Dual Casing Running for deep water spud in

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Dual Casing Running

for deep water spud in

Dual Casing Running for deep water spud in

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• Focusing the issue

• Deep water operation: Riserless top hole section

• Deep Water Dual Casing: MAIN PHASES

OPTIONS

REQUIRMENTS

• Applications

• Conclusions

Presentation


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Deep water activities:• extreme environment

• heavy load conditions with unconsolidated sea bed• high daily spread rate

The improvement of operations with the aim to increase the efficiency can produce a time

reduction and as consequence a

cost saving


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Conventional technique

• Drill 36” holeDrill 36” hole• Run and cement Run and cement

30” CP30” CP• Drill 26” holeDrill 26” hole• Run and cement Run and cement

20” csg20” csg

Jetting &Drill-Ahead

• Jet 30” CP and Jet 30” CP and

drill 26” holedrill 26” hole• Run and cementRun and cement

20”csg20”csg


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Traditional techniques – CONSTRAINS:

• uncertainty about the formation to cross

• perfect verticality of WH and correct stick up

not granted

Deep Water Dual Casing


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Conventional technique

• Drill 36” holeDrill 36” hole• Run and cementRun and cement

30” CP30” CP• Drill 26” holeDrill 26” hole• Run and cementRun and cement

20” csg20” csg

Deep WaterDual Casing

Jetting &Drill-Ahead

• Drill 23” x 36” Drill 23” x 36”

hole with HO in hole with HO in

tandemtandem• Run and Run and

cement 30” CP cement 30” CP

and 20” csgand 20” csg

• Jet 30” CP and Jet 30” CP and

drill 26”or 23”drill 26”or 23”• Run and cementRun and cement

20”csg20”csg

• 2 drilling phases2 drilling phases• 2 cementing jobs2 cementing jobs• 4 round trips4 round trips

• 1 jetting phase1 jetting phase• 1 drilling phase1 drilling phase• 1 cementing job1 cementing job• 2 round trips2 round trips

• 1 drilling phase1 drilling phase• 1 cementing job1 cementing job• 2 round trips2 round trips


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Drill23” or 17 1/2”

hole

No RotationNo Rotationby using straight by using straight

hole drilling device hole drilling device and motorand motor


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Start RotationStart Rotationforfor

42” or 36” Hole42” or 36” Hole

Drill23” or 17 1/2”

hole


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The hole inclination approximately 0° (zero degree)

Drill 23”or 17 1/2” hole+ 42” or 36” hole

With RotationWith Rotationforfor

36”/42” Hole36”/42” Hole


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End of

23” or 17-1/2” hole

+ 42” or 36” hole

POOH


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36” or 42” hole+

23” or 17 1/2” hole


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Ready to Run:

Combination

36” or 30” C.P. +

20” csg or

20”+13 3/8” Tapered csg


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Shown with mud mat & ball valve

MS 700 Wellhead Systems Guidelineless Type Drilling System without Guide structure

Hydrate Gas Seals

Low-pressure Housing Lowered into Mud Mat

Cement Port


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DA COMPLETARE

Inner string DP 5”

Casing 13 3/8”

Conductor pipe 30”

Casing 20”

36” Hole

Housing 30”

Housing 18” 3/4

Mud Mat

CART 18” 3/4

17 1/2” Hole

• Standard cementStandard cement• DeepCRETEDeepCRETE• Foam cementFoam cement


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Case History

ENI Angola

1 Job: 30”x20”x13 3/8” Casing

2 Jobs: 30”x20” Casing


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ANGOLA OFFSHORE – CASE HISTORY# 1: Standard cement

WD: 1300 m; Sea-bed temperature: 4 °CShallow water risk: no

Cement job: 30” C.P.x 20” x 13 3/8” tapered combined string

Lead slurry: 1.44sg (12ppg) LiteFIL Tail slurry: 1.90sg (15.9ppg)

Displacement: no cement returns at seabedWOC: 13 hrs Slack-off: casing string unstableWOC: additional 6 hrsSlack-off: OKTop job: cement job performed to ensure cement to sea bed


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ANGOLA OFFSHORE – CASE HISTORY

# 2: DeepCRETE Cement

WD: 500 m; Sea-bed temperature: 6 °CShallow water risk: yes

Cement job: 30” C.P. x 20” casingLead slurry: 1.20sg (10ppg) DeepCRETE with D500 GASBLOKTail slurry: 1.90sg (15.9ppg) with D500 GASBLOKDisplacement: returns at seabedWOC: 15 hrs Slack-off: casing string 1 cm “sink”WOC: additional 3 hrsSlack-off: OKTop job: no top job performed


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ANGOLA OFFSHORE – CASE HISTORY# 3: Foam Cement

WD: 1070 m; Sea-bed temperature: 5 °CShallow water risk: no

Cement job: 30” C.P. x 20” casing

Lead slurry: 1.25sg (10.4ppg) Foam cementTail slurry: 1.90sg (15.9ppg)Displacement: partial returns at seabedWOC: 15 hrs Slack-off: OKTop job: no top job performed


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Inner string DP 5”

Casing 13 3/8”

Conductor pipe 30”

Casing 20”

17 1/2” Hole

36” Hole

Housing 30”

Housing 18” 3/4

CART 18” 3/4

Mud Mat

Wellhead cut and retrieved Annulus 20” - 30”


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3 different options:

• M/U C.P. and surf. csg during flat time and hang up them on Moon Pool trolley

• M/U C.P. during flat time but surface casing on line after drilling tapered hole

• M/U C.P. and surf. csg on line after drilling tapered hole


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• VDL to load spud in materials

• Motion compensator capability

• Moon pool trolley capacity > (C.P.+surface csg+inner string) weight w/S.F.

• Distance moon pool – sea bed > lenght of surface casing

Requirements for full application:


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If all requirements are NOT fully satisfied:

Partial time saving but all other advantages are exploited:

• no C.P. sinking can occur

• housing pre-fixed stick up and verticality near to 0° is granted

• applicability in all lithology types

• latch between LP and HPWH Housing performed at surface, ensuring mechanical structural integrity


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Dual Activity rig:


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- Drill 8 ½” P.H.

- M/U 36” C.P.

- Run BOP

- Drill 23”x42” hole

- Run BOP

- Run Dual csg string

- Run BOP

- Cementing op.


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Operating time during riserless phase (drilling pilot hole and running BOP not included)

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150

Conven

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Wells

Ho

urs

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500

1000

1500

2000

2500

3000

Me

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Hours WD [m] Drilled interval [m]

Mean 108 hrs

Mean 57 hrs


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Deep water Dual Casing, a patented technology, is the most efficiency alternative to conventional techniques.

Advantages:• Hole inclination approximately

0 deg

• Reduction of risk assessment in

C.P. setting for unknown lithology

• No subsidence events

• Top Cement Job feasibility

• LP HSG and HP HSG latch

performed at surface

• Time reduction

Constrain:• Water depth longer than surface

casing setting depth (Reduction of

system efficiency)

• Rig technical characteristics

• If shallow hazard phenomena

imposes the use of 26” intermediate

casing (36” LP HSG & CP)

Documents

Dual Casing Running for deep water spud in