5. EXAMPLE : GIVEN DATA ARE ,FLOW RATE =500 BBL /DAY,
TUBING SIZE =1.5 INCH, THE PRODUCTION ALL OIL, GLR=200
SCF/BBL, WELL DEPTH 5000 FT, PTH =200 PSI.
CALCULATE PWF FROM THE ABOVE GIVEN DATA.
SOLUTION :
1- CHOOSE THE WORKING CHART FOR QO=500 BBL/DAY AND
TUBING SIZE =1.5 INCH.
2- INTER THE CHART WITH THE VALUE OF PTH=200 PSI FROM X-
AXIS.
3- USE THE GLR =200 SCF/BBL CURVE TO FIND THE EQUIVELENT
DEPTH FOR PTH ON Y-AXIS.
4- THE EQUIVELENT DEPTH FOR PTH= 1300 FT.
5- FIND THE EQUIVELENT DEPTH FOR
PWF=EQUVELENT DEPTH FOR PTH+WELL DEPTH
= 1300+5000=6300FT.
6-USE THE SAME GLR =200 SCF/BBL TO FIND THE VALUE OF
PWF= 1600 PSI
PTH PWF
6. Vertical Working Charts : are defined as graphical presentation of multi phase correlation
( vertical and horizontal flow), that were constructed as relationship between pressure
and depth for different flow rates, pipes size, GLR gas liquid ratio
Pressure
depth
Flow rate
Pipe size
GLR
7. We have vertical and horizontal working chart , these chart build depend on oil API gravity
and gas specific gravity and average flowing temperature, through these charts , we can
constructing vertical flow performance with IPR.
The cross point between IPR and vertical flow performance (VFP) represent the allowable
flow rate.
Cross point
8. Example depth =6000 ft, tubing size=2 inch, Pr=3000 psi, GLR=400 scf/bbl, Pth=200 Psi,
(well head pressure), Qo=400 bbl/day ( all oil).
Determine Pwf from working chart.
Solution:
Pth= 120 psi
Equivalent depth to Pth= 2200 psi .
Equivalent depth to pwf= 2200+6000=8200 ft
Pwf =1230 Psi
Now find Pth from Pwf=1230 psi
Solution :
Equivalent depth to Pwf= 8200 ft
Equivalent depth to Pth= 8200-6000 = 2200 ft
So Pth from working charts = 120 Psi
12. Tubing in fig(1) greater than tubing in fig(2)
Heriot Watt
Fig 1 Fig 2 Fig 3
13. Example
Pr=2000 Psi, PI= 1.5 bbl/day/psi, qo=400 bbl/day, all oil, depth =6000 ft, GLR=400 scf/bbl, Pth=200 Psi tubing
size=2 inch.
Solution :
Find Pwf from Pr=2000 psi, qo=400 bbl/day, PI=1.5 bbl/day/psi
๐๐ผ =
๐๐
๐๐ โ ๐๐ค๐
= 1.5 =
400
2000 โ ๐๐ค๐
=== ๐๐ค๐ = 1733 ๐๐ ๐
Now IPR can be constructed from Pr and (pwf, qo),( two test points)
To construct the vertical flow performance need to assume qo ( available from working charts ) to find pwf
depending on Pth, as follows :
From working charts for tubing size 2 inches we have different flow rate ( 200, 400, 600, 800, 1000, 1500), from
these charts find Pwf for each flow rate:
Flow rate (
available )
Pwf (from working charts for Pth =120 psi)
200 1100
400 1300
600 1380
800 1450
1000 1570
1500 1800
Pwf
qo
2000
0
1733
400
1000
1500