Pressure draw test 1 procedure and objective 2 advantage and disadvantage 3 equation use to determine parameters

1. Name: Hishmat Rai
Roll no: 16PG46
Topic :Demostration on
Pressure Drawdown Test
1

2. Presure Drawdown test
• The measurement and analysis of pressure
data taken after a well is put on production ,
either initially or after shut in period.
• A pressure drawdown test is simply series of
of bottom hole pressure measurements made
during a period of flow at constant production
rate
2

3. Objective of pressure Drawdown test
• Average permeability within drainage arera of
the well
• Skin fector(damage or Improve)
• It determine the pore volume
• Rerservoir homogeneities within drainage
area of the reservoir
3

4. Procedure of Pressure Drawdown test
• Step1: Shut the well for the period of time to
equalize the pressure throughout the reservoir
• step 2: Pressure equimpent (Electronic Guage
) is lowerd into the well to measure pressure
from bottom to top of well
• Step 3: when flow begun at constant rate and
the bottom hole pressure measured
continuesly 4

5. Advantage of Draw Down Test
• No loss of cash flow due to shut in of the well
during test time , It means producing while
testing
• It determines the boundries of the reservoir.
• It is particularly applicable for new well or
wells that have been closed for long time
5

6. Disadvantage of Drawdown test
• It is difficult to flow the well at constant rate .
• It doesnt determine the average reservoir
pressure.
• In order to get accurate analysis of drawdon,
its critical that no choke change during the
test.
• Pressure drawn down test is noisy test
6

7. Equation use in this test to measure parameter
7
• pwf =Pi+162.6qBµ/kh[log(1,688صctr2
w /kt)-0.869s]
k=162.6qBµ/mh,
m=162.6qBµ/kh
• S=1.151[ { (pi-pwf)/m} - log { k/ q µ ct r2 w }+3.23]
ct=co So +cw Sw +cgSg +cr
m is calculate from semilog graph.
Noi=Ø(av)So (av) VB / Bo(av)
Vp =ØVB
t
2
inv
c
kt
10434.2r




8. Conclusion
• We conduct the test for measurement with
out production loss.
• Form pressure drawdown test, we determine
the average permeablity , skin factor ,pore
voume
8