The objective of this project was to identify various methods for well test in horizontal wells. Well test analysis in horizontal wells is applied to find the reservoir parameters like permeability and skin factor and the result from the chosen methods will be compared to the result of some famous software like Kappa Saphir, PanSystem, etc which are used in oil and gas industries.

1. BTP-03
Well test analysis in
horizontal well
1

2. Aim of the project
• To analyze the well test data in horizontal
wells
• Mainly by the means of using different
software used in industries
• Predicting reservoir parameters like
permeability, wellbore storage, skin factor
and also about anisotropy
2

3. Problems in Horizontal Well
Testing
• Three dimensional flow geometry -
Interpretation
• Zonal variation of vertical permeability
• The general flow patterns that are
encountered in horizontal well testing:
– Early linear and radial
– Late linear and radial
3

4. Problem Statement
•
4

5. •
5

6. Production schedule
First Shut-in 5.47 hours Stimulating well
period
First pumping 5minutes Using
period submersible
pump
Second shut-in 9.25 hours Take out plug at
period 1963(MD) and
BHP gauge to
2182(MD)
Second pumping 8.08 hours Using
period submersible
pump
Final shut-in 12.08 hours Build up test
period
6

7. •
7

8. Pressure buildup data
T (min) P (psi)
0 808.49
5 4.95 810.98
10 14.55 815.23
20 19.21 817.25
30 28.25 820.66
40 36.95 823.6
50 45.33 826.17
60 53.39 828.42
80 68.67 832.2
100 82.91 835.25
120 96.2 827.75
140 108.64 839.85
8

9. T (min) P (psi)
160 120.31 841.63
180 131.28 843.16
200 141.61 844.49
240 160.55 846.69
280 177.52 848.43
320 192.8 849.85
360 206.63 851.02
420 222.76 852.58
480 241.24 853.58
540 255.21 854.5
600 269.2 855.26
660 279.56 855.91
725 290.6 856.5
9

10. The problem was solved using
two software:
• Kappa Saphir
• Pansystem
Solution by Kappa Saphir
10

11. History Curve
• The pressure dots suggests data was here
• This led• tocontinous line shut-in points given
While theThe before the highlighted not
initial pressure of 868.156 psia
which was calculated result generateditself
shows the calculated by the software by
based on the improvement parameters
software
selected 11

12. Derivative Plot
12

13. Derivative Plot - 2
The main characteristics:
• Slant straight red line showing wellbore effects
• Zero slope dotted line showing either early radial or
late radial flow 13

14. Horner Plot
• This plot was essential to determine the end of
wellbore effect.
14

15. Early Radial or Late Radial
• Help of Horner plot (both in Kappa and
PanSystem) and following correlation:
• To end the early time radial flow,
1800d z2 ct 1800  22.52  0.33  31 105
te  
kv 232.1
 0.40 hours
• But the Horner plot shows that by the time
zero slope line starts, this early radial is
already eliminated
15

16. Result of Kappa Saphir
We calculated the skin and permeability
from Kappa Saphir and estimations are as
follows :
Skin= -6.04
Permeability= 7780 mD
Cs = 6.76 bbl/psi
16

17. Solution by Pan System
17

18. History Curve
Assumed Model:
Two No Flow Boundary – Homogenous
Infinite Acting Reservoir
18

19. Derivative Plot
Line With One Slope: Line With Zero Slope:
• Wellbore Stroge Flow period • Pseudo Radial Flow
• This gives Wellbore Storage • This gives value of permeability k and
Coefficient Pseudo radial Skin factor
19

20. Derivative Plot with
Extrapolation
Simulated Derivative Plot:
Parameter:
Cs= 4.0287 bbl/psi
k= 8069.11 mD
Kz= 8069.11 mD
Cd= 345372.7551
kh= 363110.1493 mD-ft
Zwd= 0.5
Lw= 1531 ft
20

21. Horner Plot
Extrapolation of radial flow line gives initial pressure Pi=864.11 psi
21

22. Result of PanSystem
The estimated value of skin and
permeability of the same problem
statement are as follows :
• Skin = -5.965
• Permeability = 8026.6 mD
• Cs = 4.0287 bbl/psi
22

23. Anisotropy
• It means different properties in different
directions.
• Anisotropy can be indicated by the ratio
of horizontal to vertical well’s productivity
index.
• Hence, it is indicated by Jh/Jv.
Where Jh is horizontal productivity index.
Jv is vertical productivity index.
23

24. Giger, Reiss and Jourdan
Jh ln( rev / rw )

Jv 1  1  ( L / 2r )2   h   h 
ln  eh
    ln  


L / 2reh   L   2 rw 

reh  1667.4 ft and rev  1179.03 ft
Jh
  6.3769
Jv
24

25. Giger
qh 0.007078kh L
Jh  
P  1  1  L / 2 r 2 
 eh 
o Bo  ln    C
L
h  L / 2reh 

  

Where,
 h 
C  ln  
 2 rw 
qv 0.007078kh
Jv  
P  rev 
 B ln  
 rw 
J h 26.9867
   5.926
J v 5.04802
25

26. Borisov Method
qh 0.007078kh /  B
Jh  
P  4reh  h  h 
ln 
 L    L ln  2 r 
 w
Hence,
J h 26.9867

J v 5.04802
 5.346
26

27. Comparison of the anisotropy
Giger et all Giger Borisov
Jh/Jv 6.3769 5.926 5.346
• Thus, the results from all the three methods are almost same with
an average of 5.88 which clearly indicates that the productivity in
case of horizontal wells is higher and also the well is possibly having
more vertical permeability.
27

28. Problem-2
28

29. Problem-2
29

30. Derivative Plot (simulated)
30

31. 1) Wellbore Storage Line:
• Slope 1
• Gives Wellbore Storage Coefficient
2) Early Radial Flow Line:
• Slope Zero
• Gives Skin, kbar(kbar=(k*kz)^(1/2), Skin
3) Linear Flow Through Layer:
• Slope Half
• Gives Effective Producing Length of Well
4) Late Radial Flow:
• Slope Zero
• Gives Vertical Permeability(k), Horizontal Permeability(kz), Pseudo Radial
Skin factor
31

32. Simulated Radial Plot
32

33. Comparison between
Kappa and PanSystem
and
Conlusion
33

34. Kappa PanSystem Abs. %age Abs. %age
error with error with
base Kappa base
Pansystem
kh total 3.5*105 md.ft 3.61*105 3.142% 3.047%
md.ft
k average 7780 md 8026.61 3.169% 3.072%
Skin -6.04 -5.965 1.241% 1.257%
34

35. Conclusion
• The difference in result of both Kappa
and PanSystem is never more than 3.5%.
Hence both results can be considered
reliable.
• However for industrial purpose Kappa is
more popular due to its faster processing
speed.
35

36. Conclusion
• When the results are compared we find
that both software provide almost similar
output. The difference in the result occurs
due to use of different numerical
methods by both Kappa and PanSystem.
• The numerical method used by both
Kappa and PanSystem is not disclosed
hence which software is more accurate
cannot be predicted.
36

37. References
1. A.M.Al-Otaibi, SPE, Technological College of Studies, E.ozkan, SPE, Colorado school of
mines, “Interpretation of Skin Effect from Pressure Transient Tests in Horizontal Wells”,
paper SPE 93296, presented at 14th SPE Middle East Oil & Gas Show and Conference held
in Bahrain International Exhibition, Bahrain, 12-15 March 2005.
2. Amanat U. Chaudhary: Gas Well Testing Handbook, Advanced TWPSOM Petroleum
Systems, Inc., Houston, Texas, USA, 2003.
3. Amanat U. Chaudhary: Oil well testing Handbook, Advanced TWPSOM Petroleum Systems,
Inc., Houston, Texas, USA, 2004.
4. Aziz S. Odeh and D. K. Basu: “Transient Flow behaviors of horizontal wells: Pressure
drawdown and Buildup analysis”, Mobil R&D Corp. SPE formation evaluation, March 1990
presented at.
5. Commercial Well-Testing Software “Saphir”, http://www.kappaeng.com/, KAPPA
Engineering, France 1987-2003
6. Dominique Bourdet, Well Test Analysis: The use of advanced interpretation models,
Handbook of Petroleum Exploration and Production,3
7. L. Mattar, M. Santo: “A practical and systematic approach to horizontal well test analysis”,
The Journal of Canadian Petroleum Technology,34(9), November 1995.
8. S.D.Joshi: Horizontal Well Technology, Joshi Technologies International, Inc., Tulsa, OK,
USA, 1991.
9. Wang H.: “Analysis of Horizontal Oil Well Performance,” MS.Thesis, U. of Oklahoma,
Norman,OK,1996.
10. Well test interpretation, Schlumberger, 2002. 37

38. Thank you
38