were used “as is” in all
CO2 flooding experiments, no fluids were introduced to
re-saturate the cores. The core plugs (1½” x 1½”) were
wrapped with a layer of Teflon tape; one layer of
aluminum foil and a layer of Teflon shrink tube before
they were stacked in two core composites inside the
core holder. The core holder is placed inside the oven;
the temperature is set at 102 °C and left overnight to
stabilize. CO2 is injected into the cores directly by
gradually increasing the injection pressure and overburden pressure simultaneously while maintaining at
least 1,000 psi differential pressure.
The ability of the CO2 to mobilize dead paleo oil
varied significantly based on the procedure of injection.
The first few experiments used continuous CO2 injection
into horizontally mounted cores that resulted in no
mobilization of dead paleo oil. This injection mode
resulted only in connate water production (mostly from
pressure blow down) with no oil production.
These results led to a modification of the experimental procedures to encourage the mobilization of
dead paleo oil in the cores. The extraction of hydrocarbons from core plugs in the same zone, well logs,
and NMR analysis all indicate oil saturations in the range
of 35% to 40%. This is similar to oil saturations after
waterflooding, indicating high potential of CO2 to
mobilize the oil. Therefore, it was decided to re-orient the
core holder vertically to take advantage of gravity stable
CO2 flooding and to improve the chances of mobilization.
Another modification to the experimental procedure was
the addition of a soaking period where CO2 was injected,
soaked for 24 hours, then the injection resumed. This
inject-soak-inject approach changed the outcome
significantly where most of the oil was displaced and
paleo oil was eventually mobilized. These results are
comparable to what was obtained from the MPZ dead oil
experiments. Figures 5 and 6 show the mobilized oil
from the ROZ after CO2 injection from Fields A and B,
respectively, using the inject-soak-inject approach.
Fig. 5. Mobilized dead paleo oil (ROZ) from Field A.
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Fig. 6. Mobilized dead paleo oil (ROZ) from Field B.
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meter before and after CO2 flooding. The core contains
oil and water only before CO2 flooding. The peaks with
T2 longer than 0.1 sec is mostly water. After CO2
flooding, the core only produced water, which can be
detected by the missing T2 peak longer than 0.1 sec,
Fig. 7a.
On the other hand, composite core sample 2A
mobilized oil and water. As can be seen from Fig. 7b,
most of fluids within the sample have been produced
after CO2 flooding.
To investigate the distribution of each fluid inside the
core samples before and after CO2 flooding and the
effectiveness of CO2 flooding throughout the whole
sample, a T2 distribution profile has been acquired by
the SE-SPI experiment, Fig. 8. The SE-SPI plot of
composite core sample 1A clearly shows the existence
of water and oil before CO2 flooding. Only water, T2
distribution longer than 0.1 sec, has been produced after
CO2 flooding for this sample as can be seen from Fig.
8b. Composite core sample 2A, however, proved almost
all fluids exist inside the core after CO2 flooding, Figs. 8c
and 8d. The SE-SPI data in Fig. 8 agrees well with the 5
MHz 1D CPMG data in Fig. 7. The displacement
efficiency of CO2 flooding is quite homogeneous
throughout the core with minor residual heavier oil
components saturation at the outlet of sample 2A.
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Figure 7 shows the core state before and after CO2
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(a) mobilize any oil,
core sample 1A from Field A that didn’t
measured by the 5 MHz Oxford Goespec NMR spectro-
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Fig. 7. T2 distribution of sample 1A (left) and sample 2A (right).
The blue solid line and the red dotted line are pre- and postCO2 flooding, respectively. Figure 7a shows no oil mobilization,
while Fig. 7b shows almost all fluids were mobilized after CO2
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SUMMER 2014
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Fig. 8. T2 distribution profile from SE-SPI measurement of sample 1A (a) and (b) and 2A (c) and (d). Figures 8a and 8c: pre-CO2
flooding, and Figs. 8b and 8d: post-CO2 flooding.
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Fig. 9. (a) The T2 distribution and (b) T2 distribution profile of sample 3B pre- and post-CO2 flooding. In Fig. 9a, the blue solid line and
the red dotted line are pre- and post-CO2 flooding, respectively. In Fig. 9b, the upper and the lower plot is pre- and post-CO2 flooding,
respectively. The guideline (red dotted line) in Fig. 9b is marking the two extreme points of T2 distribution before CO2 flooding.
Figure 9 also shows the 1D T2 distributions of
composite core sample 3B from Field B measured by the
5 MHz Goespec NMR spectrometer before and after
CO2 flooding. Unlike the composite core samples of
Field A, the composite cores in Field B only contain oil.
After CO2 flooding, only light and medium oil components have been produced and the heaviest oil compo-
nents were still left inside the core samples. The 8 MHz
SE-SPI data also shows the production of medium and
light oil components throughout the core homogeneously
after CO2 flooding, which are T2 distributions longer than
0.01 sec.
SAUDI ARAMCO JOURNAL OF TECHNOLOGY
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CONCLUSIONS
REFERENCES
This experimental study used core plugs from the ROZ
sponge core. The oil in these cores is dead oil, which
represents the worst case scenario. Better mobilization
by CO2 injection, or any other EOR method, should be
expected had this been applied on live reservoir oil
because of the availability of the lighter components in
the oil. This reservoir condition CO2 injection experiment still provided very important insights into the
potential of CO2 injection to mobilize paleo oil and the
following conclusions can be drawn:
1. Koperna, G.J., Melzer, L.S. and Kuuskraa, V.A.:
“Recovery of Oil Resources from the Residual and
Transitional Oil Zones of the Permian Basin,” SPE
paper 102972, presented at the SPE Annual
Technical Conference and Exhibition, San Antonio,
Texas, September 24-27, 2006.
1. The paleo oil resource in the ROZ can be significant;
however, it will not produce by primary and secondary recovery means, which shows the need to
study the trapping mechanism and recovery
potential.
2. Obtaining live reservoir samples from the ROZ is a
challenge. A live sample would provide more
accurate experimental data to understand the ROZ.
3. CO2 injection has the potential to mobilize paleo oil;
however, conventional CO2 injection into the ROZ
may not be as effective as it is in the MPZ, based on
the results of these experiments.
4. A soaking period is essential to mobilize the oil,
which will allow CO2 to interact with paleo oil and
mobilize it.
5. NMR results confirmed the potential to mobilize
paleo oil. More importantly, it showed which
components interacted with CO2 to mobilize the oil.
6. Medium and light components were the only
components mobilized by CO2 injection from these
experiments.
7. Further studies on the ROZ should focus on the
trapping mechanism. More specifically, attention
should be paid to pore size distribution and oil
characterization, which can provide more information
on the trapping mechanisms.
NOMENCLATURE
Kh
Kv
Sor
Swc
Horizontal Permeability
Vertical Permeability
Residual Oil Saturation
Connate Water Saturation
ACKNOWLEDGMENTS
The authors would like to thank the management of
Saudi Aramco and EXPEC Advanced Research Center
(EXPEC ARC) for the permission to publish this article.
Special thanks to Ziyad Alhellal for his help in the
extraction process.
SAUDI ARAMCO JOURNAL OF TECHNOLOGY
SUMMER 2014
2. Melzer, L.S., Kuuskraa, V.A. and Koperna, G.J.:
“The Origin and Resource Potential of Residual Oil
Zones,” SPE paper 102964, presented at the SPE
Annual Technical Conference and Exhibition, San
Antonio, Texas, September 24-27, 2006.
3. Skauge, A. and Surguchev, L.: “Gas Injection in
Paleo Oil Zones,” SPE paper 62996, presented at
the SPE Annual Technical Conference and
Exhibition, Dallas, Texas, October 1-4, 2000.
4. Kleinberg, R.L., Kenyon, W.E. and Mitra, P.P.:
“Mechanism of NMR Relaxation of Fluids in Rock,”
Journal of Magnetic Resonance, Series A, Vol. 108,
No. 2, June 1994, pp. 206-214.
5. Kleinberg, R.L. and Vinegar, H.J.: “NMR Properties
of Reservoir Fluids,” The Log Analyst, Vol. 37, No. 6,
1996, pp. 20-32.
6. Petrov, O.V., Ersland, G. and Balcom, B.J.: “T 2
Distribution Mapping Profiles with Phase-Encode
MRI,” Journal of Magnetic Resonance, Vol. 209, No.
1, March 2011, pp. 39-46.
7. Petrov, O.V. and Balcom, B.J.: “Two-Dimensional T2
Distribution Mapping in Porous Solids with Phase
Encode MRI,” Journal of Magnetic Resonance, Vol.
212, No. 1, September 2011, pp. 102-108.
BIOGRAPHIES
Dr. Ahmed A. Al-Eidan has worked in
several petroleum engineering
departments within Saudi Aramco,
including Production Engineering,
Offshore and Onshore Producing,
Reservoir Management, and the
Exploration and Petroleum Engineering
Center – Advance Research Center
(EXPEC ARC). Currently, he is a researcher in the
Reservoir Engineering Technology Division in EXPEC
ARC, responsible for increasing oil recovery by
innovative enhanced oil recovery (EOR) methods.
Ahmed is also the Upstream Coordinator for the
Corporate Carbon Management team.
He has been published several times and has
chaired and co-chaired several different technical
sessions and symposiums. Ahmed serves on the
scientific committee of King Abdulaziz City for Science
and Technology – Technical Innovation Center (KACSTTIC) for carbon capture and sequestration and is a
member of the Carbon Sequestration Leadership Forum
(CSLF) Technical Group and Project Interaction Review
Team (PIRT). He is an active member in the Society of
Petroleum Engineers (SPE), a Technical Editor for the
SPE Journal of Reservoir Engineering and Evaluation
(SPEREE), a Technical Editor for The Arabian Journal
for Science and Engineering, and is a member in the
International Honor Society for Petroleum Engineers (Pi
Epsilon Tau).
Ahmed is a certified petroleum engineer and
received his B.S. degree from Louisiana State
University, Baton Rouge, LA, his M.Eng. degree from the
University of Adelaide, Adelaide, South Australia, and
his Ph.D. degree from Texas A&M University, College
Station, TX, all in Petroleum Engineering.
Xianmin Zhou is currently a Petroleum
Engineer with 38 years of experience
working in Saudi Aramco’s Exploration
and Petroleum Engineering Center –
Advance Research Center (EXPEC
ARC). His focus areas are presently
paleo oil and heavy oil recovery
studies. Prior to joining Saudi Aramco
in 2010, Xianmin worked as a Senior Petroleum
Engineer/Senior Special Core Analyst for four major oil
companies: Daqing Petroleum Research Center, China;
and Core Lab Inc., Omni Labs Inc. and Intertek Westport
Technology Center, all located in the USA.
His areas of expertise include special core analysis,
CO2 and chemical enhanced oil recovery (EOR) studies,
reservoir characterization and developing method for
measuring two phase and three phase relative
permeability, coreflooding testing at reservoir conditions
and wettability studies.
Xianmin has authored or coauthored 22 papers on
the above subjects in Chinese and Canadian journals,
and several Society of Petroleum Engineers (SPE)
journals. He has published three patents.
In 1976, Xianmin received his B.S. degree in
Petroleum Engineering from Daqing Petroleum Institute,
Heilongjiang, China, and in 1996, Xianmin received his
M.S. degree in Chemical and Petroleum Engineering
from the University of Wyoming, Laramie, WY.
Dr. Hyung T. Kwak joined Saudi
Aramco in April 2010 as a Petroleum
Engineer with Saudi Aramco’s
Exploration and Petroleum Engineering
Center – Advance Research Center
(EXPEC ARC). He is currently a
member of Pore Scale Physics
program of the Reservoir Engineering
Technology Division. Hyung’s current research focus is
seeking deeper understanding of the fluid flow in the
reservoir rock pore system and pore structure itself
through modeling and experiments. Since joining Saudi
Aramco, he has been involved with various improved oil
recovery (IOR) and enhanced oil recovery (EOR)
research projects, such as SmartWater flooding, CO2
EOR, and chemical EOR. Prior to Hyung’s current
position, he was a research scientist at Baker Hughes,
and the main area of research was developing low field
NMR/MRI technology.
He received his B.S. degree in Chemistry from the
University Pittsburgh, Pittsburgh, PA, in 1996, and his
Ph.D. degree in Physical Chemistry from Ohio State
University, Columbus, Ohio, in 2001.
SAUDI ARAMCO JOURNAL OF TECHNOLOGY
SUMMER 2014
Dr. Sunil L. Kokal is a Senior
Petroleum Engineering Consultant and
a Focus Area Champion of enhanced oil
recovery (EOR) in the Reservoir
Engineering Technology team of Saudi
Aramco’s Exploration and Petroleum
Engineering Center – Advance
Research Center (EXPEC ARC). He
joined Saudi Aramco in April 1993. Since joining Saudi
Aramco, he has been involved in applied research
projects on EOR/improved oil recovery (IOR), reservoir
fluids, hydrocarbon phase behavior, heavy oil, and
production related challenges. Currently, Sunil is leading
a group of scientists, engineers and technicians to
develop a program for EOR and to conduct appropriate
studies and field EOR demonstration projects. The main
driver for his research is to increase the ultimate oil
recovery from 50% to 70% and add billions of barrels of
reserves.
Sunil has written over 100 technical papers and has
authored the chapters on “Crude Oil Emulsions” and
“Reservoir Fluid Sampling” for the revised edition of the
SPE Petroleum Engineering Handbook (2006). He is
currently the Associate Editor for the Journal of
Petroleum Science and Engineering. Sunil is also an
Associate Editor of the SPE Reservoir Evaluation and
Engineering Journal, and earlier served on the Editorial
Review Board of the Journal of Canadian Petroleum
Technology. He has been a keynote speaker, helped
organize several petroleum engineering related
conferences and symposia, and taught courses on EOR,
reservoir fluid properties and other related topics. Sunil
is a member of the Society of Petroleum Engineers
(SPE), and is a registered professional engineer and a
member of the Association of Professional Engineers,
Geologists and Geophysicists of Alberta (Canada).
He is the recipient of the prestigious 2012 SPE
DeGolyer Distinguished Service Medal, the 2011 SPE
Distinguished Service Award, the 2010 SPE Regional
Technical Award for Reservoir Description and
Dynamics, and the 2008 SPE Distinguished Member
Award for his services to the society. Sunil also served
as a SPE Distinguished Lecturer during 2007-2008. He
has received several other awards, including best paper
awards by the Canadian Petroleum Society, outstanding
Technical Editor award, and several interal company
awards for publications, service, teamwork, and
technical contributions. Sunil has mentored several
young professionals both at Saudi Aramco and for the
SPE.
In 1982, he received his B.S. degree in Chemical
Engineering from the Indian Institute of Technology, New
Delhi, India, and in 1987, Sunil received his Ph.D.
degree in Chemical Engineering from the University of
Calgary, Calgary, Alberta, Canada.
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