Well Control: Principles and Procedures - Static and Dynamic Pressures

1. Which one of the following will affect Bottom-hole pressure (BHP) while circulating at a constant flow rate (TWO ANSWERS)

a- Mud density
b- Annulus pressure loss
c- Pump pressure
d- Pressure loss through the drilling bit nozzles

2. The equivalent circulating density (ECD) determines the actual bottom hole pressure while circulating. Which part of the system pressure losses contributes to the ECD?

a- The pressure loss in the surface system
b- The pressure loss over the nozzles
c- The pressure loss in the drill string
d- The pressure loss in the annulus
e- The pressure loss in the open hole section only

3. The Driller pumps a heavy slug and displaces it to the drill pipe with active pit fluid. What effect will this have on the fluid pits after disconnecting the top drive?

a- Decrease in volume
b- Increase in volume
c- No change in volume

4. During normal drilling operations, 20 bbl of light fluid is pumped into the string followed by original mud. With the light fluid inside the drill pipe, the Driller shuts down the pumps to monitor the well. What happens to the Bottom Hole Pressure (BHP)?

a- The BHP pressure will increase, and the back pressure will show on the drill pipe pressure gauge.
b- The BHP pressure will remain the same, but a back pressure will show on the drill pipe pressure gauge
c- The BHP will decrease, and there will be no back pressure showing on the drill pipe pressure gauge.

5. Which factors will affect Bottom Hole Pressure (BHP) while circulating at a constant flow rate? Choose two answers

a- Annulus pressure losses
b- Drill string pressure loss.
c- Drilling fluid density
d- Pressure losses through the drilling bit nozzles
e- Pump pressure

6. The pit level increases when the pumps are off, but the pit level stays constant when the pumps are running. What could be the problem?

a- The hydrostatic pressure is greater than the formation pressure.
b- Annular pressure losses are creating an overbalance that prevents the well from flowing.
c- The pump pressure is greater than the hydrostatic pressure.
d- The pumps have failed

7. If light pill is pumped in the drill string and followed by 10 bbls original mud, What can it lead to after disconnect the Top Drive/Kelly if the light pill doesn’t come out from the nozzles ? (NO FLOAT VALVE IN THE STRING)

a- Reduction in the bottom hole pressure
b- Increase in the overbalance
c- Nothing will happen
d- Back flow from the drill string

8. With the pumps running continuously a heavy mud pill is circulated. When will bottom hole pressure start to increase (ignore dynamic pressure losses in the well)?

a. Once all the pill is in the annulus.
b. Once the pill starts to be displaced into the annulus.
c. As soon as the pill is pumped into the drill string.
d. Once all the pill is inside the drill string and is about to exit the drilling bit.

9. What is the reason for having a trip margin?

a- To allow for a level drop in the well if there are losses.
b- To compensate for possible swabbing effects during pulling out of the hole.
c- To create a safety margin in case the trip tank readings are inaccurate.
d- To create an overbalance when back on bottom drilling.

1. A-B                       4. B                          7. D
2. D                           5. A-C                      8. B
3. B                           6.                          9.

NB: We are very thankful to the well control community. We will be very happy to receive your comments or objections for sharing this content. Facebook page Drilling Course , E-mail: drilling.course@gmail.com