The document discusses a pressure drawdown test, which involves measuring bottom hole pressure during a constant production flow after a well's shutdown. Its objectives include assessing average permeability, skin factor, and reservoir homogeneities within the drainage area. The test has advantages such as no cash flow loss during testing and applicable for new or long-closed wells, but also has disadvantages like difficulty in maintaining a constant flow rate and not determining average reservoir pressure.

1. Name: Hishmat Rai
Roll no: 16PG46
Topic :Demostration on
Pressure Drawdown Test
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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
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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
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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
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7. Equation use in this test to measure parameter
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• 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
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