Open vs Cased Hole Sandface Technique Selection

Cased Hole Open Hole

Perforations

Cased Vs Open Hole

Liner/Casing

Gravel Pack

Cased Hole (50 to 250 ft screen per well)

Frac-pack

Sand Control Completion Types

Gravel Pack Frac-pack

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

ESSGravel Pack (Alpha Beta and APS)

Stand Alone Screen (Including ICD)

Completion Selection Drivers

Efficiency lowering cost

Reliability

Longevity

Risk mitigation

Completion performance

BG

Completion performance

REVENUEREVENUE RISKEXRISKEXOPEXOPEXCAPEXCAPEX + +

?PROFITPROFIT

Technical Considerations

Production rate/kh

Zonal isolation

Wellbore stability

Stresses can I fracture

BG

Depth

Interval length

Open Hole when

When

High rate/kh wells

Longer interval length

Limitations/Risks

Wellbore stability

Multizone wells

Zonal isolation

BG

Benefits

Higher productivity low skin

Lower well cost

Zonal isolation

Cased Hole When

When

Multizone wells

Deeper wells

Full zonal isolation

Limitations/Risks

Perforations are choke for high

rate wells (especially gas)

Interval length limited to < +/-

400ft (TVD), unless stacked

BG

Wellbore stability

Benefits

Reliable

400ft (TVD), unless stacked

Productivity Driver for Open Holes

Oilfield Review

Summer 2001

BG

Transmissibility, 1000 md-ft/cp

Welling Criteria SPE 39475

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

Based on modeling

BG

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

Horizontal Open Hole

Increase reservoir contact

Avoid coning

Reduce flux rates for thin pays

Minimize compaction issues

Improve sweep

BG

Improve sweep

Stitch compartmentalized reservoirs

Reduce risk of sand production

* Open hole completions increase operational complexity and

pose more completion risk

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

BG

Are there reactive shales

Reservoir fracture pressure window

Zonal isolation

Sand production at the onset of depletion

Is it a high risk environment subsea

Particle Size Distribution (PSD)

40/6020/40

Cumulative Log Diagram

60%70%80%90%

100%

C

u

m

.

%

b

y

W

e

i

g

h

t

Saucier SizingSample BWell Sorted

D50

BG

0%10%20%30%40%50%

0.00010.00100.01000.1000Grain Diameter (inches)

C

u

m

.

%

b

y

W

e

i

g

h

t

0.000210.006

0.017

0.003

Sample APoorly Sorted

DD

40

90

0 0030 001 3= =.

.

Sample BDD40

90

0 0060 00021 29= =

.

.

Sample A

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)

BG

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)

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

BG

Probability of parting casing/liner top

Close proximity to water

HHP limitations

Sand Control

Borehole Stability

Sustained ProductionPoor 1

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Completion Options

Best Completions

Based On

Production

BG

Sustained Production

Zonal Isolation

Rig Time Savings

Execution Logistics

10 9 11 11 13 12

Fair 2

Good 3

Sand ControlGeographic Distribution - Completion Type

Sand Prone ReservoirsSand Prone ReservoirsSand Prone ReservoirsSand Prone Reservoirs

GoM

Baku

Saudi Arabia

North Sea

Egypt

Italy

Eastern Canada

Alaska

CH Fracpack

OH Water Pack

SAS

OH Water Pack

SAS

OH Gravel Pack

BG

Brazil

Nigeria

Angola

Saudi ArabiaVenezuela and Trinidad

India

Australia

South China Sea

OH Gravel Pack

APS

Water Pack

OH Water Pack

CH Fracpack

CH FP

OH GP

APS

Water Pack

Questions?

BG

Questions?