1. WELL CONTROL
By: Ridwan Durahman
Disampaikan pada pelatihan Pembinaan Keselamatan Kerja
Bogor, 9 May 2007
2. Blowout Statistics
83-% Influx was Gas
19-% Equipment Malfunction or Failure
Base Data: 425 Blowouts in TX, AL, MI, LA, OCS between 1960-1985
22%
22%
32%
24%
Drilling
Workover
Tripping
Other (Prod,
Cmt, P&A, log,
etc)
OPERATIONS
3. No Tahun Sumur Keterangan
1 1970 Mangunjaya,
ASAMERA
Saat melakukan twin well yang jaraknya 10 – 20 m terjadi creater masuk
kampung dan sekolah, tanah retak 500 – 600 m.
2 1975 JTB-44
Pertamina
Creater ke kampung yang keluar gas dan Lumpur, Relief well
3 1981 Paluh Tabuhan-29
Pertamina
Terjadi saat workover
Rig terbakar sehingga mengakibatkan seorang meninggal tertimpa rig.
4 1984 PSJ-1 Terjadi lost dan kick dan Blowout.
5 1984 Bekapai-7,
TOTAL
Menggunakan Barge, sumur sedang kick ditutup terus, kemudian Creater
Flatform 7 sumur runtuh.
6 1992 CMB-10
Pertamina
Ledakan di Rig N80-UE, karena Blowout
7 1996 JTB-201 Blowout di area Jatibarang CK-18 Karang Ampel
8 1997 Kuala-Simpang Blowout akibat Gas Kick, kemudian air dan lumpur keluar
9 1997
ATAKA-E
Unocal
Blowout di lepas pantai
10 2000
KE-5E
KODEKO
Blowout sumur
11 2001 RBT-01, PTM Blowout sumur Gas di Randublatung
12 2002 MBU-04 Terjadi Underground Blowout, terbentuk creater
13 2002
Tunu E-5 K1,
TOTAL
Blowout sumur Gas
Hilang Platform dan Swambarge Rig
14 2004
Rajawali-1
ENI Muara Bakau
Blowout sumur
15 2004
MSBY-01
KONDUR
Blowout sumur minyak
16 2006 BJP-1,LAPINDO Underground Blowout air dan lumpur
17 2006
Sukowati-5
PETROCHINA
Gas Kick
BLOWOUT in Oil&Gas Wells in Indonesia:
4. KICK AND FLUID FLOW
KICK = INFLUX OF UNWANTED
FORMATION FLUID INTO THE
WELLBORE
unwanted influx of a known amount of
formation fluid FLOWING from the
formation into the wellbore displacing
mud out of the wellbore
5. KICK AND FLUID FLOW (#2)
WELL PRESSURE CONTROL = The
control of formation fluid flow (kick) into
the wellbore
Two mandatory factors make fluid flows:
1. PRESSURE DIFFERENTIAL
2. MEDIA FOR FLUID TO PASS TROUGH
6. PHASE DEFINITION OBJECTIVE
PRIMARY
(First Line of Defense)
Control of kicks with
hydrostatic pressure
(HSP) only
Drill to total depth without
a well control event
SECONDARY
(Second Line of Defense)
Control of kicks with HSP
assisted by blowout
preventer equipment
Safety kill the kick without
the loss of circulation
TERTIARY
(Third Line of Defense)
An underground blowout Avoid a surface blowout.
Regain primary well
control
The ultimate goal of well pressure control is
to prevent a surface blow-out
THE 3-PHASES OF WELL CONTROL
9. THE PRIMARY CONTROL TOOL
HYDROSTATIC PRESSURE (HSP): The pressure developed by the height and density of
a non-moving fluid column.
PPG = LBS PER GALLON FLUID DENSITY
0.052 = PPG TO PSI/FT CONVERSION FACTOR
TVD = TRUE VERTICAL DEPTH (FT)
HSP PSI = MUD PPG x 0.052 x TVD FT
= 10.0 x 0.052 x 10,000
= 5,200 PSI HSP
To prevent formation fluid flow into the wellbore (kick), hydrostatic pressure must be at least
equal to the highest pressured permeable zone of the open hole.
10. Basic Equation of Well Control
Bottom Hole = Hydrostatic + Surface
Pressure* Pressure Pressure
BHP* = HP + SP
Example:
HP = 0.052 x TVD x MW
= 0.052 x 10000 x 10
= 5200 psi
Therefore:
BHP = HP + SP
= 5200 + 300
= 5500 psi
* For a static well.
10 ppg
5500
300
10000 ft.
12. FLUIDS
1. MUD or DRILLING FLUIDS
2. FUNCTION OF DRILLING FLUIDS
Transport cuttings
Control pressure
Wall support
Suspend cuttings
Suspend equipment, buoyancy
Lubrication
Transfer hydraulic energy
Media for logging
13. FLUIDS (#2)
3. SIDE EFFECTS OF USING DRILLING FLUIDS
Formation damage
Corrosion
Scaling
Lost circulation
Kick
Swabbing and Surging
Sticking
Environmental impact
Low ROP rate of penetration
Shale or Clay swelling
Hole stability – caving
Etc.
14. SWAB / SURGE PRESSURES
PRESSURE DEFINITION NOTES
SWAB
The piston effect of upward string
movement causing a decrease in
wellbore pressure which can
induce a kick
Maximum swab pressure occurs at the bit and is
equally imposed to the bottom of the wellbore.
As string motion is started, additional surge
pressure is imposed to break the gel strength of
the mud and accelerate the mud column.
TRIP MARGIN
Marginal over-balance pressure
(i.e., 300-500 psi) to compensate
for swab pressure.
The HSP overbalance is more often dictated by
hole stability (i.e., 800-1000 psi).
SURGE
The piston affect of downward
string movement causing an
increase in wellbore pressure.
Maximum surge pressure occurs at the bit and is
equally imposed the bottom of the wellbore.
As string motion is started, additional surge
pressure is required to break the gel strength &
accelerate the mud column.
PUMP
SURGE
The pump pressure required to
break the gel strength of the mud
and accelerate the mud column.
Pump surge pressure to break circulation can be
(in some cases) greater than the normal circulating
pressure.
15.
16.
17. KICK TOLERANCE
The maximum under balance kick load (ppg), considering an estimated kick volume,
the casing shoe can tolerate without fracturing
EVENT EFFECT ON KICK TOLERANCE
Casing shoe drill out Maximum kick tolerance for hole section
True vertical depth increase Decreases kick tolerance
Mud weight increase Decreases kick tolerance
KICK TOLERANCE APPLICATION
Indicates the next casing depth to maintain well control safety
Input to risk analysis if decision is made to drill ahead
18. KICK FUNDAMENTALS
1. PREDICTION OF FORMATION PRESSURE
PRE-DRILLING
History, Off – Set Data
Geology
Geophysics
WHEN DRILLING
Cuttings
Drilling Parameters
WOB, String Weight
Pump Speed, Pump Pressure
Drag, Torque
19. KICK FUNDAMENTALS (#2)
Mud Logging
Gas Reading
Shale Density
D-Exponent
Flow – Line Temperature
MWD + LWD
WHEN LOGGING & TESTING
Electric Logging
DST
20. KICK FUNDAMENTALS (#3)
2. CAUSE OF KICKS
Insufficient Mud Weight
Poor Tripping Practice (Surging When
RIH/Swabbing When POOH)
Failed to Keep The Hole Full
Drilling Charged Formation
Abnormal Formation Pressure
Lost Circulation (Loss of Hydrostatic Head)
Drilling Thru A Productive Well
Equipment Failure
Poor Cementing & Logging Practice
Poor Workover Practice
21. GUIDELINES FOR MAINTAINING HYDROSTATIC PRESSURE (HSP)
MUD WEIGHT MAINTENANCE
ACTION RESPONSIBILITY NOTIFY
Weigh and record mud weight in and out every 30
minutes during any circulating operation.
Shaker man
Derrick man
Driller
Mud Engineer
Monitor the well for signs of changing formation
pressure
Driller
Mud logger
Shaker man
Geologist
Drilling Engineer
Company Rep
Ensure mud weight is correct before drilling into
known high or low pressure zones
Company Rep
Mud logger
Toolpusher
Geologist
Drilling Engineer
Ensure a means of disposing of contaminated fluid to
avoid contaminating the mud system
Mud Engineer
Shaker man
Derrick man
Driller
Toolpusher
Company Rep
Ensure proper mud weight is used to fill the hole on
trips
Maintain pit valve seals to avoid accidental dilution
Maintain degasser capacity to handle full returns
Shaker man
Derrick man
Driller
Mud Engineer
22. MUD COLUMN MAINTENANCE
ACTION RESPONSIBILITY NOTIFY
Ensure proper hole hill during trips
Use a calibrated trip tank. Appoint a dedicated trip
tank man Record hole fill volumes during round trip
If the correct fill-up is not taken (swabbing indicated),
flow check the well. If not flowing, return to bottom
and circulate bottoms up.
If the correct displacement volume does not return
while tripping in, (lost circulation indicated), stop
tripping and observe the well.
If lost circulation occurs, pump water (WBM) or base
oil (OBM) down the annulus. If the well is flowing,
shut-in the well immediately.
Driller
Mud logger
Trip Tank Man
Company Rep
Driller Engineer
Toolpusher
Maintain mud box seals, ensure drain is plumbed to
the trip tank or annulus if filling with pump strokes.
A/D
Floor men
Company Rep
Toolpusher
Maintain hole full during non-circulating operations.
A/D
Driller
Company Rep
Toolpusher
23. SECOND LINE OF DEFENSE
KICK
The loss of hydrostatic pressure control of formation fluid flow into
the wellbore
SECONDARY
WELL CONTROL
The control of formation fluid flow by the uses of hydrostatic
pressure ASSISTED by blowout preventer equipment
24.
25.
26. KICK DETECTION
1. WHEN DRILLING
Drilling Break
Increase in Flow
Pit Gain (Returns to Surface after Circulation is
Stopped)
Change in Pump Pressure and Speed
Change in Torque, Drag and String Weight
Change in Amount, Size and Shape of Cuttings
Gas and Oil Shows
27. KICK DETECTION (#2)
2. WHEN TRIPPING
Improper Fill or Returns of Mud
Well Flowing
3. WHEN PERFORMING OTHER JOB
Well Flowing when Cementing
Well Flowing when Logging
29. CAUSES OF KICKS WHILE DRILLING
UNDER BALANCE KICK INDUCED KICK
Drilling into a permeable zone with a mud
weight insufficient to control formation
pressure
Lost Circulation
Light mud weight pumped down hole
Swabbing while working the string / making
connection
Core volume gas cut mud
30. INDICATIONS OF UNDER BALANCE KICKS
INDICATIONS NOTES RESPONSIBILITY NOTIFY
LOGGER TRENDS
INDICATE FP
INCREASE
d exponent decrease, Shale
density decrease, splintery shale
cuttings, connection/background
gas increase
Mud logger
Driller
Company Rep
Mud logger
Geologist
DRILLING BREAK
Indicates a new formation
exposed to the well. Under
balance kicks are usually
preceded by an abrupt ROP
change, increase or decrease.
Driller
Mud logger
Company Rep
Geologist
Toolpusher
WELL FLOW
As kick fluids flow into the
wellbore, the volume addition is
detected by the pit volume
totalizer (PVT).
Driller
Mud logger
Shaker Man
Derrick Man
Company Rep
Toolpusher
PIT VOLUME
GAIN
As kick fluids flow into the
wellbore, the volume addition is
detected by the pit volume
totalizer (PVT).
Driller
Mud Logger
Shaker Man
Derrick Man
Drilling Crew
Toolpusher
Co Rep
Mud Engineer
PUMP PRESSURE
DECREASE / SPM
INCREASE
Lower density kick fluid decrease
annulus hydrostatic pressure
allowing the drill string mud to U-
tube to the annulus.
Driller
Mud Logger
Toolpusher
Mud Eng
Derrick Man
31. INDICATIONS OF INDUCED KICKS
LOSS OF MUD WEIGHT
(LIGHT MUD PUMPED, SWABBED GAS, CORE GAS)
INDICATIONS NOTES RESPONSIBILITY NOTIFY
PUMP PRESSURE
DECREASE / SPM
INCREASE
Lower density kick fluid decreases
annulus hydrostatic pressure allowing
the drill string mud column to U-tube
to the annulus.
Driller
Mud Logger
Toolpusher
Derrick Man
Mud Eng.
WELL FLOW
Kick fluids displace mud from the
wellbore increasing return flow or
causing well flow with the pumps off.
Driller
Mud Logger
Shaker Man
Derrick Man
Drl Crew
Co Rep
Toolpusher
Mud Eng.
PIT VOLUME GAIN
As kick fluids flow into the wellbore,
the volume addition is detected by
the pit volume totalizer (PVT).
Driller
Mud Logger
Shaker Man
Derrick Man
Drl Crew
Co Rep
Toolpusher
Mud Eng.
INDICATIONS OF INDUCED KICKS
LOSS OF MUD WEIGHT
(LIGHT MUD PUMPED, SWABBED GAS, CORE GAS)
INDICATIONS NOTES RESPONSIBILITY NOTIFY
PUMP PRESSURE
DECREASE / SPM
INCREASE
Lower density kick fluid decreases
annulus hydrostatic pressure allowing
the drill string mud column to U-tube
to the annulus.
Driller
Mud Logger
Toolpusher
Derrick Man
Mud Eng.
WELL FLOW
Kick fluids displace mud from the
wellbore increasing return flow or
causing well flow with the pumps off.
Driller
Mud Logger
Shaker Man
Derrick Man
Drl Crew
Co Rep
Toolpusher
Mud Eng.
PIT VOLUME GAIN
As kick fluids flow into the wellbore,
the volume addition is detected by
the pit volume totalizer (PVT).
Driller
Mud Logger
Shaker Man
Derrick Man
Drl Crew
Co Rep
Toolpusher
Mud Eng.
INDICATIONS OF INDUCED KICKS
LOSS OF MUD WEIGHT
(LIGHT MUD PUMPED, SWABBED GAS, CORE GAS)
INDICATIONS NOTES RESPONSIBILITY NOTIFY
PUMP PRESSURE
DECREASE / SPM
INCREASE
Lower density kick fluid decreases
annulus hydrostatic pressure allowing
the drill string mud column to U-tube
to the annulus.
Driller
Mud Logger
Toolpusher
Derrick Man
Mud Eng.
WELL FLOW
Kick fluids displace mud from the
wellbore increasing return flow or
causing well flow with the pumps off.
Driller
Mud Logger
Shaker Man
Derrick Man
Drl Crew
Co Rep
Toolpusher
Mud Eng.
PIT VOLUME GAIN
As kick fluids flow into the wellbore,
the volume addition is detected by
the pit volume totalizer (PVT).
Driller
Mud Logger
Shaker Man
Derrick Man
Drl Crew
Co Rep
Toolpusher
Mud Eng.
32.
33. Maintain full circulation Maintain full circulation
Gas zone depletion may take several
hours or days
