Subsea well intervention: Learning from the past - planning for the future

Subsea well intervention; Learning from the past – planning for the future UTC 2010 Trond Inge Ramsnes

Beautiful but demanding

Optimising reservoir recovery from subsea fields
Increased fluid handling capacity
Reduced wellhead pressure
Integrated Operations
Identify
Drainage points
Well intervention needs and opportunities
Ambition : increase subsea recovery Cost effective drainage & well intervention

Cumulative wells – Statoil NCS 0 100 200 300 400 500 600 700 1980 1990 2000 2010 Dry trees Wet trees

Learning from the past – planning for the future RLWI Cat B TT riser 2 ⅞ ” CT
Platforms only to date
Spoolable connectors
Sweep cleanouts
TT Drill TTML
TTRD platforms and subsea
CTD (Gullfaks)
Safe & efficient operations
Full technical capability including MPD
Solid base for delivery of through tubing technology
Backup to RLWI
Cost efficient
Data collection
Light perforating
Light mechanical wireline
TTRD
CTD
CT/WL intervention
Maintain motherbore production
Access by-passed reserves
Gullfaks, Veslefrikk
2000 2002 2003 2004 2009 2013

Impact of well intervention – mature asset 0 2000 4000 6000 8000 10000 12000 14000 16000 18000 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Oil Sm 3 / D No activity Drill New Maintenance

Addressing challenges – realising opportunities Milling or high pressure jetting to remove scale Straddles or patches to repair tubing Wellbore cleanout, fill removal with long or reverse circulation Selective zonal isolation, mechanical or chemical Heavy duty fishing with simultaneous removal of fill Wellbore unloading with nitrogen Formation matrix or fracture stimulation Milling and underreaming to remove wellbore scale Perforating long sections Scale build-up in the upper completion Equipment problems SCSSV Access problems Restricted production Water influx Wellbore scaling Access problems Restricted production Formation damage (scale, fines, etc.) Restricted production “ Fishes” Access problems Restricted production Water holdup Wellbore sanding Access problems Restricted production Completion integrity issues

Category A RLWI Category B Full range intervention & TTD Category C Drilling and completion • Wireline / tractor only • Limited bha length • Full range of through tubing services • Limited live well through tubing services High pressure light weight riser (8 - 5/8 ” ) Low pressure marine riser (21 ” ) standard HP concentric riser and SSTT required for live well intervention

Cat B – fit for purpose concept Lightweight HP riser system (through tubing) Full DP or mooring assisted station keeping options Topside system sized for through tubing operations (2⅞” & 3 ½” drillpipe) Integrated high capacity coiled tubing package (2 ⅞” / 3 ½”) Full handling of live well returns Semi-submersible rig hull type

LRP/EDP stack on BOP carrier SBOP In rack-back area Key components in riser system

Operational Limitations
WSOG
Position reference
Propulsion
Riser system limitations
Wellhead limitations
Drift-off / drive-off
” Zero Moment Position”
RMS system used as advisory system for rig positioning
Fatigue monitoring / management

Experience with TT Riser System
Pilot operation with new system offshore
new equipment and procedures
stepwise and constrained progress.
Improve cleaning after milling and drilling operations.
No wear of the high pressure riser detected
RMS
High focus – used actively
Relatively nice weather – low utilization
High angles in Upper Flex Joint

Protecting Horizontal XT (HXT) – used on all pipe runs - Classification: Internal 2010-04-12 HORIZONTAL XMAS TREE PIGGY BACK WEAR SLEEVE TUBING HANGER NIPPLE PROTECTOR

Through Tubing Drilling (TTD) drilling through existing tubing (completion) Existing production tubing Production packer Whipstock Through Tubing Sidetrack Production from ’motherbore and new sidetrack simultaneously Reservoir SSD CHOKE

Operational experience Åsgard P-4 < 300 kSm3 < 100 kSm3 < 50 kSm3 Decreasing target volume Increasing target count & reserves Additional reserves Cat B enabled

P-4 AH Actual Drilled Wellpath – Geological Cross Section Not Ile 2 & 3 Ror Tilje 3 TVDMSL Tilje 1 & 2 Tilje 4, 5, 6 Ile 1 Garn 3 & 4 Garn 1 & 2 T1 T2 T3 T4 T5 Kick off 3871mMD Garn 3 P-4 H mother bore P-4 AH actual Drilled a world record of 1744m 5 ¾” TTRD sidetrack

Production P-4
Initial production
approx. 20 000 boe/d

Status Category B Services
3 Contractors carrying out FEED (Front End Engineering and Design) in the period March - September 2010;
Aker Oilfield Services
Helix WellOps
Saipem
Bid process ongoing – bid due mid October
An 8 years “Cat B Services Contract” will be awarded this year
Operations commencement Q3 2013

Subsea well intervention; Learning from the past – planning for the future Trond Inge Ramsnes Project Leader Well Intervention trira@statoil.com, tel: +47 51 99 00 00 www.statoil.com Thank you

Subsea well intervention: Learning from the past - planning for the future

by Statoil ASA

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