1. ETAP
June 29th ,2015
President
Mr.Jamel Abdennaceur
Ouali
PETROFAC Tutor
Mr. Abdellatif TLILI
Academic tutor
Mr.Riadh Ahmadi
Reviewer
Mr.Monji Felhi
NATIONAL ENGINEERING SCHOOL OF SFAX
Dissertation
To Obtain
National Engineer Diploma in Geology
CHERGUI RESERVOIR STUDY AND MASS
BALANCE DETERMINATION USING SOFTWARES
AND SPREAD-SHEETS
Presented By:
Ines MASMOUDI
Figure 1

2. ETAP
PLAN
• Project Context
• Chergui Field Localization
• Geological Overview
• Wells Modeling using Prosper Software
• Reservoir Modeling using Mbal Software and Spread-sheets
• Total System Modeling using Gap Software
• Conclusion and Perspectives
Figure 2

3. ETAP
Project Context
Figure 3

4. ETAP
Project Context
Our study consists in establishing a global system modeling starting
from the reservoir till separators in order to interpret reservoir simulation
and forecast production in term of system potential and optimum rate.
GAP
• Reservoir Modeling
• Mass Balance Method
• Wells Modeling
• Gas Rate Estimation
Total System Production ForecastFigure 4

5. ETAP
Chergui Field Localization
Figure 5

6. ETAPETAP
Chergui Field Localization
High Arch
Kerkennah Islands
Sfax city
Seaway
Chergui
concession
CPF
petro
fac
Figure 6

7. ETAP
Geological Overview
Figure 7

8. ETAP
Geological Overview
Petroleum System
Source Rock Seal Rock
Reservoir Rock
• Bahloul Member (Cenomanian, Turonian; Late Crateceous)
• Boudabbous Fm. (Yprisian Lutetian; Eocene)
Both of them are suspected to be source rock for our reservoir.
because they have already reached the maturity interval.
• Souar Fm. (Late Eocene),
• Average Thikness : 800m,
• Mainly formed by Claystone,
• Limestone Member divided this formation on Upper claystone and lower
claystone
• Reineche Member
• Average thikness : 10m
• Formed by Nummilitic Limestone
Figure 8

9. ETAP
Geological Overview
Major NW-SE Fault; Separating
Tank32 andTank38
Tank 32
Tank 38
CRG-8
CRG-1
CRG-3
CRG-6
CRG-5
CRG-4
CRG-2
Tank 32 :
• CRG-1
•CRG-3
•CRG-8
Tank 38 :
•CRG-5
•CRG-6
Seismic top Reineche
Depth Map
Figure 9

10. ETAP
Wells Modeling using PROSPER
Software Figure 10

11. ETAP
Wells modeling using Prosper Software
Prosper Work Flow
1. Model Construction
2. Well Test Analysis
3. Estimation of the Gas
Flow Rate
Defining the Well type and the
reservoir fluid
Defining the PVT Data
Defining the Equipment Data
Generate IPR Curve
Generate VLP Curve
Figure 11

12. ETAP
CRG-1A Work Flow
Wells modeling using Prosper Software
1. Model Construction
Defining the Well type and the
reservoir fluid
Defining the PVT Data
Defining the Equipment Data
Generate IPR Curve
Generate VLP Curve
Figure 12

13. ETAP
Wells modeling using Prosper Software
2. Well Test Analysis
CRG-1A Work Flow
1. Model Construction
Figure 13

14. ETAP
3. Estimation of the Gas Flow Rate
CRG-1A Work Flow
Wells modeling using Prosper Software
2. Well Test Analysis
9.2
CRG-1A Deliverability Curve
1. Model Construction
Figure 14

15. ETAP
CRG-1A
Reservoir Pressure : 92 Barg
Reservoir Permeability : 35.2 mD
Skin Factor : 0
Wells modeling using Prosper Software
Well
Deliverability
Curves
9.19
CRG-3
Reservoir Pressure : 99 Barg
Reservoir Permeability : 6 mD
Skin Factor : 0.5
1.94
CRG-5
Reservoir Pressure : 106 Barg
Reservoir Permeability : 20 mD
Skin Factor : 1.5
10.05
CRG-6
Reservoir Pressure : 105 Barg
Reservoir Permeability : 6 mD
Skin Factor : 1.5
2.46
CRG-8
Reservoir Pressure : 99 Barg
Reservoir Permeability : 40 mD
Skin Factor : -1
11.2
Figure 15

16. ETAP
Wells modeling using Prosper Software
Figure 16

17. ETAP
Reservoir Modeling using Mbal
Software and two Spread-SheetsFigure 17

18. ETAP
Reservoir Modeling using MBAL Software
and Spread-Sheets
MBAL Work Flow
1. Model Construction
2. Production History Simulation
3. Production Forecast
Defining the system summary of
Tanks
Defining the PVT Data
Defining Tanks Parameters
Figure 18

19. ETAP
Tank 32 MBAL Work Flow
1. Model Construction
Reservoir Modeling using MBAL Software
and Spread-Sheets
Figure 19

20. ETAP
Tank 32 MBAL Work Flow
1. Model Construction
2. Production History Simulation
3. Production forecast
Reservoir Modeling using MBAL Software
and Spread-Sheets
Figure 20

21. ETAP
Tanks results
TANK 32
Date Prediction Curve
725 Psig ; 06/10/2017
Cumulative Gas Prediction Production Curve
725 Psig ; 1.8 BSm3
Reservoir Modeling using MBAL Software
and Spread-Sheets
Figure 21

22. ETAP
MBAL Outputs
TANK 38
Date Prediction Curve
725 Psig ; 20/05/2023
Cumulative Gas Prediction Production Curve
725 Psig ; 1.05 BSm3
Reservoir Modeling using MBAL Software
and Spread-Sheets
Figure 22

23. ETAP
First Spread-Sheet Outputs
TANK 32
Reservoir Modeling using MBAL Software
and Spread-Sheets
Figure 23

24. ETAP
First Spread-Sheet Outputs
TANK 38
Reservoir Modeling using MBAL Software
and Spread-Sheets
Figure 24

25. ETAP
TANK 32
Second Spread-Sheet Outputs
Gas Recovery factor (%) 69,4
Recoverable reserves (Bm3) 1.51
Original gas in place (Bm3) 2.18
Reservoir volume (AC.FT.) 112 920
Reservoir Modeling using MBAL Software
and Spread-Sheets
Figure 25

26. ETAP
TANK 38
Second Spread-Sheet Outputs
Gas Recovery factor (%) 70.6
Recoverable reserves (Bm3) 1.48
Original gas in place (Bm3) 2.11
Reservoir volume (AC.FT.) 107 453
Reservoir Modeling using MBAL Software
and Spread-Sheets
Figure 26

27. ETAP
Comparison Between MBAL Software Results and Two Spread-Sheets
TANK 32
Reservoir Modeling using MBAL Software
and Spread-Sheets
Figure 27
MBAL results First spread sheet
results
Second spread sheet
results
Initial Gas In Place (BSm3) 2.62 2.87 2.18
Recovery Factor 68.7% 65.85% 69.4%
Current Cumulative Gas produced
(BSm3)
1.15 1.15 1.07
Remaining Gas Reserves (BSm3) 1.47 1.77 1.11
Total Cumulative Gas In the end date
of natural production (BSm3)
1.80 1.89 1.51
Depletion Date 21/12/2020 19/07/2024 None
Date of Natural Production End
(725 Psig)
06/10/2017 24/06/2019 None
MBAL results First spread sheet
results
Second spread
sheet results
Initial Gas In Place (BNm3) 1.49 1.9 2.23
Recovery Factor 70% 67% 70,6%
Current Cumulative Gas produced
(BNm3)
0.65 0.65 0.79
Remaining Gas Reserves (BNm3) 0.89 1.24 1.44
Total Cumulative Gas In the end date of
natural production (BNm3)
1.05 1.28 1.56
Depletion Date 08/05/2032 19/07/2024 None
Date of Natural Production End
(725 Psig)
20/05/2023 24/06/2019 None
 MBAL is a reliable model so we are going to use its
outputs in the next part.
TANK 38

28. ETAP
Although, MBAL gives us a constant gas rate 24 MMscf/d for Tank 32
and 4.6 MMscf/d for Tank 38 based on initial gas reserves
Reservoir Modeling using MBAL Software
and Spread-Sheets
Figure 28

29. ETAP
Total System Modeling using
GAP Software Figure 29

30. ETAP
Total System Modeling using GAP Software
GAP Work Flow
1. Build the GAP Network
2. Run Prediction
Draw the GAP Network
Define the Reservoir
Define the Wells
Define the Surface Equipments
Figure 30

31. ETAP
GAP Work Flow
1. Build the GAP Network
Draw the GAP Network
Total System Modeling using GAP Software
Figure 31

32. ETAP
GAP Work Flow
1. Build the GAP Network
Total System Modeling using GAP Software
Figure 32

33. ETAP
GAP Work Flow
2. Run Prediction
1. Build the GAP Network
Total System Modeling using GAP Software
Figure 33

34. ETAP
GAP Outputs
Total System Prediction Production
CHR-3 re-opening
CHR-6 re-opening
Total System Modeling using GAP Software
Figure 34
14.188
28.383

35. ETAP
GAP Outputs
Wells Results
0
2
4
6
8
CRG-1A CRG-3 CRG-5 CRG-6 CRG8
6.302
0.634
3.646
0.593
5.453
GasRate(MMscf/d)
Gas wells contribution
Total System Modeling using GAP Software
Figure 35

36. ETAP
Conclusion and Perspective
Figure 36

37. ETAP
According to PROSPER, MBAL and GAP Softwares the final results indicates that
the agreement condition between Petrofac and STEG about the minimum Gas
flow rate (16.42 MMscf/d) will be reached at 28/09/2016.
Conclusion and Perspective
2015 2016 2017
2015 2016 2017
Petrofac should find a quick solution to respect its engagement after the deadline
of 2016. We suggest drilling new wells as far as possible, if it is not possible due
to unrest and strikes, the urgent solution to satisfy the contract with STEG is to
install a Turbo Compressor in the inlet Manifold by the end of 2015.
Figure 37

38. ETAP
Thank You For Your
Attention My Parents
Mr. Abdellatif Tlili
Mr. Riadh Ahmadi
My Sisters : Yossra & Imen
My Husband
My Friends
Figure 38