EOR of VN
EOR of VN
EOR of VN
(5.1)
5.1.4. Model Initialization
There are total of 2 reservoir simulation models have been
conducted by using a grid size of 100mX100mX50m for Southwest
and Northeast Su Tu Den parts with the OIIP are 448 and 152
million barrels respectively. However, their Oil Water Contacts and
reservoir pressures get same value at 4000mTVD and 305 atm (at
2800mTVD) respectively.
20
5.2. History matching
These model runs with production data up to the end of March
2011. The results of history matching indicate that actual pressures
from downhole gauges in almost all producers are very well mached
by the reservoir simulation models.
Based on all the information available from the field, it is felt that
the most likely explanation for the additional pressure support being
experienced by the basement reservoir is aquifers. Approximately 3.5
and 2.4 Billion stbw have been assumed to provide energy support
for the Southwest and Northeast areas respectively. The "Dual
porosity-single permeability" type model reflects the reservoir
behavior more exactly than other type model.
5.3. CO
2
flooding simulation and evaluation
5.3.1. Su Tu Den full field development plan
Currently there are 11 producers and 1 injector in Southwest, 8
producers in Northeast. The analysis results (table 5.5) indicate that
the water injection would been applied forward plan because of high
water cut in production wells.
Table 5.5. Recovery factors for Su Tu Den basement reservoir
Well count Current wells Furture wells
Area SW NE SW NE SW NE
Production 8 11 - - 1 -
Ultimate recovery (MMstb) 22.68 103.10 24.37 103.1
Recovery factor (%) 15 23 16 23
5.3.2. Miscible CO
2
flooding for EOR
From the results of laboratory study on the displacing oil by
flooding and the reservoir performance analysis, the concept model
of vertically continuous CO
2
flooding from top of basement (figure
5.13) is chosen for reservoir simulation.
21
Figure 5. 13. The concept model for vertical CO
2
flooding
Based on the reservoir simulation model, the cumulative gross
total CO
2
injected was then about 20 Million Sm
3
and had
contributed to 202 MMSTB oil, recovery factor of 33.34%.
CONCLUSIONS AND RECOMMENDATIONS
Conclusions
1. The application of enhanced oil recovery technology for Su Tu
Den basement reservoir is a necessary requirement when the current
oil production is decreasing daily .
2. The Su Tu Den fractured basement reservoir tend to have
complex structure of pore space, which involves two main
proportions: micro fracture providing the storage capacity, and
macro fracture providing the fluid-flow pathway from reservoir into
producers. The system like "dual porosity-single permeability"
3. The miscible CO
2
process is proposed as a suitable method for
application EOR in Su Tu Den basement reservoir. Once we injected
CO
2
into reservoir in miscible conditions, oil recovery will increased
by mechanisms: selling oil, increasing oil saturation in fractured
media, increasing the effected permeability to oil, reduction of oil
viscosity and density.
22
4. The results of laboratory study indicated that the oil recovery
factor was low and depended on the rate of water injection. The
concept model of vertically CO
2
flooding from top of basement,
shows the high oil displacement. The oil displacing performance
indicates that oil is displaced from micro fracture by oil swelling and
interfacial tension reduction; oil bank is developed, and flow down
by gravity force effect.
5. The results of computer simulation and screening indicated the
high oil incremental recovery factor of 12.5% OIP, when applying
the continuous CO2-EOR method for full field of the STD basement
reservoir based on current well pattern.
Recommendations
- Continue to study and estimate the application for CO
2
flooding
with economic evaluation. Evaluate exactly the current
production performance of Su Tu Den basement reservoir.
- Conduct field measurement of residual oil saturation after the
primary and secondary production. Su Tu Den basement
reservoir has low recovery factor, thus we should conduct EOR
techniques have the potential of recovering significant
incremental oil volumes.
- Design small pilot test in SD-D areas of Su Tu Den basement
reservoir. Based on the results of pilot test, the concept model of
miscible CO2 flooding should be enhanced.
- Investigate the CO
2
sources, focus on: (i) flue gas from plants
such as power plant gas, natural gas processing...; and (ii) the
neighbor feilds have high CO
2
content. Conduct the economic
model to evaluate response scenarios for specific plan.
23
LIST OF PUBLISHED WORKS OF AUTHORS
1. Le Xuan Lan, Nguyen Hai An (2007), Enhance oil recovery
by cacbone dioxide flooding. Proceeding of the International
symposium Hanoi Geoengineering.
2. Nguyn Hi An et. al (2008), Nghin cu ng dng m hnh
thy nhit ng lc cho i tng mng nt n m Bch H,
Petrovietnam Journal, Vol 4, pp 33-36.
3. Nguyn Hi An et. al (2008), Nghin cu nh gi v xut
cng ngh khai thc du trong mng m S T en, ti
NCKH cp ngnh.
4. Kawahara. Y, Nguyen Hai An, et. al (2009), Comprehensive
CO
2
EOR study Study on Applicability of CO
2
EOR to block
15-2, Offshore Vietnam, Rang Dong Field part I Laboratory
Study, Petrovietnam Journal, Vol 6, pp 44-51.
5. Nguyn Hi An, L Xun Ln (2009), Kho st c ch trn ln
CO
2
vi du th tng mng nt n m S T en trong iu
kin va, ti NCKH cp trng.
6. Nguyn Hi An, L Xun Ln (2010), ng dng phng trnh
trng thi (EOS) trong m hnh ha c tnh du va mng S
T en v d bo p sut trn ln nh nht khi bm p CO
2
,
Tuyn tp bo co hi ngh khoa hc v cng ngh quc t,
Tp on Du kh Quc gia Vit Nam.
7. Nguyn Hu Trung, Nguyn Hi An v nnk (2010), Bm p
CO
2
gia tng thu hi du kh cho b Cu Long, Tuyn tp bo
co hi ngh khoa hc v cng ngh quc t, Tp on Du kh
Quc gia Vit Nam.
24
8. Nguyen Hai An and Le Xuan Lan (2010), Combination of
underground CO
2
storage and increased oil recovery in
SuTuDen-SW fractured basement reservoir. Proceeding of the
International symposium Hanoi Geoengineering.
9. Nguyn Hi An, L Xun Ln (2010), M phng khai thc du
bng phng php bm p CO
2
trn ln, p dng cho khi SD-
D i tng mng nt n m S T en, ti NCKH cp
trng.
10. Nguyn Hi An, L Xun Ln v nnk (2011), Kt hp chn vi
CO
2
cng vi vic nng cao h s thu hi du ti tng mng nt
n Ty Nam-S T en, Tp ch KHKT M-a cht, S 34,
Trang 3-8.
11. Nguyn Hi An, Nguyn Hong c v nnk (2011), ng
dng ca cng ngh Nano trong cng nghip Du kh, Tp ch
KHKT M-a cht, S 34, Trang 60-65.