PRACTICE N°1

WELL CONTROL
PET-230

1. What is the difference between a gas influx in an oil-based mud and a gas influx in a water-based mud?

The oil-based mud is lighter.

b. More gas dissolves in an oil-based mud
More gas enters into a solution in a water-based sludge.
d. There is no difference.

2. Is the formation pressure 4410 psi at a true vertical depth of 9550 feet, the well is...?

Abnormally pressurized.
b. Normally pressurized.
c. Subnormally pressurized
d. All of the above.

A driller has pulled out 19 drill pipe joints (1710 feet) while traveling out of a well.
7260 feet the drill string gets stuck and breaks. The driller pulls out the 4185 feet of pipe above the
point where the pipe broke. At what depth is the fish stop?

1,365 feet
b. 5,895 feet
c. 3,075 feet
d. 4,185 feet

4. The 5" OD pipe; the socket fittings are 6.5" OD. The piping has an internal diameter of 10.192" and is
sitting at 4,000 feet PM, 3,690 feet MD. The BHA measures 1,000 feet. The well was drilled from the shoe to
total depth with an 8-1/2 inch drill bit. The well has a measured total depth of 8,200 feet and is vertical.
true 6,740 feet. What is the annular volume?

a. 336 bbls.
b. 483 bbls.
c. 273 bbls.
d. 756 bbls.

5. Using the above information. How many strokes will be needed to pump a tank up, if the output of the
The pump is 0.1429 bbls/strokes? (Assume 100% pump efficiency).

a. 2,240 strokes
b. 3,376 strokes
c. 3,420 strokes
5,040 strokes
e. 6,005 strokes

6. From the following warning signs, select 2 that are sure the well has a flow?

a. Increase in the temperature of the flow line

b. Increase in rotational torque
c. Increase in the return flow rate
d. Decrease in string weight
e. Increase in the level of the mud tanks
f. Increase in penetration speed

7. Shoe depth and test depth 7,960 feet PM and 7,690 PVV, The pressure of 'leak off test' was 1,000
psi, test mud weight 9.7 lbs/gal. Calculate the estimated density of the integrity fluid.
12.0 lbs/gal
12.2 lbs/gal
c. 12.4 lbs/gal
12.5 lbs/gal

8. What type of influx occurred, if there was a gain of 21.5 bbls in the mud tanks. What is the well diameter?
8.1/2" with 720 feet of 6.1/2" DE and P.CTPof 370 psi, PCTR of 670 psi and mud of 10.7 lbs/gal in the
well?

a. Gas (0.008-0.160 psi/inch)

b. Oil (0.388-0.400 psi/foot)
c. Fresh water (0.433-0.465 psi/foot)
d. Saltwater (0.465-0.500 psi/foot)
9. Calculate the maximum weight of the mud and the maximum permissible pressure at the surface in the following well:

12,345 PM
Profundidad de zapato 4,532 PM, 4,332 PVV
5" O.D. drilling pipe, 4.276" I.D.
Drilling boots 6" O.D, 2.3/4 ID.
Well diameter 8.1/2"
Mud weight during the test 9.2 lbs/gal
Test pressure 1,395 psi
Current mud 11.0 lbs/gal

a. 12.3lpg, 1,969 psi

b. 15.4 lpg, 991 psi
c. 15.3 lpg, 9.68 psi
d. 14.8 lpg, 515 psi

10. With the following information, determine the hydrostatic pressure drop when removing dry pipe from
well and it is not filling up.
Number of trios = 5.
Average length of each shot = 92 feet.
Pipe displacement = 0.0075 (bbl/foot).
Pipe capacity = 0.0773 (bbl/foot).
Weight of the sludge = 11.5 (lpg).
a. 245 psi
b. 276 psi
c. 30 psi
d. 409 psi
e. All of the above.

11. In a well of 7500 feet TVD, there are 365 feet of the annular space filled with gas with a gradient of 0.1 (psi/foot),
0.55 (psi/ft)
Calculate the closing pressure of the pipe (PCTR).
a. 145 psi
b. 527 psi
c. 345 psi
d. 400 psi

12. How many feet of filled pipe can be removed before losing 75 psi in bottom pressure when removing 5" rods?
that displace 0.0075 bbls/foot with 0.0173 bbls/foot of capacity, the 13 3/8” piping, of 0.1481 Bbls/Foot of
capacity, if the fluid has a density of 13.2 lpg?

543.25 FEET.

13. Given a well with a 9 5/8" casing, with an 8.755 inch inner diameter, where 15 pieces of 4 ½" are extracted,
31 feet per piece, and they displace 0.005002 bbls/feet. How many barrels are needed to fill the well?

2.32 BBLS.

14. How many embolladas are needed to fill the well from the previous exercise if the pump delivers 0.18 bbls/emb?

13 wrapped.

15. Calculate the density of the choking mud, and the final circulation pressure, with the current mud of 13.5 ppg, if the PCTP= 630
psi, and PCTR= 580 psi, at 12120 feet of measured depth (MD) and 11980 feet of true vertical depth (TVD), with flow pressure of
700 psi choke.

Drowning density = 14.51 lpg.

Final circulation pressure = 752.37 psi.

16. How many feet of dry piping can be extracted with a casing capacity of 0.05349 bbls/foot, a
pipeline displacement of 0.007593 bbls/foot, a pipe capacity of 0.01776 bbls/foot, with density
of the fluid of 19.6 lpg, to achieve a pressure drop of 75 psi at the bottom of the well?

444.80 feet.
 17. In a well, a surge occurs producing an increase in volume in tanks of 10 bbls with a density
current mud of 12.6 lpg. The well is closed and the following values are recorded: Closing pressure inside casing
(PCTR= 600 psi; Internal closure pressure of probe bars (PCTP) = 435 psi; Annular capacity = 0.029
bbls/pie. Determine the density of the upwelling.

3.40 lpg.

18. In a well where the exposed formation is at 3500 feet, an integrity test was performed with a mud of 9.20 ppg.
registering a surface pressure of 700 psi. Then drilling continued with a mud of 10.4 ppg when
A surge occurs with a casing pressure of 200 psi. What is the pressure increase for
above 200 psi to reach the fracture limit.

281.6 psi.

19. In a well that has a casing pressure of 450 psi, 10 shots of probe bars are introduced under pressure.
of 93 feet/shoot and a displacement of 0.02535 bbls/foot. During the maneuver, 36.2 bbls of mud are purged from
density 12.9 lpg; the inner diameter of the casing is 8.835" and the outer diameter of the wellbore is 5". Determine
What is the casing pressure increase?

164.24 PSI

20. The density of the well fluid is 11.8 ppg and the density needs to be raised, to balance the well, to 13 ppg;
There is a volume of 600 bbls of pits. How many bags of barite are needed to go from the
current fluid density to flood fluid density?

481 sx.

21. A well is drilled to a vertical depth of 8500 feet with a density of 9.5 ppg. Symptoms are observed.
from a surge, which closes the well and registers a pressure through the survey of 500 psi and a pressure
Through a column of 800 psi. Find out what the formation pressure is.

4699 PSI.

22. PRIOR INFORMATION FOR PROBLEMS 23-24-25-26 and 27.

Deviated well
Pipe 9 5/8"; 47 lb/ft, J-55; Pipe capacity = 0.0733013 bbls/ft; Shoe (PM) = 6152 feet; (PVV) = 5981
feet; estimated integrity density = 15 ppg; current mud density = 10 ppg; PCTP654 psi
increase in mud volume = 22bbls, Outer diameter of the well = 5"; 19.5 lb/ft with capacity of
=0.0177735 bbls/piece; Triplex pump = 0.1359119 bbls/container; Slow circulation rate = 60 containers/min and a
Slow circulation pressure or choke pressure of 853 psi.

23. What is the pressure limit at the wellhead before fracturing occurs?

1555 psi.

24. What is the required weight to drown the well with a margin equivalent to 100 psi additional to the internal pressure?
of polling?

11.22 lpg.

25. What is the initial circulation pressure?

1507 psi.

26. What is the final circulation pressure?

943.48 psi

27. How many pumpings will be required to fill the sampling and surface lines with mud of weight of
drowning, if the lines alone require 40 emboladas?

1808 blunders.
28. In a well, 360 feet of drill rods with an outer diameter of 5" are extracted incompletely, with a capacity of
0.0221858 bbls/piece. The casing has an outer diameter of 9 5/8” and an inner diameter of 8.441” with a capacity
from 0.0692424 bbls/foot, with the density of the mud being 12 ppg. What is the loss of hydrostatic pressure at the bottom?
of the same?

ANSWER = 7.06 PSI.

29. A well has a casing of 9 5/8” with an inner diameter of 8.835”, the measured depth of the shoe is 7620
feet; the inner diameter of the well is 8.5”. The drilling arrangement is constituted as follows =
drilling rods with an outer diameter of 4 ½" and a capacity of 0.01422 bbls/foot, the length of drilling rods
It is 11670 feet; outer diameter 6 ½” and inner diameter 2 ¾” with a measured depth (PM)
from 895 feet; the true vertical depth of the well (TVD) is 12050 feet and the measured depth (MD) of
12565 feet; the pump displacement is 0.147 bbls/emb and at 40 emb/min the slow circulation pressure or of
the choke is 625 psi; the current density of the mud is 11.6 ppg.
When drilling occurs, a surge is produced, the well is closed, and the following pressures are recorded:
PCTP= 350 psi and the PCTR= 700 psi.
Determine:
a. Drowning density. (ANSWER = 12.15 lpg)
b. Initial circulation pressure (ICP). (ANSWER = 975 psi)
Final circulation pressure (PFC). (ANSWER = 655 psi)
d. Surface embollies to drill. (ANSWER = 1174 emb)

30. DATOS DEL POZO: Profundidad medida 7846 pies, profundidad vertical verdadera 6600 pies, cañería de 13 3/8”
Measured shoe depth 5180 feet, true vertical depth of the shoe 4800 feet. A was made
LOT test in the shoe, using a density of 10.6 ppg, obtaining a surface pressure of 1000 psi.
Well diameter 12 ¼”.
5”OD pipe; 19.5 (lb/foot), capacity 0.01718 (bbl/foot).
Drill Collars 8"x3"; length 530 feet; capacity 0.0087 (bbl/foot).
Annular capacity between Drill Pipe and Pipe = 0.1353 (bbl/ft).
Annular capacity between Drill Pipe and open hole = 0.1215 (bbl/foot).
Annular capacity between DC and open hole = 0.0836 (bbl/foot).
When the well was closed, the following information was recorded:
PCTP= 340 psi.
PCTR= 410 psi.

Profit volume in tanks = 12 bbls.

Current mud density = 11.4 ppg.
Triplex Pump: 6 ½” cylinder, piston length 12”; efficiency 97%.
Flow reduced to 30 (epm), pressure 440 psi.
Calculate:
a. What is the density of the control mud.
b. How many strokes are needed to pump the control mud from the surface to the
trephine.
c. How many strokes are required to pump the mud from the drill bit to the shoe of the casing.
d. What is the total volume of the annular space.
e. What is the Maximum Allowable Surface Pressure (MASP) at the time of closing the well.
f. What is the new MASP when the control mud has been completely circulated through the well.
What is the initial circulation pressure.
What is the final circulation pressure when the control mud reaches the drill bit?