Open vs Cased Hole Sand Control Completion Selection Rev1

Open vs Cased Hole Sandface Technique Selection

Cased Vs Open Hole Open Hole

Cased Hole

Perforations Liner/Casing

Sand Control Completion Types Cased Hole (50 to 250 ft screen per well)

Frac-pack

Gravel Pack

Open Hole (1000 to 3000+ ft screen per well)

Stand Alone Screen

Gravel Pack

(Including ICD)

(Alpha Beta and APS)

ESS

Completion Selection Drivers • • • • •

Efficiency – lowering cost Reliability Longevity Risk mitigation Completion performance REVENUE

CAPEX + OPEX + RISKEX

PROFIT

? BG

Technical Considerations • • • • • •

Production rate/kh Zonal isolation Wellbore stability Stresses – can I fracture Depth Interval length

BG

Open Hole – when When • High rate/kh wells • Longer interval length

Limitations/Risks • Wellbore stability • Multizone wells • Zonal isolation

Benefits • Higher productivity – low skin • Lower well cost

BG

Cased Hole – When When • Multizone wells • Deeper wells • Full zonal isolation • Wellbore stability

Limitations/Risks • Perforations are choke for high rate wells (especially gas) • Interval length limited to < +/400ft (TVD), unless stacked

Benefits • Reliable

BG

Productivity Driver for Open Holes

Oilfield Review Summer 2001

Transmissibility, 1000 md-ft/cp BG

Welling Criteria – SPE 39475 Based on modeling • For oil wells: Fracpack if Kres < 900 mD OHGP if Kres > 900 mD • For gas wells: Q < 200 Mscf/d Fracpack if Kres < 300 mD HRWP if Kres > 300 mD Q > 200 Mscf/d F&P if Kres < 200 mD HRWP if Kres > 200 mD Q > 500 Mscf/d F&P if Kres < 150 mD HRWP if Kres > 150 mD OHGP if Kres > 600 mD BG

Horizontal Open Hole • • • • • • •

Increase reservoir contact Avoid coning Reduce flux rates for thin pays Minimize compaction issues Improve sweep Stitch compartmentalized reservoirs Reduce risk of sand production

* Open hole completions increase operational complexity and pose more completion risk BG

Open Hole Completion Type Selection - Key Parameters • • • • • • • • •

Rock strength properties – UCS, in-situ stresses Formation Particle Size Distribution (PSD) Drilling mud environment Is the formation homogenous or heterogeneous Are there reactive shales Reservoir – fracture pressure window Zonal isolation Sand production at the onset of depletion Is it a high risk environment – subsea BG

Particle Size Distribution (PSD) Cumulative Log Diagram Sample B Well Sorted

Saucier Sizing 20/40

40/60

100% 90% D50

Cum. % by Weight

80% 70% 60% 50%

Sample A Poorly Sorted

40% 30%

0.006

20%

0.017

10% 0% 0.1000

0.0100

0.003

0.0010

0.00021

0.0001

Grain Diameter (inches) D40 0.006 = = 29 D90 0.00021

D40 0.003 = =3 D90 0.001

Sample A BG

Sample B

Water Packing or Shunt Packing (SPE 85504) High Risk Environments
Deepwater
Low Net to Gross w/Reactive Shales
Wells drilled with S/OB-RDFs – thin filtercake
Out of gauge hole sections
Subsea wells (rathole size and length below last casing point)
Low or unknown Frac gradient
Inflatable packers required for compartmentalisation/zonal isolation
Simultaneous GP and Cleanup preferred (particularly Injectors)
OH Fracing (injectors)

BG

Based On Field Experience (Bennett et al., BP)

BG

Fracpack vs HRWP HRWP when • Marginal economics • Pressure limitations in the near wellbore area – Probability of parting casing/liner top

• Close proximity to water • HHP limitations

BG

Gravelpack

CH FP w/screens

OH FP w/screens

CH Frac no screens

OH Frac no screens

Best Completions Based On Production

Perforations

Completion Options

Sand Control Borehole Stability

Poor 1

Sustained Production

Fair 2

Zonal Isolation

Good 3

Rig Time Savings Execution Logistics 10

BG

9

11

11

13

12

Sand Control Geographic Distribution - Completion Type Sand Prone Reservoirs

OH Water Pack SAS North Sea Alaska

CH Fracpack

OH Gravel Pack

Eastern Canada

Baku

OH Water Pack SAS

Italy Egypt

GoM

Saudi Arabia South China Sea

Venezuela and Trinidad

OH Gravel Pack APS Water Pack

Nigeria India

CH FP Angola OH GP APS Water Pack Brazil

OH Water Pack CH Fracpack

BG

Australia

Questions?

BG