# Petroleum Production Operations Questions and Answers – Well Testing – Productivity or Deliverability Tests

This set of Petroleum Production Operations written test Questions & Answers focuses on “Well Testing – Productivity or Deliverability Tests”.

1. Productivity or Deliverability Tests can be applied to Non- Darcy, below the bubble point flow conditions.
a) True
b) False

Explanation: Yes, Productivity or Deliverability Tests can be applied to Non- Darcy, below the bubble point flow conditions. They can be applied to even though fluid properties and relative permeabilities are not constant.

2. What is the formula of the Productivity Index?
a) q/(Pi-Pwf)
b) (Pi-Pwf)/q
c) V/(Pi-Pwf)
d) q/(Pi.Pwf)

Explanation: The formula of the Productivity Index is flow rate/ (pressure drawdown). And pressure drawdown equals to the drop in pressure when the fluid comes from the formation to the well i.e. Average reservoir pressure – Bottom hole flowing pressure.

3. What is Absolute Open Flow Potential?
a) The production rate if the bottom hole flowing pressure can be reduced to zero
b) The production rate if the bottom hole shut-in pressure can be reduced to zero
c) The production rate if the bottom hole flowing pressure can be reduced to 1 atm
d) The production rate if the bottom hole shut-in pressure can be reduced to 1 atm

Explanation: Absolute Open Flow Potential is the production rate if the bottom hole flowing pressure can be reduced to zero or zero sand back pressure. Basically, we check the deliverability of the well when the bottom hole flowing pressure is zero but practically it is not possible to make the BHP zero.

4. Specific Productivity index is _____
a) q/(Pi-Pwf)
b) Productivity Index/Fluid density
c) (Pi-Pwf)/q
d) Productivity Index/Length of the producing zone

Explanation: Specific Productivity index is Productivity Index/Length of producing zone. Where the formula of Productivity Index is flow rate/ (pressure drawdown). And pressure drawdown equals to the drop in pressure when the fluid comes from the formation to the well i.e. Average reservoir pressure – Bottom hole flowing pressure.

5. If a well is producing above bubble point pressure then the Productivity Index will be constant for a wide range of drawdowns.
a) True
b) False

Explanation: This is true. If a well is producing above bubble point pressure then there is no gas coming out of the solution so the Productivity Index will be constant for a wide range of pressure draw-downs i.e. for a wide range of pressure drops in the wellbore.
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6. Which well is having the highest draw-down?

a) Well A
b) Well B
c) Well C
d) Well A and C

Explanation: Well c is having the highest drawdown. A range of drawdowns should be taken in order to better representation of the true Inflow Performance Relationships of the well. As the drawdown is increased it will come down to the lower region of the Pwf vs q curve here the drawdown is of the range of Well C > Well B > Well A.

7. Inflow after flow deliverability curve, which of the plot we generally use?
a) Pwf vs t
b) Pi vs t
c) (Pi2 – Pwf2) vs q
d) (Pi2 – Pwf2) vs t

Explanation: Inflow after flow deliverability curve we plot the curve between (Pi2 – Pwf2) vs q. i.e squared drawdown pressure vs flow rate. We plot this graph in a log-log paper. This gives a straight line and if we extend this line then we can predict the flow rate for any drawdown.

8. What is the full form of Mcfd?
a) Millions of standard cubic feet per day
b) Thousands of standard cubic feet per day
c) Hundreds of standard cubic feet per day
d) Standard cubic feet per day

Explanation: The full form of Mcfd is Thousands of standard cubic feet per day. It is a measure of the production of gas from the wells. A routine or periodic production tests are necessary in case of Well testing. Also the oil and gas company should take note of the production data of the amount of hydrocarbon been produced.

Sanfoundry Global Education & Learning Series – Petroleum Production Operations.