11 comp ferrari giuseppe stage master 2009-2010

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Subsea dual completions: State of the art, benefits and risks

Author: Giuseppe Ferrari

San Donato Milanese 20-21 October 2010

Master in Petroleum Engineering 2009-2010

2

Subsea dual completions: State of the art, benefits and risks.


Author

Ing. Giuseppe Ferrari

Division Exploration & Production

Dept. COMP/PERF

Company Tutors

Ing. Stefano Di Vincenzo

Ing. Gianfederico Citi

University Tutor

Prof. Ing. Francesca Verga

Master in Petroleum Engineering 2009-2010

3

Project Scope 1

State of Art Subsea Completion 2

Eni applications – Camilla 2 3

Risk Analysis 4

Conclusions 5

Summary

4

Project Scope

Dual Subsea Completion State of Art – analyze existing case

history from all main subsea vendors.

The Scope of Work of this thesis is summarized by

following points:

Prons and Cons of Dual subsea completion, compared with

standard single subsea completion.

Camilla 2 – Eni case history and close out post job report

analysis.

Risk analysis and Risk evaluation of Camilla 2 activity.

5

Project Scope 1



Risk Analysis 4

Conclusions 5

Summary

7

RIG

Drilling Ship (dynamic position)

Semi submersible (moored)

PRODUCTION

Floating production

On-shore and land site production

facilities

LANDING STRING

Hydraulic

Electro-hydraulic

X-TREE

Vertical design

Horizontal design

State of Art Subsea Completion

8

Subsea wells

All wells completed with subsea facilities

Deep Water Completion

(500 m < water depth < 1,500 m)

Ultra Deep Water Completion

(1,500 m < water depth)

Multilayers Reservoir

(more than two zones completed)

• Simultaneus production from all completed zones


9

There are three different completion options available on

the market, applicable to subsea fields:

Single string completion

Dual string completion

Intelligent well completion (IWC)


WD IV-ICV Infinitely Variable Choke size 3 1/2"

WD HF1 Retrievable Packer w/multi Feedthru

Tbg Retrievable Safety Valve size 3 1/2"

WD Flat Pack Umbilical with 3 Hydr.Lines

Size 7" x 3 1/2"

3-1/2" Tubing

7" 23-26 lb/ft Casing

1/4" Safety Valve Control Line

Crossover 3 1/2" x 2 7/8"

Locator with Moulded Seal Units

3-1/2" Tubing

Gravel Pack Screen on 4" Base Pipe

Moulded Seal Unit size 3.25"

Permanent Type Seal Bore Packer

Pup Joint

Polished Bore size 3.25"

Gravel Pack Packer with 3.25" Seal Bore

Gravel Pack Closing Sleeve

WD HV-1 Shrouded ON-OFF Type Choke

Wireline Plug

With Accu-Pulse

2-3/8" FJ Tubing

For 3.25" Seal Bore

Size 2 7/8"

Gravel Pack Screen on 4" Base Pipe

Gravel Pack Packer with 3.25" Seal Bore

Gravel Pack Closing Sleeve

Locator with Moulded Seal UnitsFor 3.25" Seal Bore

10

Factors that drive the decision to use a vertical tree:

Financial driver is “life of field OPEX”

Lower drive wells (smaller bore)

Simple reservoirs or low frequency of tubing retrieval workovers

High pressure – difficult well control issues

Pre owned installation tooling package (open water, completion riser)

Trend, gas wells, short life (little or no maintenance), well pressure

greater than 10 000 psi

A number of factors must be considered when deciding whether

to use a horizontal or vertical Xmas tree and these are described

below. However the otpimum subsea Xmas tree configuration

will be driven by reservoir requirements:

Factors that drive the decision to use a horizontal tree:

Financial driver is installed CAPEX

High drive wells or multilaterals (have need for large bore)

Complex reservoirs or frequent W/O requiring TBG retrieval

ESP or artificial lift technology

Bacth drilling/completion and/or requirements for drill thru systems

Little or no pre-owned installation tooling

Trend:oil wells, high maintenance or wells needing recompilation, well

pressure less then 10 000 psi


11

Horizontal Trees

Advantages Disadvantages

Suitable for large bore gas wells Requires an additional BOP trip

Can be installed on completions

wellhead

Requires a SSTT and landing

string

Reduced installation tooling

requirements

BOP may require modifications to

accommodate IWOC's umbilical

Uses rig riser system Higher bending loads on the

wellhead system

Simplified rig interfaces Potential leak paths below the BOP

Suitable for smart well technology Well must be plugged prior to

removing the tree

Allows workover without pulling

tree or disconnecting flowlines

Some concern with wireline plugs

for vertical barriers

Flow base typically not required Longer emergency disconnect time

Flexibility of design to accomodate

natural flow, gas lift, water injection

and ESP

Cannot pull tree independent of the

completion

Horizontal and Vertical X-Tree advantages and disadvantages


Vertical Trees

Advantages Disadvantages

One less BOP trip (Drill thru to

completion) tubing hanger

landed in the wellhead (or

tubing head)

May require BOP modification

for TH orientation mechanism

Allows intervention without a rig Requires leas impression tool

run to verify TH space out

Reduced wellhead loading Need more rig deck space to

accommodate additional tooling

and riser

Metal sealing gate valves for

environmental barriers, not field

installed like wire line plugs

Rig needs to handle more

tooling

Allow monitoring of all down

hole functions as standard

Additional wellhead casing

hanger required

Tubing intervention simpler as

no wire line plugs need to be

retrieved

Tubing hanger seals in the

casing that could be damaged

during drilling operations

Installed CAPEX considered to

be lower the horizontal tree

Need to remove the tree for

tubing work over

12


13

It is used with the horizontal xmas

tree, it accomodates the crown

plug. Some suppliers may replace

the internal tree cap with a longer

tubing hanger.


INTERNAL TREE CAP

2° Environmental Barrier

Metal to metal seal with X-Tree

5” Wireline Crown Plug

14


15

Used with the horizontal xmas tree, it is installed wire

line in the internal tree cap and in the tubing hanger

CROWN PLUG

Bore closures for both Tubing Hanger & ITC

10 000 psi working pressure

Primary Seal → Metal - to - Metal SSD Seal

Secondary Seal → Non - Elastomeric packing set

Pressure Set


or alternatively both in

the tubing hanger if the

supplier does not use

the internal tree cap

16


17


TUBING HANGER

HT - SG Seal

- Rated to 15 000 psi

- Above & below production/injection Bore

5” Wireline Crown Plug

downhole control lines

downhole control line for SCSSV

downhole control line for downhole smart completion

spare hydraulic line

electrical lines

Wet-mate electrical connector

Hanger premium thread

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DUAL BORE TUBING HANGER

Production Bore

Annulus Bore

Thread for tubing

Plugs

Thread for landing string

Control lines

Orienting pin

19

Dual Subsea completion – WW case history

FMC: one application for Chevron in UK North Sea in 1990.

Cameron: two applications for ENI in the Adriatic Sea, Elena 1 in 1989 and Camilla 2 in 2000.

Vetco: one application for Shell UK in Cormorant Field (UK North Sea) in 1982.

Aker: NO applications.


20

Project Scope 1



Risk Analysis 4

Conclusions 5

Summary

21

Eni applications - Camilla 2

The well location

22

Short String

Long String


Reservoir profile and intervals perforated

23


PTR = 23,6 mt on water level

Water Depth = 85 mt

Csg 30” @169 mt TVD

Csg 13”3/8 @344 mt TVD

Liner head 7” @955 mt TVD

Csg 9”5/8 @1104 mt TVD

Liner 7” @1477 mt TVD

Well Schematic and casing profile

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Dual string 2” 3/8 + Gravel Pack Assy (lev. 1 e 2+3)

lev. 1

lev. 2+3


25

Subsea Wellhead Tubing Head Spool


26

Subsea Wellhead Subsea X-Tree


27

The Rig used to drill and complete the well is a

Semisubmersible moored type named Zagreb 1,

property of Crosco International LTD.


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OPERATION BUDGET FINAL BALANCE Δ % % of total

RIH completion 42,0 32,0 -23,8% 4,5%

Well Test/Clean up/PT data measurement 71,0 154,0 116,9% 21,4%

Scraper 6,5 4,0 -38,5% 0,6%

TCP guns 30,0 23,0 -23,3% 3,2%

Logs 6,0 5,5 -8,3% 0,8%

X-Tree installation 36,5 80,0 119,2% 11,1%

BOP Installation/testing 4,0

Killing/Static Well Control/Circulation/Brine 3,0 2,5 -16,7% 0,3%

W.L. Operations 21,5 16,0 -25,6% 2,2%

TTBP/PKR Plug installation 1,0 2,5 150,0% 0,3%

Csg Clean up/Filtering 5,0 16,5 230,0% 2,3%

BOP Installation/Disinstallation/Test 79,0 65,0 -17,7% 9,0%

Gravel Pack/Frac Pack 127,0 80,5 -36,6% 11,2%

Well securing operations 13,5 10,5 -22,2% 1,5%

Other well operations 147,0 128,0 -12,9% 17,8%

Cement mill and cleaning 20,0 9,5 -52,5% 1,3%

Divers operations 10,0 8,5 -15,0% 1,2%

ROV operations 2,0

Log correlations 12,0 3,5 -70,8% 0,5%

Not provided operations 0,0 20,0 2,8%

Maintenances 0,0 4,5 0,6%

Down times 0,0 6,5 0,9%

Negative hydraulic tests 0,0 2,0 0,3%

Breakdowns 0,0 5,0 0,7%

Waitings 0,0 39,5 5,5%

TOTAL (Hours) 637,0 719,0 12,9%

TOTAL (Days) 26,5 30,0

The completion operations time analysis


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Project Scope 1



Risk Analysis 4

Conclusions 5

Summary

31

The Risk Analysis was developed with these hipotesys:

The completion operations were deducted from the Camilla 2

completion because it is the most recent well completed with dual

string by Eni.

There are very few subsea wells with dual string completion, and a

lot of them are old, so it is difficult to find the informations about the

operations and the related problems. Therefore the values of

Probability and Impact for the operations were found out with the

help of expertises.

The analysis is qualitative and based on STAP-P-1-N-20913:

“Project Risk Management for Drilling, Completion and production

Optimization Activities”.

Risk Analysis

32

Risk Analysis

Completion execution phases:

Engineering

&

Procurement

Installation Operations &

Maintenance Decommissioning

The Risk analysis was developed for Engineering &

Procurement and Installation for the Single String and the

Dual String with the mitigating actions for a risk reduction

33

N

Engineering and Procurement


Original Risk

Mitigations Residual Risk

P I RL P I RL

Environment

Weather and

sea conditions

1) Global Riser Analysis ---> simulation of RIH and installation of Landing String

and Tbg string: poor data and uncertainties on the RIG, for the

availability and for the RIG choice

B 2 M

this could affect the real functioning system for the

landing string and for drilling riser, so simulation could

be aborted and not considered during the operations

B 3 M

Rig

Availability 2) Market conditions: availability of the rig and costs: depend by the area of

working, in case of mediterranean sea floating RIG are very poor, other

areas permits to have RIG availability with different daily rate

D 4 M

plan activity where it is possible with the right completion

schematic and based also on RIG availability on the

markey

D 5 L

3) Mobilization on time: time to MOB/DEMOB and the travel C 4 M

plan the activity with right time in order to avoid any delay C 5 L

Performance 4) Availability of specific equipment: Rig set for drilling activities

C 4 M

doublecheck before to commence the moving or before to

sign the contract the availability of the completion

tools on board, finalize right contract for completion

activity (services)

C 5 L

5) Reliability (QA, HSE and maintenance)

B 4 L --- B 4 L

6) Experienced operating team

C 3 M --- C 3 M

Completion

7) Availability of the specific equipment rarely used by the oil companies:

manufacturing line set for standard equipments - B 2 M

plan the activity with right time in order to avoid any delay

or consider the activity without Rig window availability

but always on the market

B 3 M

8) Time to engineering: it takes more time because it is uncommon, personnel

not skilled and new design B 3 M

possibility to choose all standard equipments on the

market and modify the completion goals based on the

market proposal

B 5 L

9) Delivery & manufacturing: special items, like TH for dual string, are required

and they have to be manufactured ad hoc B 4 L

--- B 4 L

10) Test and qualification (no common): procedure of testing and qualification

are not defined by ISO and it could be written and agreed B 2 M

action by company to control and check procedure of test B 4 L

11) Orizontal vs vertical X-Tree ---> it is suggested to use horizontal XT where it

is necessary to re-entry instead in shallow water it is possible to go with

vertical XT. where few hydraulic lines and electrical lines are requested it

is suggested to avoid vertical XT

B 2 M Evaluation prons and cons choose a horizontal vs vertical

X-Tree fitting with dual subsea completion B 3 M

Risk Analysis

34

N

Installation


Original Risk

Mitigations Residual Risk

P I RL P I RL

Environment

Weather and sea

conditions

12) Strong heave ---> need of motion compensator to counter the

movement C 3 M

squall not considered, wave abnormal, strong wind more

than 45 kn; possibility of investigation on environment

conditions historycally

C 4 M

Rig

Availability 13) Truster functioning (DP) ---> it keeps the rig in the right position B 2 M --- B 2 M

Performance 14) Motion compensator ---> if it does not work, it can append that the rig

must stop the operations C 3 M --- C 3 M

Completion

15) Staff: generally the staff does not have the skills in this area, so special

training and team building is requested C 2 H

organize few meeting between contractor and company in

order to standardize the procedure C 4 M

16) Space on deck rig number of reels: possibility to have few numers of

reels C 4 M

avoid to run control lines more than SCSSV inside of

downhole completion package C 5 L

17) Running TH with landing string: dedicated landing string and umbilical

for this operation C 1 H

define with landing string supplier and subsea vendor the

best design and optimize with market availability. Optimize

the plan in order to reduce delivery C 2 H

18) Shearability dual string completion in BOP: impossibility to shear two

strings inside of BOP C 1 H

verify with RIG contractor possibility and new design C 3 M

19) Landing dual string completion: planning procedures, new operations

C 2 H

agreed all personnel on procedures, operations meeting

before to begin, perform during the day, to have all SPV on

the rig floor

C 3 M

20) Orientation TH: it is the most difficult operation and it needs to be done

with the motion compensator working C 1 H

as point above C 2 H

21) X-Tree installation: verify the procedures with contractors

C 2 H analyze with subsea vendor best procedures and analyze

methodology C 3 M

22) Retrieving Wire Line Plugs/clean up/Well Test C 4 M

--- C 4 M

23) Cap/protective frame installation C 5 L

--- C 5 L

Risk Analysis

35

N

Engineering and Procurement


Original Risk

Mitigations

Residual Risk

P I RL P I RL

Environment

Weather and sea

conditions

1) Global Riser Analysis ---> simulation of RIH and installation of Landing String

and Tbg string: poor data and uncertainties on the RIG, for the

availability and for the RIG choice B 2 M

this could affect the real functioning system for the

landing string and for drilling riser, so simulation

could be aborted and not considered during the

operations

B 3 M

Rig

Availability 2) Market conditions: availability of the rig and costs: depend by the area of

working, in case of mediterranean sea floating RIG are very poor, other

areas permits to have RIG availability with different daily rate

D 4 M

plan activity where it is possible with the right

completion schematic and based also on RIG

availability on the markey

D 5 L

3) Mobilization on time: time to MOB/DEMOB and the travel

C 4 M plan the activity with right time in order to avoid any

delay C 5 L

Performance 4) Availability of specific equipment: Rig set for drilling activities

C 4 M

doublecheck before to commence the moving or

before to sign the contract the availability of the

completion tools on board, finalize right contract

for completion activity (services)

C 5 L

5) Reliability (QA, HSE and maintenance)

B 4 L --- B 4 L

6) Experienced operating team

B 4 L --- B 4 L

Completion

7) Availability on the market

B 4 L Take standard equipment on the market

B 5 L

8) Time to engineering B 5 L

--- B 5 L

9) Common test and qualification B 4 L

--- B 4 L

10) Horizontal vs vertical X-Tree ---> it is suggested to use horizontal XT where

it is necessary to re-entry instead in shallow water it is possible to go with

vertical XT. where few hydraulic lines and electrical lines are requested it

is suggested to avoid vertical XT

B 2 M

Evaluation prons and cons choose a horizontal vs

vertical X-Tree fitting with dual subsea

completion

B 3 M

Risk Analysis

36

N

Installation


Original Risk

Mitigations

Residual Risk

P I RL P I RL

Environment

Weather and

sea conditions

11) Strong heave ---> need of motion compensator to counter the

movement C 3 M

squall not considered, wave abnormal, strong wind more than 45

kn; possibility of investigation on environment conditions

historycally

C 4 M

Rig

Availability 12) Truster functioning (DP) ---> it keeps the rig in the right

position B 2 M --- B 2 M

Performance 13) Motion compensator ---> if it does not work, it can append

that the rig must stop the operations C 3 M --- C 3 M

Completion

14) Staff skilled for subsea operations

B 4 L ---

B 4 L

15) Space on deck rig number of reels: possibility to have few

numers of reels C 4 M

avoid to run control lines more than SCSSV inside of downhole

completion package C 5 L

16) Running TH with landing string

D 4 M

define with landing string supplier and subsea vendor the best

design and optimize with market availability. Optimize the plan

in order to reduce delivery D 5 L

17) Shearability completion string in BOP

C 4 M verify Rig BOP bullettin (shear sub)

C 5 L

18) Landing completion string: planning procedures

C 3 M agreed all personnel on procedures, operations meeting before to

begin, perform during the day, to have all SPV on the rig floor C 4 M

19) X-Tree installation: verify the procedures with contractors

D 4 M analyze with subsea vendor best procedures and analyze

methodology D 5 L

20) Retrieving Wire Line Plugs/clean up/Well Test

C 4 M ---

C 4 M

21) Cap/protective frame installation

C 5 L ---

C 5 L

Risk Analysis

37

The following matrix shows the differences between the

risk associated to the single string and the dual string

completion

Installation operations

Risk Analysis

38

The following matrix shows the risk reduction due to the

mitigating actions taken

17 – Running Tubing Hanger with landing string

20 – Tubing Hanger orientation

Risk Analysis

39

Project Scope 1



Risk Analysis 4

Conclusions 5

Summary

40

The following conclusions could be carried out:

Conclusions

A pre-enquiry with all major subsea vendors shows a poor case

history of dual subsea completion with SSXT dual bore

Single completion is strongly preferred to dual in subsea

completion operations

Actual market does not propose standard equipments for dual

subsea completion and SSXT with dual bore. This condition affects

the choice of subsea dual completion development

Risk analysis conducted on previous experience of ENI, shows

major criticalities during operations compared with a single

completion

Vertical XT is preferred to horizontal type to couple to dual subsea

completion, but with all constrains of subsea applications

41

Acknowledgements

I would thank Eni E&P Division Management for

permission to present this work and related results

and COMP colleagues for the technical support and

needed assistance.


11 comp ferrari giuseppe stage master 2009-2010

Documents

daily rate

experienced

wire line

2010subsea

real functioning

moulded seal

environment

internal tree