Note: the right answer is in BOLD format.
Q1) During primary well control, formation pressure is higher than hydrostatic pressure in the well.
a) True
b) False
Q2)What is meant with Primary Well Control?
a) Using the BOP to close in a flowing well.
b) Using the preferred wet! killing technique, which is the Driller ‘s Method.
c) Maintaining a hydrostatic pressure equal to or greater than the formation pressure ..
d) The use of pit volume and flow rate measuring devices to recognize a kick.
Q3)The drilling fluid gradient is changed to 0.137 bar /m / 0.603 psi/ft, What can you say about the state of the well?
I need to calculate the bottom hole pressure.
Pbh = 0.603 psi/ft x 8330 ftTVD = 5022 psi
Pbh < Pform in this case the well is UB.
a) The wen is overbalanced .
b) The well is in balance.
c) The well is underbalanced.
Q4) Consider a well with a depth of 10000 ft MO I 7500 ft TVO. The formation pressure at the bottom of the well is 4100 psi. Calculate the minimum drilling fluid density that is required to hold back the formation pressure. Give your answer in 1 decimal place.
4100 psi = 0.052 x 7500 x rhomud
rhomud = 10.5 ppg
Q5) Consider a well with a depth of 9250 ft MD / 8100 ft TVO. The reservoir at the bottom of the well has a pressure gradient of 0.500 psi/ft. Calculate the minimum drilling fluid density that is required to hold back the reservoir pressure. Give your answer in 1 decimal place.
Gres = 0.500 psi/ft
Pres = 0.500 psi/ft x 8100 ft = 4050 psi in this case 4050 psi = 0.052 x 8100 ft x rho mud
or rhomud = 0.500 psi/ft/0.052 = 9.62 ppg
Q5) Porosity is a measure of the ease with which fluids flow through porous rock.
a) True
b) False
Q6) Permeability is measured in Darcy or milliDarcy.
a) True·
b) False
see also Well Control Questions Part 1 & Part 2
Q7) Estimate what the normal formation pressure would be at a depth of 10675 ft TVD.
Pform = 0.433 psi/ft x 10675 = 4622 psi
Q8) If salt is dissolved in a fluid , its density increases.
a) True.
b ) False
Q9) The density of a fluid increases when its temperature increases.
a) True
b ) False
Q10) A formation is abnormally pressured when the pores in the subsurface are connected from surface down to the formation.
a) True
b) False
Q11) In undercompacted shales the porosity ;s higher than expected for a given depth.
a) True
b) False
Q12) Undercompacted shales tend to drill slower than expected.
a) True
b) False
Q12) What does abnormal pressure mean with regard to fluid pressure in the formation?
a) High density drilling fluid used to create a large overbalance.
b) Formation fluid pressure that exceeds t he normal formation fluid pressure.
C) The excess pressure that needs to be applied to cause leak-off in a normally pressured formation.
Q13) A gas bearing formation is overpressured by an artesian effect. Which of the following has created the overpressure?
a) Compaction of the formation from the over burden.
b) A formation water source located at a higher level than the rig floor.
c) The difference in density between the gas and the formation fluid.
Q14) What is the most common cause of abnormal formation pressure?
a) Depleted sands.
b) Carbonate layers.
c) Undercompaction of shales.
read also Drilling Company Questions & Answers
Q15) Match the following statements to one of the answers below:
1. Amount of space between the grains of rock
a) Permeability
b) Porosity
2. Rock ability to allow flow of formation fluid through it
a) Permeability
b) Porosity
Q16) At a depth of 400 m the formation pressure is 45 bar. The formation pressure can be considered as:
a) Abnormal
b) Normal
c) Subnormal
Q17) At a depth of 1315 ft the formation pressure is 653 psi. The formation pressure can be considered as:
a) Abnormal
b) Normal
c) Subnormal
Q18) The pressure at the crest of a gas filled reservoir is abnormal. What is the reason for this abnormal pressure.
a) The pressure at the crest is abnormal due to the artesian effect.
b) The pressure at the crest is abnormal due to the overburden pressure.
c) The pressure at the crest is abnormal due to the difference in density between the gas and the normal formation fluids.
Q19) Which gradient is used when calculating normal formation pressure?
a) 0.100 bar /m 0.433 psi/ft
b) 0. 105 bar/m 0.465 psi/ ft
c) 1.00 kgl t 8.33 PPS
Q20) Which statement is true for undercompacted shales?
a) The porosity is tower than expected for a given depth.
b) The porosity is higher than expected for a given depth.
Q21) When the temperature of a fluid increases its density decreases.
a) True
b) False
Q22) Which of the following statements is true? SELECT ONE ANSWER
a) To determine MAASP, the well is pressured up in uniform increments of 50 psi until leakoff is observed.
b) A leak-off test is carried out to determine the formation breakdown pressure.
c) The leak-off point is defined as the first point that deviates from the straight line.
d) MAA$P is defined as the sum of the hydrostatic pressure in the well + the surface pressure at leak-off.
e) If a gas influx enters the casing, the formation fracture pressure must be re-calculated.
f) A low volume, high pressure pump must be used to carry out a leak-off test.
Q23) A tea k-off test is carried out and teak- off occurs at a surface pressure of 650 psi. The casing shoe is set at 31 50 ft TVD_ The drilling fluid weight is 10.4 ppg.
A leak-off test is carried out and leak-off occurs at a surface pressure of 45 bar. The casing shoe is set at 951 m TVD. The drilling fluid weight is 1.15 kg / l.
a) Calculate MAASP. 650 psi
b) Calculate the formation fracture pressure (leak-off pressure at the casing shoe). 2353 psi
C) Express the formation fracture pressure as a gradient. 0.747 psi/ft
d) Calculate the maximum allowable drilling fluid density. 14.3 ppg
Q24) It is planned to perform a leak-off test. Which of the following actions have to be performed before the test is conducted? SELECT TWO ANSWERS
a) Circulate the drilling fluid to obtain a uniform weight and condition.
b) Drill out of the casing shoe and test the BOP stack against exposed formation and cement_
c) Spot a viscous LCM pill at bottom.
d) Drill 20 – 35 ft (6 – 10 m) of new formation.
e ) Run a calliper through casing and open hole.
Q25) A well has been killed with the Weight & Wait method. What can be said about MAASP?
a) MAASP is not valid anymore, a new leak-off test has to be performed.
b) MAASP hasn’t changed.
c) MAASP is now lower than before.
d) MAASP is now higher than before.
Q26) well is being killed and part of the gas influx has just been circulated into the casing. What can be said about MAASP.
a) MAASP is not valid anymore.
b) MAASP hasn’t changed.
c) MAASP is now lower than before.
d) MAASP is now higher than before.
Q27) You’re about to start a leak-off test. The drilling fluid weight in the hole is 12.0 ppg but the drilling fluid weigh t in the pits is 12.3 ppg. Which of the following should you do?
a) Pump down the annulus using drilling fluid from the trip tank.
b) Perform the leak-off test calculations using the 12.0 ppg to be on the safe side.
c) Perform the leak-off test calculations using the 12.3 ppg because then the MAASP has the lowest value.
d) Circulate and condition the drilling fluid until the weight in and out are the same.
Q28) What is the definition of MAASP?
a) The maximum BHP that can be allowed during a well kill operation.
b) The maximum drill pipe pressure that can be allowed during a well kill operation.
C) The surface pressure in excess of the drilling fluid hydrostatic pressure that if exceeded is likely to cause losses at the shoe.
d) The total pressure applied at casing shoe that can cause losses at shoe.
Q29) Which of the following are important for calculating the formation fracture pressure at the shoe?
SELECT THREE ANSWERS
a) Accurate pump strokes counter.
b) Accurate pressure gauge.
C) Exact drilling fluid density.
d) Accurate hole capacity.
e) Exact vertical depth of casing shoe.
Q30) How often should the MAASP be recalculated?
a) After every 500 ft drilled.
b) After every bit change.
c) After a change in drilling fluid weight.
Q31) Assuming a gas kick, which of the following increases the risk of exceeding MAASP during a well kill operation?
a) A small influx.
b) A large influx.
Read also Drilling Well Control Questions and Answers – part.2
Resources:
1. IWCF Drilling Well Control Level 3-4