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

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

Read: Applied Drilling Engineering, Ch.4 HW #14 Well Control – Driller’s due November 11, 2002

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

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)

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

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.

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.

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)

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

Variable Geometry Kick On Bottom - Well Shut In 200 psi 400 psi 4,000’ 9,500’ 10,000’ hB = 445’ PB = 5,700 psi

Variable Geometry 1. Calculate new BHP: 2. Calculate height of kick (check geometry). 3. Calculate density of kill mud:

4. Calculate the density of kick fluid: Variable Geometry 4. Calculate the density of kick fluid: How would you derive this equation?

Engineer’s Method - Gas Kick at surface Gas Bubble 10.0 lb/gal 10.38 lb/gal ho D* PB = const = 0.052 * r kill * depth

1. Calculate expansion of gas bubble 2. BHP = Press at top of kick + DP HYD,Annulus 3. Solve the resulting quadratic equation to get the pressure

BHP = PTOP + S (gi * hi ) gi = 0.052 * ri )

Well is Shut In Gas Bubble Will Rise ! Bubble Rise Velocity ?

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

Well Control Avoid kicks if possible Catch them early if they do occur Know how to control kicks if they do occur

Avoiding Kicks While Tripping: Keep the hole full. Avoid excessive surge pressures. Avoid excessive swab pressures

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.

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.

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 ].

Annular Fill-Up On Trips (i) Mud drains out through nozzles ………bbls (steel only) (ii) Nozzles are plugged ……… bbls (steel + mud)

Example (i) Vol. of steel only: (nozzles not plugged) From Table 1.6, actual weight in air is 20.60 lb/ft.

Example

Example Check: From Table 1.6,

Example (ii) Nozzles are plugged: From Halliburton book, internal capacity of 19.50 #/ft, 5” O.D. drillpipe is 0.01776 bbl/ft.

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?

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...

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

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.