d

1. Well Deliverability

2. Outline
• Vertical lift performance (VLP)
• Graphic solution for the operating point
(Nodal analysis)

3. Vertical Lift Performance (VLP)
• Wellhead pressure and wellbore flow
control the backpressure against the
reservoir
• VLP determines the backpressure
• This backpressure determines well
deliverability

5. Construction of VLP Curve
• For a given wellhead pressure (phf), assume a
series of production rate values (q) and estimate
bottom hole pressure values (pwf) with
– gradient curves, or
– wellbore flow performance models, or
– computer programs
• Plot pwf versus production rate q.

8. Example 1
Tubing size: 3.5 in.
Depth: 8,000 ft
GOR 2.0 Mscf/bbl
Wellhead pressure: 400 psia
Construct VLP curve

12. Solution
Production Rate, q Bottom Hole Pressure, pwf
STB/d psia
200 1240
400 1270
600 1300

13. VLP Curve Example
1000
1050
1100
1150
1200
1250
1300
1350
1400
1450
1500
0 100 200 300 400 500 600 700
q (STB/d)
p
wf
(psia)

14. Operating Point Determination
(Nodal Analysis)
• Plot IPR curve
• Plo VLP curve
• Find the intersection point

16. Example 2
Undersaturated oil reservoir
Reservoir pressure: 1,500 psia
Productivity index: 1.4 STB/d-psi
VLP: Example 1

17. Graphical Solution for the Operating Point
1000
1050
1100
1150
1200
1250
1300
1350
1400
1450
1500
0 100 200 300 400 500 600 700
q (STB/d)
p
wf
(psia)
q = 330 STB/d
pw f = 1270 psia
Operating Point
VLP
IPR

18. Example 8-1:
Single phase flow.

19. Example 8-3:
Effect of wellhead
pressure.

20. Example 8-4:
Effect of skin
factor.

21. Example 8-4:
Effect of reservoir
pressure.

22. Example 8-5:
Two-phase flow.