Chapter 4 Methods of Well Control

Question 1

Define Secondary Well Control?

Answer 1

It is well control after primary well control is lost or ahs failed to prevent formation fluids entering the wellbore. Typically, uses a BOP, to prevent the escape of wellbore fluids from the well.

Question 2

True or False: The Operator/Wellsite Supervisor is responsible for calculating the amount of overkill trapped within the system prior to commencing the circulation.

Answer 2

True.

Question 3

List the sequence for circulations out a kick using Drillers Method Step #1 - Execute?

Answer 3

• Open choke to initiate flow.
• Bring pump gradually to reduced speed (RS), holding CP at SICP plus overkill (If used) constant until the drill pipe pressure (DPP) stabilizes. Record stabilized DPP. Do not exceed MACP.
• Maintain constant DPP (barring any problems) until the influx is out of the well, or bottoms-up has been reached, whichever comes later.
• Stop the pump, holding casing pressure constant while closing the choke (trapping overkill if used).

Question 4

List the sequence for circulations out a kick using Drillers Method Step #2 - Execute?

Answer 4

• Open choke to initiate flow.
• Bring pump gradually to reduced speed (RS), holding CP at SICP plus overkill* (if used) constant. Record DDP as ICP.
• With choke adjustments, maintain the DPP at the previously calculated values on the DPP schedule. Do not exceed MACP.
• After kill density mud reaches the bit, record and maintain DPP at FCP.
• When kill density mud reaches surface, stop the pump and close choke.

Question 5

Why is it not recommended to bleed off overkill at the end of drillers step #1?

Answer 5

Due to the high risk of reducing EBHP below FP and allowing further influx into the wellbore.

Question 6

Why should you use a kill sheet designed for high angle wells to calculate the drill pipe pressure schedule?

Answer 6

Because a kill sheet designed for vertical wells will result in higher well pressures and possible fractured formations.

Question 7

List the sequence for circulations out a kick using Low Choke Method - Execute?

Answer 7

• Do not exceed MACP.
• Bring the pump near or up to the drilling rate and hold CP close to MACP.
• Mix barite as fast as possible up to 2 sacks per minute.
• Continue to circulate until the circulating DPP begins to increase due to increasing hydrostatic pressure from the weighted mud in the annulus.
• Circulate until annulus pressures are reduced sufficiently to use an alternate method of well control. Numerous circulations maybe necessary.

Question 8

List the sequence for circulations out a kick using Volumetric Method - Execute?

Answer 8

• Let the well stabilize.
• The allow migration to increase the SICP depending on well conditions. (For example: 500kPa OK + 200kPa PI).
• Slowly bleed off the equivalent volume of 200kPa of HP while holding the CP constant.
• Close the well and allow the CP to increase 200kPa.
• Repeat the above two steps according to the prepared Volumetric Method Kill Sheet until the gas is to surface and no more increase in CP.
• DO NOT exceed MACP.

Question 9

True or False: Increasing MACP is only valid until gas reaches the surface, at this time, as mud reaches the gas influx, the extra amount of MACP must be reduced.

Answer 9

True.

Question 10

With a small differential between SICP and MACP, and no barite on location what should be considered?

Answer 10

Increasing MACP is only valid until gas reaches the surface, at this time, as mud replaces the gas influx, the extra amount of MACP must be reduced or the shoe will fracture.

Question 11

Drillers Method Advantage?

Answer 11

Can verify accuracy of SIDPP after first circulation.

Question 12

Volumetric Method Advantage?

Answer 12

Successfully implemented when rig personal have been unable to circulate influx because of plugged nozzles.

Question 13

The driller has completed step 1 of the Driller’s Method with one circulation of the well. List four signs indicating the invading gas has been circulated out?

Answer 13

• No more flare,
• Tank volumes return to normal
• Casing gauge should read -SIDPP+OK
• Sound of mud passing through manifold
• Circ pressures remain constant
• Bottoms up time has expired.

Question 14

At the end of step 1 of the Drillers Method, the driller noticed that the pit volume had returned to normal but the flare was still lit. What does this indicate?

Answer 14

• Influx has not been completely circulated out,
• Possible losses in the hole,
• Pump efficiency.

Question 15

True or False: In a high angle well, the SIDPP and SICP can be 0 or even , with a kick in the lateral section?

Answer 15

True.

Question 16

Increase In MACP formula ?

Answer 16

Increase in MACP = Length of Bubble x (Mud Gradient - Gas Gradient) = kPa

Question 17

Define tertiary well control:

Answer 17

Third line of defense, where the formation cannot be controlled by primary or secondary well control(hydrostatic and equipment). This happens in surface or underground blowout situations.

Question 18

Plugged Nozzle Indicators & Solutions

Answer 18

Indicators:
DPP Increases drastically
CP reduces slightly with pump-stroke decrease
Solutions:
Shut down & re-establish accurate shut in pressures, then re-establish new circulating pressures.

Question 19

Unplugged Nozzle Indicators & Solutions

Answer 19

Indicators:
DPP Decrease
CP & pump strokes remain the same or increase slightly
Solutions:
Re-establish last accurate CP, and maintain new reduced DPP

Question 20

Bridge Indicators & Solutions

Answer 20

Indicators:
DPP Increases
Rapidly if gas is above bridge
Slowly if gas is below bridge
CP decrease and fluctuates
Pump speed decrease slowly
Fluid returns decrease
Flare decreases or dies. 
Solutions:
Work pipe without applying excessive pressure

Question 21

Plugged Choke Indicators & Solutions

Answer 21

Indicators: 
DPP & CP increase
Pump speed decreases slightly 
No tank increase
Flare goes out
Solutions:
Shut in well
Switch chokes

Question 22

Washed Choke Indicators & Solutions

Answer 22

Indicators:
DPP & CP decrease equally
Pump speed remains the same
Solutions:
Shut in well
Switch chokes