1 PETE 411 Well Drilling Lesson 25 Well Control, cont’d

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PETE 411Well Drilling

Lesson 25

Well Control, cont’d

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Well Control, cont’d

Shut-in Procedures after Taking a Kick Kick Occurs While Drilling Kick Occurs While Tripping

Casing Pressures During Well Control Operations

Kick on Bottom Kick at surface

Kick Migration During Shut-in Conditions Kicks on Trips/ Wellbore Fillup

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Read:

Applied Drilling Engineering, Ch.4

HW #14Well Control – Driller’s

due November 11, 2002

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Controlling A Kick when On Bottom

Procedure:

1. Raise the kelly to clear the tool jointabove the rotary

2. Shut down the pump

3. Check for well flow

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Controlling A Kick when On Bottom

4. If well is flowing, immediately close the blowout preventer and shut in the well completely, (except on shallow gas kicks).

5. Notify supervisory personnel.

6. Read and record the stabilized shut-in drill-pipe pressure. (SIDPP)

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Controlling A Kick When On Bottom

7. Read and record the stabilized shut-in casing pressure (SICP)

8. Read and record the pit gain (pit-level increase = kick size)

9. Record the time

10. Record depth

11. Record mud weight

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Controlling A Well Kick While Making A Trip

1. Stop trip operations. Set slips with tool joint at rotary.

2. Install inside blowout preventer and release valve stem or close the valve if drill-stem valve is employed.

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Controlling A Well Kick While Making A Trip

3. Immediately close the blowout preventer and shut in the well completely (except on shallow gas kicks).

4. Install kelly, open drill-pipe valve, or pump through back-pressure valve.

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Controlling a Well Kick While Making A Trip

5. Notify supervisory personnel

6. Read and record the stabilized shut-in drill-pipe pressure or equivalent (SIDPP)

7. Read and record the stabilized shut-in casing pressure (SICP)

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Controlling A Well Kick While Making A Trip

8. Read and record the pit gain (Kick Size)

9. Record the time

10. Record the current well depth

11. Record the current mud weight

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Variable Geometry

Kick On Bottom

- Well Shut In

4,000’

9,500’

10,000’

400 psi 200 psi

PB = 5,700 psi

hB = 445’

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1. Calculate new BHP:

2. Calculate height of kick (check geometry).

3. Calculate density of kill mud:

SIDPP)depth**052.0(P oldB

depth*052.0

PBkill

depth*052.0

SIDPP

Variable Geometry

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4. Calculate the density of kick fluid:

How would you derive this equation?

Variable Geometry

BMUDOLDKICK HeightKick*052.0

SIDPPSICP

BMUDOLDKICK HeightKick*052.0

SIDPPSICP

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Engineer’s Method -

Gas Kick at surface

SIDPP)depth**052.0(P oldB PB = const = 0.052 * kill * depth

Gas Bubble

10.0 lb/gal

10.38 lb/gal

ho

D*

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1. Calculate expansion

of gas bubble

B

x

B

x

x

BBx Z

Z

T

T

P

PVV

kill,mold,mKICKx PPPPBHP

Annulus PHYD, kick of at top PressBHP .2

2. BHP = Press at top of kick + P HYD,Annulus

3. Solve the resulting quadratic equation to get the pressure

16BHP = PTOP + gi * hi gi = 0.052 * i

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Bubble Rise

Velocity?

GasBubble

Will Rise

!

Well is Shut In

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20 bbl kick

50 bbl kick

10 bbl kick

1,998 psi

1,266 psi

989 psi

CA

SIN

G P

RE

SS

UR

E,

psi

BARRELS OF KILL MUD PUMPED

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Well Control

Avoid kicks if possible

Catch them early if they do occur

Know how to control kicks if they do occur

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Avoiding Kicks While Tripping:

Keep the hole full.

Avoid excessive surge pressures.

Avoid excessive swab pressures

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Tripping Out of Hole

A good drilling engineer will always stay on the rig floor during the first 20 stands of a trip.

1. Make sure pipe is not pulled too fast.

2. Make sure annulus is kept full.

e.g. fill every 5 stands, and measure volume required to fill hole.

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Tripping Out Of Hole

If well is not taking enough fluid to replace volume of steel pulled from hole, fluid may have been swabbed into well.

Measure fluid volume to fill hole:

1. By counting pump strokes, or

2. By direct measurement from trip tank.

Note: The second method is best.

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Annular Fill-Up On Trips

Example 1

How much fill-up is required after pulling 5 stands of 5” OD, 19.5 #/ft drillpipe with extrahole tool joints?

[ Each stand is 93 ft long ].

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Annular Fill-Up On Trips

(i) Mud drains out through nozzles ………bbls

(steel only)

(ii) Nozzles are plugged ……… bbls (steel + mud)

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Example

(i) Vol. of steel only: (nozzles not plugged)

From Table 1.6, actual weight in air is 20.60 lb/ft.

lbs 9,579

stds. 5*.std

ft93*

ft

lb20.60stds 5 of wt.

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Example

mud of bbls 3.48required up-Fill

bbls 3.48

gal 146.36

lbs/gal 45.65

lbs 579,9

density

wt.steel of Volume

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Example

Check: From Table 1.6,

)enough! (close

bbls 3.51

bbls stds 5 ft 90

ft 93 68.0ntDisplaceme

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Example

(ii) Nozzles are plugged:

From Halliburton book, internal capacity of 19.50 #/ft, 5” O.D. drillpipe is 0.01776 bbl/ft.

bbls 26.8

stds 5*std

ft93

ft

bbl0.01776capacity Total

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Example

Volume of fill-up req’d = 3.48 + 8.26

= 11.74 bbls

How much did the fluid level drop?

How much did the BHP drop?

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Recommendations

Fill hole after each 5 stands of drill pipe when coming out of hole.

Fill hole after each stand of drill collars when coming out of hole.

When GIH after an extended period of time, break circulation gradually, at several different depths...

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Recommendations

Do not break circulation with bit and BHA just above the casing seat.

When breaking circulation, Start the pumps slowly, Rotate the drill string, Pick up on the drillstring at the same time

This will reduce the initial pressure required to get the mud moving

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MultiMedia Training Programs

To View these Programs on any Departmental Networked Computer:

1. Go to Network Neighbourhood

2. Select the computer marked “Juvkam-wold2”

3. The folder “Multimedia” contains TWELVE Multimedia Programs

Let me know if there are problems.