Theory Slides 2

1

KICK WARNING SIGNSKICK WARNING SIGNS

2

WHAT IS A KICK WARNING SIGN?

A WARNING SIGN TELLS YOU:-

THE WELL MAY BE GOING

“UNDERBALANCED”

OR

YOUR SAFETY MARGIN IS GETTING LESS.

3

Formation Pressure 9.0ppg

Mud Weight 10.0 ppg

What is happening?Drilling normally pressured shaleOverbalance

Warning Signs

4

Mud Weight 10.0 ppg



Pressure

and

Porosity

Increasing

Warning SignsWhat is happening?As the formation pressure gets closer to the mud weight, we will observe changes in;

ROPHole conditionGas levelsCuttings propertiesMud properties

5

Warning Signs

GEOLOGRAPH CHART

IncreasingDrill Rate

(ROP)

9850’

9855’

9860’

9.00

9.15

9.30

Increased drilling rateMud Weight 10.0 ppg



Pressure

and

Porosity

Increasing

6

Warning Signs

BIT

Increased drill string torque and drag

Mud Weight 10.0 ppg



Pressure

and

Porosity

Increasing

7

Warning SignsCuttings size & shape

Drilled cuttings

Cavings

Mud Weight 10.0 ppg



Pressure

and

Porosity

Increasing

8

Warning SignsFlowline temperature

NormalPressure

AbnormalPressure

Temperature Increase

Mud Weight 10.0 ppg



Pressure

and

Porosity

Increasing

9

Warning SignsShale density

NormalPressure

Increasing Formation Fluid

Pressure

Increasing Shale Density

9500’

9700’

9900’

10100’

9600’

9800’

10000’

10200’

Normal Trend Line

Shale

Shale

Shale

Sand

Sand

Sand

Mud Weight 10.0 ppg



Pressure

and

Porosity

Increasing

10

Warning SignsBackground & connection gas

5% 10%15%

1.002.003.004.005.006.00

Hours

1.002.003.004.005.006.00

Hours BACKGROUND GAS

CONNECTION GAS

Mud Weight 10.0 ppg



Pressure

and

Porosity

Increasing

11

Pressure Losses

Where does Pump Pressure come from??

12

Total Pump Pressure

PSI

= Surface Line friction

PSI

= Drillstring friction

PSI

= Bit (jet nozzle) friction

PSI

= Annulus friction

PSI

Total Pump Pressure

13

What Affects Pressure Loss

PSIPSI30 SPM 50 SPM

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PSIPSI30 SPM 30 SPM

10 ppg 15 ppg

15


PSIPSI

Low Vis. High Vis.

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PSIPSI50 SPM 50 SPM

Large nozzle Smell nozzle

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PSIPSI

Hole size

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Annulus Pressure Loss

30 SPMPSI

• Annulus pressure loss can be quite small.

• 50 -300 psi• This pressure acts on

hole wall and bottom• Increases with depth,

pump speed, hole size and pipe size.

19

Effect on Bottom Hole Pressure

90 SPMPSI

• If Annulus friction = 150 psi.• Mud Weight = 11 ppg• TVD = 8700 ft• What is the pressure on the

bottom of the hole?

= (11 x .052 x 8700) + 150

= 5126 psi

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• Gas at choke line, wellbore

fluids as shown on drawing.

• Using APL = 75psi, calculate

the circulating BHP.

• What is about to happen to the

casing pressure?

Bottom Hole Circulating Pressure

800psi

667psi

600psi

RKB 0

1800 ft10.8 ppg

mud

2000 ft12.0 ppg kill mud

3500 ft 10.0 ppg

mud

Subsea BOP

CL FL 200psi

(dynamic)

APL75 psi

BHP 5000 psiPf = 5000 psi

RKB 2500

RKB 1800’

RKB 6000’

RKB 8000’

00

21

Bottom Hole Pressure

Static Dynamic

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Connection Gas

PSI

3000 psi

BHP=7114 psi

11 ppgmud

Formation Pressure = 7000 psi12000’

AnnulusPressure Loss

= 250 psi

Mud CirculatingFormation Under Control

23

Connection Gas

BHP=6864 psi

Formation Pressure = 7000 psi12000’

Circulation StoppedFormation Not Under Control

PSI


= 0 psi

11 ppgmud

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Connection Gas

PSI

3000 psi

BHP=7114 psi

Formation Pressure = 7000 psi


= 250 psi

Mud CirculatingFormation Under Control

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Connection GasPSI

3000 psi

BHP=7114 psi

Formation Pressure = 7000 psi


= 250 psi Action to take•Increase mud weight.

•Control drilling.

•Minimize the connection time.

26

Warning SignsBackground & connection gas

5% 10%15%

1.002.003.004.005.006.00

Hours

1.002.003.004.005.006.00

Hours BACKGROUND GAS

CONNECTION GAS

Mud Weight 10.0 ppg



Pressure

and

Porosity

Increasing

27

Warning SignsWarning signsTell you overbalance

Major warning signs are:• Increasing ROP• Increasing torque/drag• Increased quantity/size of cuttings• Increased background gas• Connection gas• Increasing temperature• Decreasing shale density

What if we ignore them?

Mud Weight 10.0 ppg



Pressure

and

Porosity

Increasing

28

Warning SignsWhat is happening?• The formation pressure

is increasing and may lead to Underbalance

What will happen?

Mud Weight 10.0 ppg



Pressure

and

Porosity

Increasing


29

Warning Signs

• Underbalance

• Permeable formation

Kick

Mud Weight 10.0 ppg



Pressure

and

Porosity

Increasing


30

Warning SignsWhat happens?• Underbalance• Stuck• As shale has very low

permeability, the well cannot flow so the hole will collapse and we will get stuck.

Mud Weight 10.0 ppg



Pressure

and

Porosity

Increasing


31

Warning SignsWarning signsTell you overbalance

Major warning signs are:• Increasing ROP• Increasing torque/drag• Increased quantity/size of cuttings• Increased background gas• Connection gas• Increasing chlorides• Increasing temperature• Decreasing shale density

What should we do?

Mud Weight 10.0 ppg



Pressure

and

Porosity

Increasing

32

Warning Signs

What should we do?Mud Weight 10.0 ppg



Pressure

and

Porosity

Increasing

Flow Check

Circulate Bottoms Up

Raise Mud Weight

33

KICK INDICATORSKICK INDICATORS

34

PADDLE

GAUGEon

Driller’sConsole

Kick Indicators

35

PADDLE

GAUGEon

Driller’sConsole

Kick Indicators

36

Kick Indicators

GAUGEon

Driller’sConsole

37

GAUGEon

Driller’sConsole

Kick Indicators

38

Trip Tank

TRIP TANKPUMP

Normal Drop in LevelTrip

Tan

k Le

vel

Stands Pulled

Drop in Trip Tank Level

39

Kick Indicators

What are the indicators that the well is flowing?

• Increase in Flow Rate

• Increase in Pit Level

• Drop in pump pressure withan increase in spm

What Action Should Be Taken?

Check to see if well is flowing with the pump off.

40

KICK DETECTION IN OIL BASE MUD

•OIL AND GAS ARE HYDROCARBONS.

•GAS IS SOLUBLE IN OIL BASE MUD.

•GAS IS NOT SOLUBLE IN WATER BASE MUD.

•GAS IN SOLUTION DOES NOT EXPAND UNTIL NEAR SURFACE.

DRILLER WILL SEE PIT GAIN IN WBM EASIER

THAN OBM WITH THE SAME KICK SIZE.

41

KICK DETECTION IN OIL BASE MUD

42

Top hole drilling

43

The diverter system includes:

• Diverter - a low pressure annular preventer used to seal the wellbore from the flowline.

• Vent lines - large diameter piping used to flow the fluids downwind of the rig (port and starboard).

• Vent line valves - full opening valves used to select and isolate the desired vent line.

• Hydraulic control system - functions the diverter and automatically opens the selected vent line valve. Drive Pipe or

Conductor casingVent lines

FlowlineBell Nipple

Vent line Valves

Diverter

Large diameter drive or conductor pipe is usually installed below the mud line for spudding in an offshore location and a casing string is set and cemented at shallow depth for land locations. This pipe provides a seal capable of supporting the hydrostatic of the mud column from the base of the casing to the flow nipple outlet. The diverter system is installed on the drive or conductor casing.

The working pressure of the diverter and vent lines is not of prime importance, rather they are sized to permit high flow rate diversion of wellbore fluids while minimizing wellbore back pressure.

44Shallow Gas Blowout in the Gulf of Mexico

45

Problems• Shallow gas

– Can cause loss of rig due to explosion or capsizing.• Weak Formation• Losing the hole

– Might require re-spudding in a slightly different location

• Charged Formations

• Is it series problem???

Top hole drilling

46

SHALLOW GAS INCEDENT

47

SHALLOW GAS INCEDENT

48

49

What will happen as the formation is penetrated?

Shallow Gas

50

Shallow Gas

51

52

53

Top hole kick prevention• Drill pilot hole• Be careful when hole opening• Control drilling• Keep hole clean• Keep mud weights low to prevent losses• Pump out of hole

Shallow gas

54

Shut in procedures

55

Lined up with remote choke closed

Pick upShut down pumpsCheck flow - if flowing;

1-Close BOP2-Open HCR (hydraulic stack

valve)3. Record pressure

Hard shut in while drilling

56

Lined up with remote choke openPick upShut down pumpsCheck flow - if flowing;

1. Open HCR 2. Close BOP*3. Close remote choke4. Record pressure

Soft shut in while drilling

57

What is different?– String is open

• Valves and crossover required

• Safety valves– Full opening safety valve– Non return valve

Kicks while tripping

58

Full opening safety valve

TIW SMF

Kelly cock

59

Non return valve

Gray valveIBOP

60

Lined up with remote choke closed1. Install FOSV2. Close FOSV3. Close BOP*3. Open HCR6. Record pressure

Hard shut in while tripping

61

Lined up with remote choke open

1. Install FOSV2. Close FOSV3. Open HCR4. Close BOP*5. Close remote choke 6. Record pressure* API soft shut in states BOP (either Ram or Annular )

Soft shut in while tripping

62

Should only be considered on top hole where formation is weak.

1. Stop drilling (keep pumping)2. Activate Diverter With One Button- this will:

- Open vent line- Close flowline/shaker valve- Close diverter

3. Increase pump speed to maximum4. Pump mud 5. If well is still flowing after mud is pumped, line up and

pump water.

Diverting

63

SHUT IN PRACTICES

THINGS THAT DELAY SHUT IN.

• FLOW/PIT ALARMS NOT SET OR WORKING

• DRILL TOO FAR AFTER DRILLING BREAK

• LACK OF ‘SHUT IN’ TRAINING

• LACK OF MAINTENANCE + TESTING

• WAITING FOR INSTRUCTIONS

• ACCUMULATOR UNIT NOT WORKING

• NOT MONITORING TRIPS

Documents

Theory Slides 2