well architecture rge 2008 jp szezuka

8/2/2019 Well Architecture RGE 2008 JP Szezuka

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JPS-04-08

Well Architecture

WELL ARCHITECTUREDESIGN


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Well Architecture

WHAT IS AN HOLE WELL ?

An Oil well is a bit more than just a hole in the Earth.

Due to the various Formations drilled

(nature, unstability, reservoirs, )

it is necessary to regularly protect the well bore.

For this the hole is covered using steel tubulars

called Casings which are furthermore Cemented.

The result is a telescopic succession of holes

ending at different depthsand having decreasing diameters.

This is what is called the Architecture of the well.

Various equipments are installed inside the last(s) casing(s)to allow Production of the Hydrocarbons.

This is the Completion phase.

An Oil well can be Vertical, Deviated or Horizontal.

It can be a Producer or an Injector.


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Well Architecture

Well Architecture Exemple & Conventional Representation

Hole 26 (660 mm)

Casing 20 (508 mm)

Hole 171/2 (660 mm)

Casing 133/8 (340

mm)

Hole 1214 (311 mm)

Casing 95/8 (224 mm)

Hole 81/2 (216

mm)

Casing 7 (178

mm)

Hole 53/4 (146 mm)

Casing 41/2 (114,3 mm)

Conductor pipe

50 m (164 ft)

Surface casing

240 m (787 ft)

Production casing

3300 m (10 826 ft)

Intermediary casing

2400 m (7 874 ft)

Production liner

3600 m (11 811 ft)


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JPS-04-08

Well Architecture

Casing Pipes

A casing pipe is composed of a body, threaded male at each of its extremities,

On one of the extremities is screwed a casing collar, threaded femelle x femelle,

used to connect the casing pipes between them.

Casing pipes exist in various sizes, weights and threads.


5/83JPS-04-08

Well Architecture

WHAT IS AN HOLE WELL ?

Open Hole

Annular

PreviousCasing

Casing Shoe

Cement

Cementation

The cement is mixed on surface,

pumped inside the casing

and displaced in the annular


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Well Architecture

OIL WELL

Well at end of drilling operations Perforated & Completed well


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Well Architecture

When designing a new well the first step is to determine its

ARCHITECTURE

i.e to determine the Phases of the well

Depth

Drilling size

Casing size

Casing characteristics


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Well Architecture

WELL ARCHITECTURE DESIGN

The well architecture depends on :

The well final depth ( From some hundred meters to 10 000 meters + )

The formation pressures & fracturation pressures.

The nature of the drilled formations ( Stability, Fluid bearing or not, )

Some formations may lead to case the hole (shales, salt, )

The shoe is better located in an impermeable formation.

The production programme.

DB - 11/01/2005


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Well Architecture


The well architecture design can be done in five steps :

1 - GATHER INFORMATION

2 - DETERMINE THE REQUIRED DRILLING FLUID DENSITIES

3 - DETERMINE THE CASING SHOE DEPTHS

4 - DETERMINE THE CASING SIZES AND DRILLING SIZES

5 CASING DESIGN


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Well Architecture


1 - GATHER INFORMATION

INFORMATIONS ON THE GEOLOGICAL BEDS (LITHOLOGY, TYPE)

EXPECTED DEPTHS OF THE DIFFERENT FORMATIONS AND RESERVOIRS

EXPECTED FORMATION PRESSURES

EXPECTED FRACTURATION PRESSURES

POTENTIAL ABNORMAL FORMATION PRESSURE

POTENTIAL FLUENT FORMATIONS


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Well Architecture

2.20

1000

2000

3000

4000

5000

Depth(meters)

Equivalent mud weight1.00 1.20 1.40 1.60 1.80 2.00

Pressure (bars)100 200 300 400 500 600 700 800 900 1000

Hydrostatic

Pressure

BRENT BAA2

DRAUPNE BAA5

HEATHER ABB5

AAB1

ABA1

ABB5

BAA2

BAA5

AAB2

AAA1

DST

LOT

Reference Wells

Pressure PlotPLIOCEN

E

OLIGOCENE

EOCENE

PALEOCENE

CENOMAN.

/MAASTR.I

CHIAN

ALBIAN

MID/UPJUR.A

SSIC

HORDALA

ND/NORDALAND

GROUP

ROGALAND

SHETLAND

GROUP

CROMER

VIKING

BRENT

Sea


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Well Architecture

1000

2000

3000

4000

5000

Depth(meters)

Equivalent mud weight1.00 1.20 1.40 1.60 1.80 2.00 2.20

Hydrostatic

Pressure

AAB1

ABA1

ABB5

BAA2

BAA5

AAB2

AAA1

DST

LOT

Reference Wells

Gradient PlotPLIOCENE

OLIGOCENE

EOCENE

PALEOCENE

CENOMAN.

/MAASTR.I

CHIAN

ALBIAN

MID/UPJ

UR.A

SSIC

HORDALAND/NORDALAND

GROUP

ROGALAND

SHETLAND

GROUP

CROMER

VIKING

BRENT

Sea


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Well Architecture

Formation Pressure Determination

The formation pressure can be estimated from various sources :

Drilling operations

Mud logging (connection gas, )

Pressure measurements from wire line logs

DST (Drill Stem Testing)

DST (Drill Stem Testing)

A DST allows to produce a well for a limited period of time,

i.e. to accurately measure the formation pressure

and to recover formation fluids.

This is done using the drillstring and one or two packers.

This can be done :

in open hole

in a cased perforated hole


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Well Architecture

Pumped volume (litres) Time (mn)

0 50 100 150 200 250 0 2 4 6 8 10

Pump stoppedLeak-off point

(Trend change)

Pr

essure(bar)

50

40

30

20

10

LOT (Leak Off Test)

A LOT allows to determine the formation strength

(Fracturation gradient) at a given depth

LOT Data

Depth 1010 mV

Shoe at 1000 mVMud weight 1.20 sg

Flow rate 50 lpm

Frac pressure 40 bars

Results

Pressure at shoe = 40 + (1000 x 1.20) / 10.2 = 157.7 bars

Frac gradient = 1.20 + (40 x 10.2) / 1000 = 1.61

or = (157.7 x 10.2) / 1000 = 1.61


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Well Architecture

LOT (Leak Off Test)

Objective of a LOT

LOT are carried out during the drilling phase of a well to:

Confirme the strength of the cement bond around the casing shoe Investigate the capability of the well to withstand additional pressure

below the casing shoe

Collect local data on formation strength

When to do a LOT

After drilling of the casing shoe

in order to determine the weak point of the coming hole

During drilling of the next hole section

After drilling of a weak zone

After drilling of a permeable zone

Before a transition zone

Before a important increase of mud density


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Well Architecture

LOT (Leak Off Test)

LOT Procedure

Drill out cement and 5 to 6 meters of new formation.

Circulate and condition mud, accuretely measure the mud density.

Pull the bit back inside the casing.

Make sure than the well is filled up.

Close the BOP on a drillpipe.

Use a high pressure, low volume pump (cement pump).

Line up calibrated pressure gauges (on the stand pipe).

Start pumping slowly (50 to 100 lpm) until the pressure builds up.

Record and plot the volume pumped against pressure.

The leak-off value is defined as the first point where the pressure

deviates from the observed trend.

Stop pumping and keep the well closed in and observe the pressure

If the pressure does not stabilize, this may be an indication of a

system link or a bad cement bond.

Bleed off the pressure and measure the volume of mud lost into the

formation.


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Well Architecture

Pressure (bars)100 200 300 400 500 600 700 800 900 1000


1000

2000

3000

4000

5000

Depth(m

eters)

Estimated

Fracturation

Gradient

Estimated

Formation

Pressure

BRENT BAA2

DRAUPNE BAA5

HEATHER ABB5

AAB1

ABA1

ABB5

BAA2

BAA5

AAB2

AAA1

DST

LOT

Reference Wells

PLIOCENE

OLIGOCENE

EOCENE

PALEOCENE

CENOMAN.

/MAASTR.I

CHIAN

ALBIAN

MID/UPJ

UR.A

SSIC

HORDALAND/NORDALAND

GROUP

ROGALAND

SHETLAND

GROUP

CROMER

VIKING

BRENT

Sea

W ll A hit t


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Well Architecture

Hydrostatic

Pressure


1000

2000

3000

4000

5000

Depth(m

eters)

AAB1

ABA1

ABB5

BAA2

BAA5

AAB2

AAA1

DST

LOT

Reference Wells

PLIOCENE

OLIGOCENE

EOCENE

PALEOCENE

CENOMAN.

/MAASTR.I

CHIAN

ALBIAN

MID/UPJ

UR.A

SSIC

HORDALAND/NORDALAND

GROUP

ROGALAND

SHETLAND

GROUP

CROMER

VIKING

BRENT

Sea

W ll A hit t


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Well Architecture


2 - DETERMINE THE REQUIRED DRILLING FLUID DENSITIES

TO CONTROL THE PORE PRESSURE OF THE DRILLED FORMATIONS

TO AVOID FRACTURATION OF THE ROCKS

TO AVOID SWELLING OF THE SHALES

TO AVOID FLUID LOSSES IN THE FORMATIONS.

THIS IS DONE USING SAFETY MARGINS DETERMINING THE MUD WINDOW.

THE REQUIRED MUD WEIGHT IS USUALLY SELECTED

AS THE MINIMUM WEIGHT ALLOWING TO CONTROL THE FORMATION PRESSURE.

W ll A hit t


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Well Architecture

1000

2000

3000

4000

5000

Depth(m

eters) Pressure (bars)100 200 300 400 500 600 700 800 900 1000


Estimated

Formation

Pressure

Estimated

Fracturation

Gradient

RequiredMud

Weight

Safety margin

(trip margin)

Safety margin(kick margin)

Mud

Window

PLIOCE

NE

OLIGOCENE

EOCENE

PALEOCENE

CENOMAN.

/MAASTR.I

CHIAN

ALBIAN

MID/UPJ

UR.A

SSIC

HORDAL

AND/NORDALAND

GROUP

ROGALAND

SHETLAND

GROUP

CROMER

VIKING

BRENT

Sea

Well Architecture


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Well Architecture


3 - DETERMINE THE CASING SHOE DEPTHS

DETERMINE WHERE THE REQUIRED MUD WEIGHT CAN BE SAFELY USED IN ORDER TO :

CONTROL THE FORMATION PRESSURE

AVOID FRACTURATION OF THE ROCKS

CONSIDERING ANY POTENTIAL PROBLEM (FLUID LOSSES, FLUENT FORMATIONS, )

THIS IS DONE FROM BOTTOM TO TOP OF THE WELL.

Well Architecture


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Well Architecture

Casing Shoe Depths Determination

Casing shoe depths are determined in order to be able to control a kick

without risk to fracture the drilled formation,

Then function of :

Expected formation and fracturation pressures,

Expected fluids,

Casing type,

Selected hypothesis (well full of gas or limited volumeof invasion (few m3),

Preferably set in an impermeable formation :

Shale,

Limestone,

Anhydrite,

This is done starting from the bottom of the well.

DB - 11/01/2005

Well Architecture


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JPS-04-08

Well Architecture


Estimated

Fracturation

Gradient

Estimated

Formation

Pressure

Required

MudWeight

Depth to be reached

Casing required

at this depth

Well Architecture


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JPS-04-08

Well Architecture


Depth to be reached

Estimated

Formation

Pressure

Estimated

Fracturation

Gradient

Gas

gradient

Casing required

at this depth

Well head pressure

If well full of gas

Well Architecture


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JPS-04-08

Well Architecture

PLIOCE

NE

OLIGOCENE

EOCENE

PALEOCENE

CENOMAN.

/MAASTR.I

CHIAN

ALBIAN

MID/UPJUR.A

SSIC

HORDAL

AND/NORDALAND

GROUP

ROGALAND

SHETLAND

GROUP

CROMER

VIKING

BRENT

Sea

1000

2000

3000

4000

5000

Depth(m



5060 mV

4200 mV

3200 mV

1300 mV

200 mV

Well Architecture


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Well Architecture


4 - DETERMINE THE CASING SIZES AND DRILLING SIZES

ACCORDING TO REQUIRED PRODUCTION EQUIPMENT

USING AVAILABLE CASING (STANDARD SIZES WHENEVER POSSIBLE)

Well Architecture


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Well Architecture

1000

2000

3000

4000

5000

Depth(m



5060 mV

4200 mV

3200 mV

1300 mV

200 mV

Liner 7

at 5060 mV

Csg 95/8

at 4200 mV

Csg 133/8

at 3200 mV

Csg 185/8

at 1300 mV

Csg 24

at 200 m

Phase 22

Phase 171/2

Phase 121/4

Phase 81/2

Phase 6

PLIOCE

NE

OLIGOCENE

EOCENE

PALEOCENE

CENOMAN.

/MAASTR.I

CHIAN

ALBIAN

MID/UP

JUR.A

SSIC

HORDAL

AND/NORDALAND

GROUP

ROGALAND

SHETLAND

GROUP

CROMER

VIKING

BRENT

Sea

Liner 41/2 at TD

Well Architecture


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Well Architecture


5 CASING DESIGN

SELECT THE MECHANICAL RESISTANCE OF THE CASING PIPES

(GRADE, WEIGHT AND THREAD)

IN ORDER TO SATISFY THE VARIOUS CONDITIONS THAT THE CASING WILL MEET.

TRACTION

BURST PRESSURE

COLLAPSE PRESSURE

CONSIDERING THE CEMENTING PROGRAMME

CONSIDERING THE PRODUCTION PROGRAMME

Well Architecture


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Well Architecture

Casing Pipes Characterisation

External diameter (body) (inches or mm)

Linear weight (body) (pounds/foot - lbs/ft - # or kg/m)

Grade (a letter followed by a number)

(The number indicates the steel minimum yield strength in kpsi)

Type of Connection (API, BTC,VAM,)

Example:

133/8 40.0 lbs/ft K55 BTC

All casing pipes characteristics are regulated by the American Petroleum Institute API 5CT

Well Architecture


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JPS-04-08

e c tectu e


Well Architecture


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2.20

1000

2000

3000

4000

5000

Depth(m

eters)

Equivalent mud weight1.00 1.20 1.40 1.60 1.80 2.00

Pressure (bars)100 200 300 400 500 600 700 800 900 1000

Hydrostatic

Pressure

BRENT BAA2

DRAUPNE BAA5

HEATHER ABB5

AAB1

ABA1

ABB5

BAA2

BAA5

AAB2

AAA1

DST

LOT

Reference Wells

PLIOCENE

OLIGOCENE

EOCENE

PALEOCENE

CENOMAN.

/MAASTR.I

CHIAN

ALBIAN

MID/UP

JUR.A

SSIC

HORDALAND/NORDALAND

GROUP

ROGALAND

SHETLAND

GROUP

CROMER

VIKING

BRENT

Sea

Well Architecture


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Pressure (bars)100 200 300 400 500 600 700 800 900 1000


1000

2000

3000

4000

5000

Depth(m

eters)

Estimated

Fracturation

Gradient

Estimated

Formation

Pressure

BRENT BAA2

DRAUPNE BAA5

HEATHER ABB5

AAB1

ABA1

ABB5

BAA2

BAA5

AAB2

AAA1

DST

LOT

Reference Wells

PLIOCENE

OLIGOCENE

EOCENE

PALEOCENE

CENOMAN.

/MAASTR.I

CHIAN

ALBIAN

MID/UP

JUR.A

SSIC

HORDALAND/NORDALAND

GROUP

ROGALAND

SHETLAND

GROUP

CROMER

VIKING

BRENT

Sea

Well Architecture


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JPS-04-08

1000

2000

3000

4000

5000

Depth(m



Estimated

Formation

Pressure

Estimated

Fracturation

Gradient

Mud

Window

Safety margin

(trip margin)

Safety margin

(kick margin)

PLIOCENE

OLIGOCENE

EOCENE

PALEOCENE

CENOMAN.

/MAASTR.I

CHIAN

ALBIAN

MID/UP

JUR.A

SSIC

HORDA

LAND/NORDALAND

GROUP

ROGALAND

SHETLAND

GROUP

CROMER

VIKING

BRENT

Sea

Well Architecture


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JPS-04-08

1000

2000

3000

4000

5000

Depth(m



Estimated

Formation

Pressure

Estimated

Fracturation

Gradient

Required

Mud

Weight

Safety margin

(trip margin)

Safety margin

(kick margin)

Mud

Window

PLIOCENE

OLIGOCENE

EOCENE

PALEOCENE

CENOMAN.

/MAASTR.I

CHIAN

ALBIAN

MID/UP

JUR.A

SSIC

HORDA

LAND/NORDALAND

GROUP

ROGALAND

SHETLAND

GROUP

CROMER

VIKING

BRENT

Sea

Well Architecture


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1000

2000

3000

4000

5000

Depth(m



5060 mV

The BRENT reservoir has a

lower pressure gradient

This requires to set a casing

at its top to be able to decrease

the mud density.

> A Casing (/ Liner) will be set

at 5060 mV.

> A Liner will cover the BRENT

to 5450 mV TD.

PLIOC

ENE

OLIGOCENE

EOCENE

PALEOCENE

CENOMAN.

/MAASTR.I

CHIAN

ALBIAN

MID/UP

JUR.A

SSIC

HORDA

LAND/NORDALAND

GROUP

ROGALAND

SHETLAND

GROUP

CROMER

VIKING

BRENT

Sea

Well Architecture


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JPS-04-08

1000

2000

3000

4000

5000

Depth(m



5060 mV

4200 mV

A 2.07 mud weight is required

to drill this section.

This gradient intercept the

fracturation line at 4200 mV.

> A Casing must be set

at 4200 mV.

PLIOC

ENE

OLIGOCENE

EOCENE

PALEOCENE

CENOMAN.

/MAASTR.I

CHIAN

ALBIAN

MID/UP

JUR.A

SSIC

HORDA

LAND/NORDALAND

GROUP

ROGALAND

SHETLAND

GROUP

CROMER

VIKING

BRENT

Sea

Well Architecture


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JPS-04-08

1000

2000

3000

4000

5000

Depth(m



5060 mV

4200 mV

3200 mV

A 1.80 mud weight is required

to drill this section.

This gradient intercept the

fracturation line at 3200 mV.

> A Casing must be set

at 3200 mV.

PLIOC

ENE

OLIGOCENE

EOCENE

PALEOCENE

CENOMAN.

/MAASTR.I

CHIAN

ALBIAN

MID/UP

JUR.A

SSIC

HORDA

LAND/NORDALAND

GROUP

ROGALAND

SHETLAND

GROUP

CROMER

VIKING

BRENT

Sea

Well Architecture


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JPS-04-08

1000

2000

3000

4000

5000

Depth(meters) Pressure (bars)100 200 300 400 500 600 700 800 900 1000


5060 mV

4200 mV

3200 mV

1300 mV

There is a risk of mud losses

in the OLIGOCENE.

A 1.22 mud weight is

required to drill the

abnormally pressured

EOCENE.

> This requires to cover theOLIGOCENE

A casing must be set after

penetration in the EOCENE

(+/- 1300 mV)

PLIOC

ENE

OLIGOCENE

EOCENE

PALEOCENE

CENOMAN.

/MAASTR.I

CHIAN

ALBIAN

MID/UP

JUR.A

SSIC

HORDA

LAND/NORDALAND

GROUP

ROGALAND

SHETLAND

GROUP

CROMER

VIKING

BRENT

Sea

Well Architecture


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JPS-04-08

PLIOC

ENE

OLIGOCENE

EOCENE

PALEOCENE

CENOMAN.

/MAASTR.I

CHIAN

ALBIAN

MID/UP

JUR.A

SSIC

HORDA

LAND/NORDALAND

GROUP

ROGALAND

SHETLAND

GROUP

CROMER

VIKING

BRENT

Sea

1000

2000

3000

4000

5000



5060 mV

4200 mV

3200 mV

1300 mV

200 mV

A Conductor pipe with a

50 m penetration in the sea bed

is required.

> It must be set at 200 mV

Well Architecture


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JPS-04-08

1000

2000

3000

4000

5000



5060 mV

4200 mV

3200 mV

1300 mV

200 mV

Liner 7

at 5060 mV

Csg 95/8

at 4200 mV

Csg 133/8

at 3200 mV

Csg 185/8

at 1300 mV

Csg 24

at 200 m

The Production Departement

requires a 41/2 liner

in the reservoir.

> This allows to determine the

above casing sizes

(using standard sizes).

> The 7 will preferably be a liner.

PLIOC

ENE

OLIGOCENE

EOCENE

PALEOCENE

CENOMAN.

/MAASTR.I

CHIAN

ALBIAN

MID/UP

JUR.A

SSIC

HORDA

LAND/NORDALAND

GROUP

ROGALAND

SHETLAND

GROUP

CROMER

VIKING

BRENT

Sea

Liner 41/2 at TD

Well Architecture


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JPS-04-08

Casing & Drilling Sizes

143/4

16

105/8

113/4

77/8

85/8

65/8

43/4

4

20

24

143/4

16

97/8 105/883/4

113/4103/4

75/8 85/8

5

61/4 61/2

24

30

171/2

20

121/4

95/8

133/8

51/2

77/8

26

185/8

171/2

185/8

133/8

95/8

81/2

7

6 61/857/8

41/2

121/4

20

Well Architecture


42/83

JPS-04-08

1000

2000

3000

4000

5000



5060 mV

4200 mV

3200 mV

1300 mV

200 mV

Liner 7

at 5060 mV

Csg 95/8

at 4200 mV

Csg 133/8

at 3200 mV

Csg 185/8

at 1300 mV

Csg 24

at 200 m

Phase 22

Phase 171/2

Phase 121/4

Phase 81/2

Phase 6

PLIOC

ENE

OLIGOCENE

EOCENE

PALEOCENE

CENOMAN.

/MAASTR.I

CHIAN

ALBIAN

MID/UP

JUR.A

SSIC

HORDA

LAND/NORDALAND

GROUP

ROGALAND

SHETLAND

GROUP

CROMER

VIKING

BRENT

Sea

Liner 41/2 at TD


43/83

Well Architecture


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JPS-04-08

Hydrostatic

Pressure


1000

2000

3000

4000

5000

Depth(m

eters)

AAB1

ABA1

ABB5

BAA2

BAA5

AAB2

AAA1

DST

LOT

Reference Wells

PLIOC

ENE

OLIGOCENE

EOCENE

PALEOCENE

CENOMAN.

/MAASTR.I

CHIAN

ALBIAN

MID/UPJUR.A

SSIC

HORDALAND/NORDALAND

GROUP

ROGALAND

SHETLAND

GROUP

CROMER

VIKING

BRENT

Sea

Well Architecture


45/83

JPS-04-08Equivalent mud weight

1.00 1.20 1.40 1.60 1.80 2.00 2.20

1000

2000

3000

4000

5000

Depth(meters)

Hydrostatic

Pressure

PLIOCENE

OLIGOCENE

EOCENE

PALEOCENE

CENOMAN.

/MAASTR.I

CHIAN

ALBIAN

MID/U

PJUR.A

SSIC

HORD

ALAND/NORDALAND

GROUP

ROGALAND

SHETLAND

GROUP

CROMER

VIKING

BRENT

Sea

Well Architecture


46/83

JPS-04-08Equivalent mud weight

1.00 1.20 1.40 1.60 1.80 2.00 2.20

1000

2000

3000

4000

5000

Depth(meters)

5060 mV

4200 mV

3200 mV

1300 mV

200 mV

PLIOCENE

OLIGOCENE

EOCENE

PALEOCENE

CENOMAN.

/MAASTR.I

CHIAN

ALBIAN

MID/U

PJUR.A

SSIC

HORD

ALAND/NORDALAND

GROUP

ROGALAND

SHETLAND

GROUP

CROMER

VIKING

BRENT

Sea

Well Architecture


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CASING DESIGN

Well Architecture


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CASING DESIGN

Conductor pipe

Surface casing

Production casing

Intermediary casing

Production liner

A column of casings is composed of several sections called :

- Conductorpipe

- Surface casing

- Intermediate casing(s)

- Production casing or liner(s)

Each section must :

- Enter in the previous casing & open hole

- Allow the next bit to go down

- Resists to Burst (Kick, Production)

- Resists to Collapse (Fluent formations, Empty column)

- Resists to Traction (Running in, Tests)

- Resists to Buckling (Running in)

Well Architecture


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JPS-04-08

CASING DESIGN

Once the shoe depths and the casing sizes are determined,

each casing must be dimensionned in order to resist to the

Loading conditions depending on the type of section.

For each size of casing exist :

Various Grades

Various Nominal Weight (pipe wall thickness)

Various type of Threads

Different Safety coefficients will be used according to the type of section.

A casing column may be composed of different section of pipes.

Well Architecture


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Casing Pipes Characterisation

External diameter (body) (inches or mm)

Linear weight (body) (pounds/foot - lbs/ft - # or kg/m)

Grade (a letter followed by a number)

(The number indicates the steel minimum yield strength in kpsi)

Type of Connection (API, BTC,VAM,)

Example:

133/8 40.0 lbs/ft K55 BTC

All casing pipes characteristics are regulated by the American Petroleum Institute API 5CT

Well Architecture

C i G d & M i Ch t i ti


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Casings Grades & Main Characteristics

1351251201051001009595957560Tensile Str mini Mpa

1501401351101051109590808080Yield maxi kpsi

1251101059590808075555540Yield mini kpsi

Q125P110P105C95C90N80L80C75K55J55H40Grade

From the Drilling Data Handbook

Well Architecture

St d d C i C ti


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Standard Casing Connections

API Round Thread & Coupling

Buttress Thread & Coupling

VAM Coupling (Buttress Thread)

Well Architecture

CASING DESIGN


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CASING DESIGN

Conductor pipe

Objective:

Maintain the surface formations.

Length :

from a few meters to some tenths of meters.

Cimentation :

To surface (complementary cementation if necessary)

Often installed before the arrival of the drilling rig

(Civil works, hammering or drilling)

Well Architecture

CASING DESIGN


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CASING DESIGN

Surface Casing

Objectives :

Maintain the formations

Protect the hole from these formations

Protect the aquifer formations

Support the BOPs

Support the next casings

Length :

from a few meters to some hundreds of meters.

Cimentation :

To surface

Well Architecture

CASING DESIGN


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CASING DESIGN

Intermediary Casing(s)

Objectives :


Solve potential problems between the formations

o Pressure, too high or too low

o Salt and/or Fluent formations

Length :

As required

Cimentation :

To surface or partial (stage cementation if necessary)

Well Architecture

CASING DESIGN


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CASING DESIGN

Production Casing(s) or Liner(s)

(Any casing or liner exposed to the production operations)

Objectives :


Protect the reservoir

Allows to install the production equipment

Length :

As required

Shoe at top reservoir if open hole completion

Cimentation :

To surface or partial (stage cementation if necessary)

Well Architecture

CASING DESIGN


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CASING DESIGN

Internal Pressure

Nothing (empty well)

Gas

Mud weight

Cement

External Pressure

Water

Mud weight

Cement

Formation

The cement isolation is usually ignored,

except during the cementing operations,

> the fluid outside the casing is the mud

of the previous phase.

Well Architecture

CASING DESIGN


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CASING DESIGN

While drilling then producing the well

a casing is submitted to various constraints :

While drilling the next phase

While being cemented

During the production phase (production casing)

The coming calculations will take care of these different conditions.

Well Architecture

CASING DESIGN


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CASING DESIGN

Collapse Criteria

Collapse may occur as a result of:

an increase of the external pressure, a decrease of the internal pressure,

a combination of both.

Various operations may lead to collapse :

1) Partial or full Evacuation (mud losses)

2) Air, Foam, Aerated Mud, Underbalanced Drilling

3) Cementing operations Floated Casing while running

4) Cementing operations

5) Drill Stem Testing6) Artificial Lift

Well Architecture

CASING DESIGN


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CASING DESIGN

Collapse Criteria

1a Partial Evacuation.

Apply for all Casings.

For Exploration Wells, the weakest zone will be taken at the final depth of the actual drilling

phase and the gradient of the losses as the water gradient.

Internal Pressure: The casing is empty down to the fluid level, the evacuation level will be

calculated in order to balance the weakest zone with the actual drilling mud weight.

1b Full Evacuation.

Production casing only. Full Evacuation is considered for Exploration and Development Wells.

Internal Pressure: The casing is empty.

2 Air, Foam, Aerated Mud, Underbalanced Drilling.

Full Evacuation must be considered for Exploration and Development Wells where these

techniques are planned.

Internal Pressure: The casing is considered as empty.

Well Architecture

CASING DESIGN


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CASING DESIGN

Collapse Criteria

3 Floated Casing While Running In Hole.

Apply for all Floated Casings.

Internal Pressure: The casing is empty down to the fluid level. The remaining fluid insidethe casing is the mud of the drilling phase.

4 Cementing Operations

Apply for all cemented Conductor and deep Surface Casings.

External Pressure: The fluid outside the casing is the cement slurry up to the top of cement andthe mud of the drilling phase up to the surface.

Internal Pressure: The fluid inside the casing is the displacement mud.

5 Drill Stem Testing

This case applies to both Production and Drill Stem Testing casings.

Internal Pressure: Casing empty from the casing shoe to the production packer.

Casing full of packer fluid (Production) or mud (DST) above the packer.

6 Artificial Lift

Development Wells only.

Internal Pressure: The casing pressure profile is calculated according to the artificial lift scenario.

Well Architecture

CASING DESIGN


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Collapse Pressure

Casing Collapse lines

Internal

pressure

Collapse

pressure

External

Pressure

Top

cement

Displacement

mud

Depth

Pressure

Casing cementation

Well Architecture

CASING DESIGN


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Collapse Pressure

Drilling

Mud

Fluid

level

Pressure

Depth

Casing Collapse lines

Internal

pressure

Collapse

pressure

External

Pressure

Partial losses

Well Architecture

CASING DESIGN


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Burst Criteria

Burst may occur as a result of:

an increase of the internal pressure, a decrease of the external pressure,

a combination of both.

Various conditions may lead to burst :

1. Oil & Gas Kick

2. Well full of Gas

3. Pressure Integrity and leak tests while drilling

4. Surface tubing leak during testing and production operations

5. Surface tubing leak in water & gas injection wells

6. Artificial Lift

7. Bullheading.

Well Architecture

CASING DESIGN


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Burst Criteria

1 - Oil & Gas Kick.

Apply for Surface and Intermediate Casings in Appraisal and Development Wells when Oil &

Gas kick are possible.

External Pressure: The fluid outside the casing is the mud of the previous drilling phase.

Internal Pressure: For oil, the resulting internal pressure profile will be a single phase

reservoir oil gradient from bottom hole to a point in the well at which local

crude saturation pressure is reached (bubble point), and a gas gradient

from this point to the surface.

2 - Well Full Of Gas

Apply to all Surface and Intermediate Casings in Exploration wells and Appraisal &

Development gas wells.


Internal Pressure: The fluid is gas (CH4) - gradient 0.1 psi/ft / 0.7 sgThe Bottom Hole Pressure is the anticipated reservoir pressure.

The pressure profile is a straight line.

Well Architecture

CASING DESIGN


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Burst Criteria

3 - Pressure integrity tests and Leak tests while drilling

Apply to all Casings.


Internal Pressure: The internal pressure gradient is the actual mud gradient added

of the testing pressure.

4 - Surface Tubing Leak During Testing & Production Operations

This case considers a Test/Production tubing leak at the top of the well.

The Wellhead shut-in pressure is supposed to be transmitted to the tubing-casing annulus.

Apply to Production Casings in Development Wells, and Delineation wells planned for a

possible later recovery.

External Pressure: The fluid outside the casing is clear water.

Internal Pressure: The internal pressure gradient is the packer fluid gradient incremented by

the wellhead shut-in pressure.

Well Architecture

CASING DESIGN


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Burst Criteria

5 - Surface Tubing Leak In Water & Gas Injection Wells

To apply for all Production Casings and Water & Gas Injection Wells.


Internal Pressure: The internal pressure gradient is the packer fluid gradient incremented by

the maximum anticipated Injection Pressure

6 - Artificial Lift

To apply to all Production Casings when Artificial Lift is planned.


Internal Pressure: The internal pressure is the maximum anticipated pressure that can

develop in the worst-case scenario (equipment failure).

7 - Bullheading

To apply for all Casings when Bullheading is the only way to kill the well.


Internal Pressure: The internal gradient is the actual mud gradient plus a margin of 2000 psi.

Well Architecture

CASING DESIGN


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Burst Pressure

Pressure

Depth Casing Burst lines

Internal

pressure

Burstpressure

External

Pressure

Reservoir

pressure

Well Head

pressure

Drilling

Mud

Top of

buble

Gas

Gas Invasion

Well Architecture

CASING DESIGN


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Burst Pressure

Pressure


Internal

pressure

Burstpressure

External

Pressure

Reservoir

pressure

Well Head

pressure

Gas

Gas Invasion(Well full of gas)

Well Architecture

CASING DESIGN


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Burst Pressure

Pressure


Internal

pressure

Burstpressure

External

Pressure

Reservoir

pressure

Well Head

pressure

Gas

Gas Invasion(Well full of gas)

Well Architecture

CASING DESIGN


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Triaxial Load capacity diagram (Von Mises diagram)

The triaxial load Capacity diagram provides a visual determination

of the casing string design adequacy

by both API and equivalent triaxial-stress design factors.

The triaxial load capacity diagram is a representation of

the von Mises equivalent (VME) triaxial-stress intensity

in relation to axial force and either internal or external pressure.

Well Architecture

CASING DESIGN


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Well Architecture

CASING DESIGN


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Triaxial Load capacity diagram (Von Mises diagram)

Tri Axial Load

(Without Safety Coefficients)

Tri Axial Load

(With Safety Coefficients)

Collapse

Compression

Burst

API operating window

(including Safety

Coefficients)

Traction

Well Architecture

CASING DESIGN


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Safety Factors

Conventional Design Factors

API uniaxial Loads

Burst 1.10

Collapse 1.00

Tension 1.30

Compression 1.00

Triaxial Analysis Von Mises Combined Loads 1.25

Well Architecture

Onshore Drilling Sequence


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It starts

with civil works

to build a platform,

in particular

the concrete base

to support the rig

and a cellar

where the well begins.

Well Architecture

Drilling Drilling Drilling Drilling DrillingConductor Surface Intermediate Production Production


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Onshore Drilling Sequence

Drilling

30

Drilling

1712

Drilling

1214

Drilling

812

Drilling

6Pipe

20

casing

1338

casing

95/8

casing

7

liner

41/2

1 pouce = 25,4 mm

1 pied = 0,3048 m

Lengths are measured in meters or feet

Diameters are measured in mm or inches

Well Architecture


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CASINGS, WELL HEAD & BLOW OUT PREVENTER

Well Architecture


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PRODUCTION WELL HEAD (Christmas tree)

Well Architecture

Drilling Programme


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Estimation Pression de pore

& Gradient de fracturation

(Extrait dun programme de forage)

Well Architecture


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Well Architecture


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Well Architecture

Programme de forage


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Well Architecture

Programme de forage


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well architecture rge 2008 jp szezuka

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