Questions Set 1

Practice questions for IWCF solve and ask doubts in comments.

Q 1. Which of the following possible warning signs indicate that well may go under balance? (Select two answers)
a. Increase in pump pressure.
b. Reduction in rate of penetration.
c. Change in cuttings size & shape.
d. Increase in weight on bit.
e. Increase in drilled gas percentage.

 

Q 2. Which one of the following is the first reliable indication that well is flowing?
a. Increase in torque.
b. Gas cut mud.
c. Decrease in pump pressure.
d. Increase in return flow.

Q 3. After recognizing a drilling break, what is the first action to be taken?
a. Make a flow Check
b. Circulate bottoms up
c. Continue drilling
d. Reduce pump speed

Q 4. What is meant by Primary Well Control?
a. The use of Blow out Preventers to close in a flowing well.
b. The slow circulating rate pressure used in the kill process.
c. The use of mud hydrostatic to balance fluid pressures in the formation.
d. The use of pit volume and flow rate measuring devices to recognize a kick.

Q 5. Will a kick always occur in the event of a loss of return?
a. No, it depends on the mud level in the annulus and the formation pressure.
b. No, it depends on the drill string weight reduction noted on the weight indicator.
c. Yes, losses will always occur above any potential kick zone.

Q 6. A well was flowing when in static condition (i.e. when not circulating) but was not flowing during the circulation. What could be the possible reason?
a. Pressure loss in drill string caused over balance while circulating at the bottom
b. Pressure loss across the bit caused over balance while circulating at the bottom
c. Pressure loss in the annulus caused over balance while circulating at the bottom

Q 7. Why the stand pipe pressure gauge shows little less pressure than pump pressure gauge?

a. Because of the gauge error.
b. Because of the hydrostatic head of the mud in stand pipe.
c. Because position of stand pipe pressure gauge is lower than pump pressure gauge.
d. Because of the dynamic pressure losses from pump to the stand pipe.

Q 8. Which of the following contributes to Equivalent Circulating Density?
a. Drill sting pressure losses
b. Annulus pressure losses
c. Drill bit pressure losses
d. Pressure loss from pump to the string

Q 9. Which of the following factors will increase the circulating pressure? (Select two answers)
a. Use of bigger size of bit nozzle
b. Increase in the length of BHA
c. Increase in the drilled depth
d. Decrease in the mud density during drilling

Q 10. Which one of the following causes of well kick is totally avoidable and is due to lack of alertness of driller?
a. Lost circulation
b. Gas cut mud
c. Abnormal pressure
d. Not keeping hole full

Q 11. Calculate the new slow circulating pressure at 30 spm if mud weight has been increased from 10 ppg to 13 ppg:
Recorded data:
SCR @ 30 spm : 400 psi
Drilled depth : 9587 ft
Mud density : 10 ppg
a. 333 psi
b. 520 psi
c. 480 psi
d. 525 psi

Q 12. While drilling, pump pressure was 3000 psi at 80 SPM with 11 ppg mud. What will be the approximate pump pressure, if the pump speed is reduced to 60 SPM & mud weight increased to 13 ppg?
a. 2,250 psi
b. 1,828 psi
c. 2,400 psi
d. 1,888 psi
e. 1,995 psi

Q 13. Which of following practices are likely to increase the chances of swabbing?
(Select three answers)
a. Pulling pipe slowly.
b. Maintaining high mud viscosity.
c. Pulling through tight spots with pumps off.
d. Pulling pipe fast.
e. Pulling through tight spots with pump on.

Q 14. A vertical well is drilled to a depth of 9,500 ft with 11.8 ppg mud, following are the recorded data:
WELL DATA:
Pump speed 70 spm.
Pressure losses in surface equipment 140 psi
Pressure losses in drill string 800 psi
Pressure losses in annulus 100 psi
Pressure losses at bit nozzles 1400 psi
a. Calculate Bottom Hole Pressure when well is static ______ psi
b. Calculate B H P when mud is circulated at 70 spm _____ psi
c. Calculate pump pressure when mud is circulated at 70 spm ______ psi
d. Calculate the equivalent circulating density ______ ppg

Q 15. In a well, during trip out swabbing was suspected. The flow check was negative and it was decided to run back to bottom (30 stands) checking for flow after lowering every 5 stands. The flow checks after 5, 10, 15 &s 20 stands showed no flow. But with stand number 25 back in the hole, the well was found to be flowing.
A What could be the most likely cause of the well flow?
a. Abnormal formation fluid pressure.
b. Derrick man mixed too light a slug prior to pulling out of the hole.
c. Running into the swabbed fluids caused hydrostatic pressure in annulus to drop.
d. ln the hurry, it was forgotten to slug the pipe while preparing for running back.

Q 16. While tripping out of the hole it is noticed that mud required to fill the hole is less than calculated. What action must be taken?
a. Shut the well in and circulate to clean the hole.
b. Flow check, if negative continue to pull out of the hole.
c. Flow check, if negative run back to bottom and monitor returns.
d. Flow check, if negative displace a heavy slug into annulus and continue pull out.

Q 17. Calculate with following data:
Drill Pipe Capacity = 0.0176 bbls/ft
Drill Pipe Metal Displacement = 0.0082 bbls/ft
Average Stand Length = 90 ft
a. Mud required to fill the hole per stand when pulled `dry‘ ____ bbls.
b. Mud required to fill the hole per stand when pulled `wet‘ ____ bbls.

Q 18. With following well data, calculate the reduction in bottom hole pressure if a driller has pulled out 15 stands of 5″ drill pipe dry, without filling the hole.
Drill pipe capacity – 0.0178 bbl/ft
Drill pipe steel displacement – 0.0080 bbl/ft .
Casing capacity – 0.0744 bbl/ft
Length of one stand – 88 ft
Mud weight – 13 ppg
Reduction In BHP – _____ psi

Post your queries in : http://www.knowenergysolutions.com/forum/ and topic is IWCF Discussion.

Answer key

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11 Responses to Questions Set 1

  1. admin says:

    Q1) IF we found that leak off test is not ok, then whats next step

    Ans 1) If Leak Off Test is not ok, this means cementing is not proper at casing shoe. You will have to go for cement repair. This can be done by cement squeez/plug job.

    Q2) IF we are running two mud pump at same spm, but spm of one mud pump is not remaining stable at same spm, what can be the reason?

    Ans 2) A very good question. Fluctuation or instability in pump SPM can tell you a lot about pump condition. Timely detection and fitting corrective action can save you rig time and money. Now coming to your question (actually I should dedicate a complete post for this, anyways in short)’unstable pump SPM’, fluctuations of pump SPM can be of two types. First, rapid fluctuations and second, slow and gradual fluctuations.

    Rapid Fluctuations: These are mainly due to mechanical problems which can be, worn out valve ring, valve, valve seat, piston ring and in worst case worn out wear plate and liner. You should stop the pump immediately and make a check for the things as mentioned in order. And if there are any indications of pump taking air then you should check the mud strainer in suction line.

    Gradual Fluctuations: These are mainly due to electrical and downhole problems. There may be problem in SCR, Motor Field or you are running near the load limit. Downhole problem like improper hole cleaning can also cause the SPM or pressure fluctuations. For electrical problems check the concerned electrical devices and for hole cleaning problem pump a lo-hi pill (low viscous mud followed by high viscous mud) and resume drilling after surface to bit time.

    Q3) In question 18 on your post http://www.knowenergysolutions.com/2012/03/iwcf-well-control-principles-and-practices-questions
    According to the formula given:
    13 x 0.052 x 0.0080 / (0.0744-0.0080) = 0.08144
    Now, 0.08144 X 15stnds X 88ft. = 107.508 p
    Yes, you got it right.

    Q4) What is the main factor that determines the rate of build-up to stabilized SIDPP & SICPP once the well is shut-in?
    a) Friction losses
    b)Gas migration
    c) Permeability

    Can someone plz answer and explain…

    Ans) For IWCF answer should be permeability because he is asking about initial pressure stablization (when well is just shut in) afterwards it would be due to gas migration. So if it shows up in exam mark permeability as correct answer as in IWCF answer key they use permeability as correct answer.

    Q5) One more practice question : Which of the following parameters might be affected by permeability of formation (select three answers)?
    a)SICP
    b)Bottom hole pressure
    c) SIDPP
    d)The time taken to stabilise the shut in pressures.
    e)Volume of influx

    Answer : a,d,e

    Q6) Select the good operating practices from the list (THREE) while drilling top hole section.
    a) Maintain as high overbalance as possible.
    b) Maintain high drilling rate
    c) Maintain mud density as low as possible.
    d) Continue to circulate when picking up for connection.
    e) Circulate at maximum rate to create highest possible ECD.
    f) Control drilling rate to avoid overloading the annulus with cuttings.

    Answer 6)
    I think answers are c,d,f because while drilling in top hole section : formation is weak so we have to keep mud density as low as possible, chances of shallow gas are there so continue to circulate when picking up for connection, controlling drilling rate to avoid overloading of annulus with cuttings.

    Q 7) Vertical well is drilled to 9000 ft. with 11.7 ppg mud.
    Pump speed: 70 spm.
    Pressure loss in surface equip.= 140 psi; press. loss in drill string = 800psi; press. loss in annulus = 100 psi; pressure loss at bit nozzle = 1400psi.

    a) Calculate BHP when mud is circulated at 70 SPM?
    b) Calculate eqvlt circulating density.

    BHP= hydrostatic pressure + annular losses
    = 0.052x 9000×11.7 + 100
    = 5575.6 psi
    ECD = APL/(.052*TVD) + mud wt
    = 100/(.052*9000) + 11.7
    = 11.913

    Q 8) When circulating out a kick in a deep well with a deep set casing shoe, the choke pressure approached MAASP while the influx is still in open hole. What is the most important action to take?

    Ans 8) You have to bleed through choke. SO that surface pressure goes below MAASP and ZUBIN can you like this website on facebook and ask your friends interested in IWCF to share their doubts so that we can create a group of interested people in IWCF field.

    In instrumentation section there will be questions on BOP’s, MGS, Inside BOp, FOSV, Rated working pressure,koomey control unit and may be 1-2 question on accumalator bottles. It will take us time to upload questions on instrumentation section but if you have any query you can post it here we will try our best to solve your queries.

    Q 10) All influx will be displaced from the hole at a pump rate considerably slower than that used while drilling. Select the correct reasons for this from the list below:

    One of the options is “To have minimum pressure being exerted on the open hole.”
    I think it will be one of the correct reasons, since slower pump rate means less annular pressure losses and hence less BHP. Is that correct?

    Ans10) Yes that is correct logic.!

    Q 11) While circulating out a kick, the pump speed is increased keeping SIDPP constant. What will happen to the BHP.
    a) Increase
    b) Decrease
    c) Remains Same
    (Plz explain the reason).

    Ans 10) According to me it should remain same as BHP = SIDPP + hydrostatic head of mud in string.
    As SIDPP is constant and IN iwcf we assume mud remains uniform in string so BHP should remain constant.

    people who asked question : Exactly what I thought. However the Transocean Q&A from where I got this question says it will DECREASE. I cannot understand how…

    Q11) A kick is being circulated out at 35 SPM, SIDP is 650 psi, SICP is 1050 psi. What would happen to BHP if pump is slowed down keeping SICP constant.
    a) Increase (b) Decrease (c) Stay the same
    Plz analyze…
    Reply
    Ans 11)

    Q12) One more gud question : Where is the mud loss first noticed during the time of drilling?
    a) on the mud pressure gauge
    b) on the return flow meter.
    c)In the mud pits P.V.T(Pit volume totalizer)
    d) From the loggers chart.

    Ans) on the return flow meter because it will tell instant change in the mud volume.

    Q13) Which of the following equipment may warn of increase in formation pressure while drilling overbalance? (3 ANSWERS)
    a) ROP meter
    b) Pump pressure guage
    c) Flow line temp guage
    d)SPM counter
    e) Gas Detector
    f) Return flow meter

    I think c,e,f. Plz confirm….

    Ans13) It is a) c) e) Return flow meter is a positive kick sign.See the difference between early warning sign and positive kick signs write if you dont get any material on them I will write more about it.

    Your Diagnosis of problems are correct
    Problem 1 : Nozzle plugging Symptoms : D/pipe Pr.: Increasing, Casing pressure :Constant
    Problem 2 : Choke plugged : D/ pipe pr.: Increses, Casing pressure: Increases
    Problem 3 : Choke Washout : D/ Pipe Pr : Decreases, Casing Pr : Decreases
    Problem 4 : Pump Failure : D/ Pipe Pr : Decreases, Casing Pr : Decreases ( No sound of pump in simulator)

    As while killing nozzle is plugged in question 1 so bottom hole pressure will remain same because we will calculate from annulus side because after nozzle plugging We hold Casing Pressure Constant and then bring pump down and Close Choke.Identify the problem and bring SIDP at original value. Keeping casing Pr. Constant bring pump to kill speed. Maintain new drill pipe pressure constant. Also change in reading in drill pipe pressure gauge is due to nozzle plugging ( As more pressure is lost in nozzle due to plugging) and as annular friction losses are same BHP will remain same,

    As choke is plugged in case 2 : Action to be taken are :
    Stop pump immediately and close HCR.
    Identify the problem bring the SIDP at original value.
    Line up alternate choke and HCR.
    Keeping casing Pr. Constant bring pump to kill speed.
    Maintain Drill pipe pressure constant.
    Because of choke plugging annular friction losses have increased by 200 psi in case 2 so BHP should increase by 200 psi.
    We are working on a kill sheet application which will help you in practicing kill sheet and also will post some questions on instrumentation section. In the meantime you can focus on BOP figures, koomey control unit figures,pipe ram figure according to course.

    Q14) Stack config: (from top to bottom) Annular=>> 5″ Pipe ram=>> Blind/Shear=>> 3 1/2″ Pipe ram =>> Drilling spool.
    With the drill string “hung-off” on the 31/2” rams, can the annular be repaired?
    Plz Explain “hung off”.
    Reply

    q15) With the drill string “hung-off” on the 31/2” rams, can the outer choke line valve be repaired?
    Yes/No

    q16) With the drill string “hung-off” on the 5” rams, can the annular be repaired?
    yes/no

    Ans 14) no as drilling spool is below 3 1/2″ ram outer choke line valve cant be repaired.

    Ans 15) yes as it is above on 5″ RAn from where drill string is hung off annular can be repaired.

    Ans 16) hung off means 3 1/2″ inch ram is closed and stringis hung on this ram BOP. so joints below it cant be repaired.
    Annular can be repaired.
    Modify message

  2. Anant says:

    Can somebody explain with formula……..
    Q 12. While drilling, pump pressure was 3000 psi at 80 SPM with 11 ppg mud. What will be the approximate pump pressure, if the pump speed is reduced to 60 SPM & mud weight increased to 13 ppg?
    a. 2,250 psi
    b. 1,828 psi
    c. 2,400 psi
    d. 1,888 psi
    e. 1,995 psi

  3. Can someone explain with formulae…

    While drilling, pump pressure was 3000 psi at 80 SPM with 11 ppg mud. What will be the approximate pump pressure, if the pump speed is reduced to 60 SPM & mud weight increased to 13 ppg?
    a. 2,250 psi
    b. 1,828 psi
    c. 2,400 psi
    d. 1,888 psi
    e. 1,995 psi

  4. Aboozar Fathinejad says:

    (80/60)^2*(11/13)=(3000/x), x=1994.31~1995 psi

  5. Ian Abbott says:

    Q 11) While circulating out a kick, the pump speed is increased keeping SIDPP constant. What will happen to the BHP.
    a) Increase
    b) Decrease
    c) Remains Same
    (Plz explain the reason).

    The Answer is DECREASE.

    If you increase the pump speed the pump pressure will naturally increase. So to maintain the SIDPP (should really be circulating pressure, only SIDDP when the pumps are off after a kick is taken) the choke operator must have opened the choke thus reducing the back pressure acting on the formation.

    It is tempting to increase pump speed when circulating out a kick at 30 spm but be patient, you should be in no hurry. While increasing and decreasing pump speeds, it is the casing pressure that should be monitored.

    • admin says:

      Hi Ian,
      Is this was your doubt or you wanted to explain the question. Anyways nice explanation if you have any doubts or questions you can discuss them here.
      Regards,
      Knowenergysolutions Team

  6. waheb says:

    q7; i think that the answer is d :
    the standpipe hydrostatic pressure also act on mud pump.

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