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GWF-1 Development DrillWell
Gary Nettleship Completion Engineer
4th September 2014
DRIMS#9711174
Disclaimer and important notice
2
This presentation contains forward looking statements that are subject to risk factors associated with oil and gas businesses. It is believed that the expectations reflected in these statements are reasonable but they may be affected by a variety of variables and changes in underlying assumptions which could cause actual results or trends to differ materially, including but not limited to: price fluctuations, actual demand, currency fluctuations, drilling and production results, reserve estimates, loss of market, industry competition, environmental risks, physical risks, legislative, fiscal and regulatory developments, economic and financial market conditions in various countries and regions, political risks, project delay or advancement, approvals and cost estimates. All references to dollars, cents or $ in this presentation are to Australian currency, unless otherwise stated. References to “Woodside” may be references to Woodside Petroleum Ltd. or its applicable subsidiaries.
Development Changes - NWS
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Previously: Platforms with multi-TCF* reservoirs Goodwyn, North Rankin and Perseus Now: Subsea tiebacks with smaller reservoirs 10’s to 100’s BCF**
Persephone to
NRA
GWF-1 to GWA 5 wells GWF-2
to GWA
Perseus Over
Goodwyn
Echo Yodel
* TCF is Trillion Standard Cubic Feet ** BCF is Billion Standard Cubic Feet
Overview of GWF-1 Subsea tieback to GWA
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Wells Two SMART dual zone Frac Pack wells Three SMART dual zone ESS* wells Subsea & Topsides 16” pipeline with CRA** lining Control umbilical from GWA platform Optical oil detection on GWA * ESS = Expandable Sand Screens ** CRA = Corrosion Resistant Alloy
GDA01
GDA02
Well Design Drivers
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Opportunity / Risk Impact Wells intersect multiple reservoirs
Increase reserves per well by producing multiple zones
Monitor un-produced zones for depletion
Some reservoirs have insufficient reserves to justify a well
Oil production reduces condensate value Shut off oil or water production zone
to produce gas from other zones Driver to use ‘smart’ completion
Water production exceeds production system capacity
High subsea well intervention costs
Transient sand production likely in high rate subsea gas well
Subsea well requires sand control Select conservative sand control method – Gravel pack
Limited core material for sand control selection
Smart* subsea well with multiple zones & sand control *Smart = Real time acquisition of pressure and temperature data and remote control of zonal flow
Greater Western Flank 1 Development
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Five subsea wells tied back to Goodwyn Platform via 16” pipeline Three work phases: 1. Drilled five wells in 2012 2. Complete GDA01 & GDA02 in 2013 3. Complete three Tidepole wells
GDA01 & GDA02: Two zone Frac Pack Two ‘S’ shaped wells Monitoring zone with cable-less gauges SMART completion
GDA01 & GDA02 Completion Schematic
Cure losses Clean up x 2 Perforate Lower Frac Pack Install GP Isolate completion Frac Pack
Cure losses Clean up x 2 Perforate Upper Frac Pack Install GP Isolate completion Frac Pack
Install Upper Completion - 2m depth uncertainty over 3200m - 60 hours control line termination - Ensuring flat pack is not damaged
Perforate WBCU Monitoring Cure losses Zone Install Install sump debris plug packer / gauges
12 planned trips in hole New technology 9-5/8” liner installed Small tubing & washpipe
Small debris intolerant components Frac Pack high KH KH = Permeability * Formation Height
Cable-less Gauge Complicated & high risk
HDFAV
2.94” Isolation
Ball Valve
GDA01 Installed dual zone cased hole Frac Pack completion Experienced challenges related to ‘S’ shaped well increasing torque and drag Successful installation of SMART upper completion Successful execution of lower V3 interval gravel pack Compromised gravel pack of upper V5 interval
GDA01 Outcome
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Models predict high KH can be fractured
Acetic Acid for clean up sub-optimal
V5 interval screened out early at 3ppg*
Insufficient proppant across top sand screen
or
Voids in the proppant pack
Gas production erodes exposed sand screen
* ppg = pounds per gallon
Compromised V5 Gravel pack likely cause:
Frac Pack Application & KH
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0
50,000
100,000
150,000
200,000
250,000
300,000
350,000
400,000
0 1000 2000 3000 4000 5000 6000
KH (m
D-f
t)
Permeability (mD)
Frac and Pack Analogues
Total Cameroon Analogue
GDA01 V5 interval looking to extend Frac Pack envelope
GDA02 V2 changed to High Rate Water Pack (HRWP) GDA02 V5 remained as Frac Pack
GDA01 V5
GDA02 V2
GDA02 V5
Permeability (mD)
KH (
mD
-ft)
Learning implemented for GDA02
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GDA02 Changes: Increased pump rate from 20 to 27 barrels per minute Pumped 15% HCl acid to clean up perforations – Injectivity increased Committed to gravel pack integrity ‘restress’ check on both zones V2 zone HRWP due to high KH V5 zone Frac Pack dependent on DataFrac, switch to HRWP if needed
Result: V2 successful execution of HRWP – 14,000 lb proppant placed V5 successful execution of Frac Pack – 39,000 lb proppant placed up to 6 ppg Restress showed proppant above sand screens for both zones
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Learning: Increase Development focus on D&C risk Examples Subsea reducing scope / risk by centralising wells at manifolds resulting in ‘S’ shaped wells Reservoir accessing more reserves with two zones versus single zone Accelerating D&C work to increase overall project value
Risk Balance Between Functions
Central Deviated
Central S-Shape
Single Zone
2-zone SMART
HRWP ESS
Subsea Well Constructability Risk
2-zone SMART
F&P
Distributed Vertical
GDA01
0
5
10 D&C
SS Res
Functional Complexity
(GDA)
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Key Learning:
Increased challenge with other functions to balance project risk
Preference for lower risk well types
Increased Front End Loading for new complex well designs
DEVELOPMENT EXAMPLE Previous concept: Three SMART dual zone CHGP* After concept challenge: One SMART dual zone CHGP Two single zone OHGP** * CHGP = Cased Hole Gravel Pack ** OHGP = Open Hole Gravel Pack
Subsea Well Constructability Risk 3 Wells
1 Well
2 Wells
Implementation for future projects
Central Deviated
Central S-Shape
Distributed Vertical
Single Zone
2-zone SMART
HRWP ESS
2-zone SMART
F&P
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