28 smd well control

7/29/2019 28 SMD Well Control

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Petroleum Engineering 411

Well Drilling

Lesson 28

SMD Well Control


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Subsea

Mudlift

Drilling( SMD )

Note

Pump

andReturnLine


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DESIGN PROJECTDESIGN PROJECT

Your PETE 411 Design Project

is Due in Dr. J-Ws Office by 5 p.m. on

Monday, Dec. 9, 2002

Monday, Dec. 2 is set aside for you to gettogether with your team mates to work on

the project during regular class hours.


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Contents -

g Review of Conventional Well Control

gKick Detection in SMD

g Kick containment in SMD

gBehavior of Real Gases in SMD Wells

g Well Control in SMD


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Kick Detection & Well Control- Review - Conventional -

g Kick Indication (what is a KICK?)

g Kick Detection (confirmation)

g Kick Containment (stop flow into well)

g Circulate Kick out of hole

g Increase Mud Weight in hole (if necessary)


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Circulate Kick out of hole

Keep the BHP constant throughout

Conventional Wait and Weight Method

BHP = Constant

Old

Mud

KillMud

Kick


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Gas Kick Behavior - Perfect Gas

Effect of Temperature Gradient

0

2,000

4,000

6,000

8,000

10,000

12,000

0 10 20 30 40 50 60 70

Kick Volume, bbls

Depth,

ft0.00 deg F/ft

0.02 deg F/ft

0.01 deg F/ft

Maximum Choke Pressure = 1,000 psia. BHP = 6,000 psia


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Z-Factor - In Shallow Wells

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000

Pressure, psig

GasCompressibilityFactor

(Z-Factor)

30 F

60 F

100 F

150 F

200 F

300 F

400 F

Gas Specific Gravity = 0.65 (S.G. of air = 1)


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Shallow Gas Kick - SummaryEffect of Temperature and Z-Factor

0

2,000

4,000

6,000

8,000

10,000

12,000

0 10 20 30 40 50 60 70

Kick Volume, bbls

Depth,

ft

Real Gas

Ideal Gas

PV = constant

0.02 deg F/ft


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Gas Kicks in Deep SMD Wells

Kick Volume vs. Depth

0

5,000

10,000

15,000

20,000

25,000

30,000

0 5 10 15 20 25 30

Kick Volume, bbl

Dep

th,

ft

As expected, most of

the expansion occurs

in the top 3,000 ft or so

MudLine

MudLift

Pump


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Kick Volume vs. Depth

0

5,000

10,000

15,000

20,000

25,000

30,000

0 5 10 15 20 25 30 35 40 45 50

Kick Volume, bbl

Depth,

ft

Gas Kicks in Deep SMD Wells

PV = constant

PV = ZnRT


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Gas Kick Behavior - Z-Factor

0.5

1.0

1.5

2.0

2.5

3.0

0 5,000 10,000 15,000 20,000 25,000

Pressure, psig

C

ompressibility

(Z-Factor)

30

60

100

150

200

300

400

Temperature,oF

Gas Specific Gravity = 0.65 (S.G. of air = 1)

pV=ZnRT


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MUDLIFTBOP

Subsea Mudlift Drilling System

SEAFLOOR

~SEAWATERHYDROSTATIC

PRESSURE

FLOATER

30,000

10,000

KICK

Surface Pump: Constant RateMudlift : Const. Inlet Press.

What next??


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Kick Detection and Control

640

650

660

670

680

690

700

-30 -20 -10 0 10 20 30

Time, minutes

Circulatio

nRate,gal/min

Kick begins

Kick Detected - - Slow down Seafloor Pump

SEAFLOOR PUMP

SURFACE PUMP


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15ATM

Influx has stopped and

pressures have stabilized



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16ATM


640

650

660

670

680

690

700

-30 -20 -10 0 10 20 30 40 50

Time, minutes

Circu

lationRate,

gal/min

Kick begins

Kick Detected - - Slow down Seafloor Pump

SEAFLOOR PUMP

SURFACE PUMP


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Standpipe Pressure vs. Time

0

1,000

2,000

3,000

4,000

5,000

0 200 400 600 800

Time, minutes

Pressure,p

si

SMD

ConventionalStart cir culating kick out of hole

Kill mud enters top of dril lpipe

Kill mud at bit


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Surface Choke Pressure vs. Time

0

200

400

600

800

1,000

1,200

1,400

0 100 200 300 400 500 600 700

Time, minutes

Pressure,psi

SIDPP

Start circulating

kick out

Top of kick at surface

Kick out of return line

Kill mud enters annulusSICP

CONVENTIONAL


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Pit Gain vs. Time

0

10

20

30

40

50

60

70

0 100 200 300 400 500 600 700

Time, minutes

PitVolu

meGain,

bbls

SMD

Conventional


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Pressure at the Sea Floor vs. Time

0

1,000

2,0003,000

4,000

5,000

6,000

7,000

8,000

0 200 400 600 800

Time, minutes

Pres

sure,ps

i

Conventional

SMDStart circulating kick out

Kick at seafloor

Kill mud enters annulus

Kill mudat seafloor

Pressure at inlet to Mudlift System


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Kick Detection Method Still Valid for SMD?

Pit Gain Still valid

Flow Rate Increase (Returns) Much Better

Well Flows With Rig Pump Off U-tubing ...

Fluid Fill-up on Trips More complicated

Increased Hook Load Still Valid

Drop in Standpipe Pressure Better

Drop in BHP - MWD Still Valid

Drilling Break Still valid

Decreased Mud Weight (Gas Cut) Still valid


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Well Control Summary

g Most Conventional kick detection methods

are still validg New differential flow rate method -

better - use with computer monitoring

g Lower standpipe pressure makes kick

detection easier and faster

g Conventional well control can be adapted

- with modifications


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Well Control Summary contd

g Not necessary to shut well in

g Seafloor pump controls the BHP

g Surface choke pressure generally

does not affect wellbore pressures

g Well control training will be essential !!


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General SummarySubsea Mudlift Drilling is a method that offers

potential for lowering drilling costs in very deepwaters.

( fewer casing strings, smaller rigs,

less time on location, larger hole )

The method utilizes one or more small-diameter

return lines from the seafloor to the surface. The

drillpipe is not inside a return line.


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Summary - contd

A mudlift system is used in the return line

thereby making a dual-density mud system

possible.

Wellhead pressure is maintained at seawater

hydrostatic, so well is dead at all times

Well control is quite similar to that in

conventional drilling with a riser- There are some real advantages:

higher margins, choke line P, etc.


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ATM


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ATM

MUDLIFT

U-Tubing in SMD

~SEAWATER

HYDROSTATICPRESSURE

BOP

STATIC

FLUID

LEVEL

FLOATER


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Static Pressures - SMD

SEAFLOOR

SEA WATER

HYDROSTATIC

PRESSURE

PRESSURE

DEPTH

ANNULUS AND RETURN LINE

DRILLSTRING PRESSURE

28 smd well control

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