PETE 411

Well 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 #14 Well 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 joint above the rotary 2. Shut down the

pump

3. Check for well

flow 4

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 ) 5

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 6

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 10

400 psi 200 psi Variable Geometry 4,000’

Kick On Bottom - Well Shut In

9,500’ 10,000’ P B = 5,700 psi h B = 445’ 11

Variable Geometry

1. Calculate new BHP: P B  ( 0 .

052 *  old * depth )  SIDPP 2. Calculate height of kick (check geometry).

3. Calculate density of kill mud:  kill  P B 0 .

052 * depth    SIDPP 0 .

052 * depth

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Variable Geometry

4. Calculate the density of kick fluid:  KICK   OLD  KICK  MUD  OLD   MUD     0 .

SICP 0 .

052 * SIDPP Kick 052    SIDPP Height * B Kick Height B   How would you derive this equation?

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Engineer’s Method -

h o D*

Gas Kick at surface

Gas Bubble 10.0 lb/gal 10.38 lb/gal P B P B  ( 0 .

052 *  * depth old = const = 0.052 *  ) kill  SIDPP * depth

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1. Calculate expansion of gas bubble V x  V B   P B P x     T x T B     Z x Z B   2. BHP = Press at top of kick +  P HYD,Annulus BHP  P x   P KICK   P m , old   P m , kill 3. Solve the resulting quadratic equation to get the pressure

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g i = 0.052 *



i

)

BHP = P TOP +

S (

g i * h i

)

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Gas Bubble Will Rise !

Well is Shut In Bubble Rise Velocity ?

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50 bbl kick 20 bbl kick 10 bbl kick 1,998 psi 1,266 psi 989 psi BARRELS OF KILL MUD PUMPED 18

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 (steel + mud) ……… bbls

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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.

 wt.

of 5 stds  20.60

lb ft ft * 93 std .

* 5 stds.

 9,579 lbs

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Example

Volume of steel  wt.

density  9 , 579 lbs 65 .

45 lbs/gal  146.36

gal  3.48

bbls  Fill up required  3.48

bbls of mud

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Example

Check: From Table 1.6, Displaceme nt  0 .

68    93 ft 90 ft    ( 5 stds ) bbls  3.51

bbls (close enough!

)

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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 .

Total capacity  0.01776

bbl ft   93 ft std * 5 stds  8 .

26 bbls

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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.

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