SAGD completion design and challenges

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Statoil’s First Oil Sands Field Development in Canada – Completion Challenges and Design

SPE Stavanger, October 12th 2011 1-

Classification: Internal

2011-08-15

Statoil’s Oil Sands Land Position ¾1,100 square kilometres of oil sands leases in the Athabasca region, Alberta, Canada ¾The reserve potential are 2.2 billion bbl of recoverable bitumen ¾The Kai Kos Dehseh(*) full field SAGD project development will produce 200,000 b/d when all 4 phases have been developed ¾Several hundreds SAGD wells are required to meet the production goals Note: 40% of the project is farmed down to PTTEP.

First SAGD Project ¾Our Leismer Demonstration Project is the first phase to be developed using SAGD technology and the facility is now producing first oil (Jan 2011). ¾The project is located north-east of Edmonton, 30km west of Conklin ¾23 well pairs on 4 well pads, plus a central processing facility to generate steam ¾18,800 bbl/d capacity plant

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Classification: Internal

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McMurray Formation Reservoir Properties Parameter Depth (mKB) Temperature (C) Initial pressure (kPa) Oil gravity (API)

Value 400 10 2200 6-9

Oil viscosity (cp) @ initial temperature @ SAGD temperature Solution GOR (m3/m3)

>1 000 000 5-8 2-3

Porosity (fraction)

0.33

Permeability (D)

2-12

Oil saturation (fraction)

~0.8

Gross SAGD pay (m)

15-35

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SAGD Well Pair’s

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SAGD Circulation Phase

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SAGD Operation Phase

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A Perfect Steam Chamber

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Leismer Demonstration Plan BASE CASE: ¾700 – 780 m Hz sections ¾ 8-5/8” slotted liners (Injectors) ¾ 7” slotted liners (Producers) ¾ ESP artificial lift system

Pressure cycling (2) 8-5/8” producers (4) Wire wrapped screen (8) Solvent co-injection (3) Rotaflex lift system (2) PCP lift system (2)

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Completion Design – Circulation Phase

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Why Sand Control? ¾Well sanding and plugging ¾Erosion and failure of pumps ¾Erosion of surface equipment ¾Treating, separation and sand disposal costs

Slotted Liner ¾Straight Slots – Slots are cut with equal width through the wall of the pipe both ID and OD. Common applications are SAGD injector wells. ¾Seamed Keystone Slots* – Slots are narrow at the liner surface and increasing in width at the interior, this let sand that does enter pass easily through the slots without plugging. * Or Rolled Top Slots

Slot Pattern ¾ Slotted liners are typically cut with four rows per slotted foot, with rows staggered, 50% offset of each other. ¾ Rows are staggered in order to preserve most of the pipe's original strength and integrity. Moreover, when slots are evenly distributed over the pipe surface, drainage is more efficient.

Wire Wrapped Screen ¾ All-Welded Wire Wrapped base pipe screen ¾ Wedge Wire Screen allows the user to maximize the open area to flow while maintaining a strict gauge as low as 0.003” (75 micron) ¾ The large inlet area allows higher production rates with lower entrance velocity and minimal pressure drop

Plugging of Slots

Plugging of Slotted Liner Vs. WWS

Slot Damage ¾Installation loads ¾ Axial compression ¾ Curvature ¾ Torque

Bird caging

¾Operational loads ¾ Thermal Strain ¾ Axial Strain Localization ¾ External Pressure

Alternative Bird caging

Twisting

Finite Element Modeling of Slotted Liner

Finite Element Modeling of WWS

Collapse Resistance

20

40

31.4 MPa

219.1 mm, 53.6 kg/m L80 Slotted Liner (Stagger)

5

219.1 mm, 53.6 kg/m L80 Slotted Liner (Gang) 219.1 mm, 47.6 kg/m L80 Slotted Liner (Stagger)

20

Formation Freacture Pressure

10

177.8 mm, 43.2 kg/m L80 Slotted Liner (Stagger) 177.8 mm, 38.7 kg/m L80 Slotted Liner (Stagger)

219.1 mm, 47.6 kg/m L80 Slotted Liner (Gang)

0

0

300

350

400

450

500

550

600

Slot Density (slots/m)

650

700

300

350

400

450

500

Slot Density (slots/m)

550

600

650

177.8 mm, 38.7 kg/m L80 WWS  (12.7 mm holes @ 433 holes/m)

Formation Freacture Pressure

10

30 177.8 mm, 38.7 kg/m L80 WWS  (12.7 mm holes @ 236 holes/m)

15

Collapse Resistance (MPa)

Collapse Resistance (MPa)

33.3 MPa

700

Well Bore Hydraulics 6000kPa Max. Injection Pressure

Circulation Pressure & Quality Constraints

6000

Tubing Pressure Tubing Quality

Annulus Pressure Annulus Quality

100% 90%

5000

80%

90% Min. Inj. quality

Pressure (kPa)

60% 50%

3000

40% 2000

30% 20%

1000 5% Max. Quality heel return

10%

1000kPa Min. Return Pressure

10% Min. Toe quality

0 0 Well Head

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200

400

600 Heel

800

1000

Length (m)

1200

1400

0% 1600 Toe

Steam Quality (%)

70%

4000

The Dog Bone Pattern

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Uniform Steam Distribution

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Tubing Design Challenges ¾Multi-tubing string design ¾ Heel and toe strings ¾ Guide string ¾ Coiled tubing string ¾Deployment ¾ Casing clearance ¾ Well bore Friction ¾ Buckling ¾Tubing expansion ¾Tubing entanglement

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Down Hole Monitoring Challenges ¾Monitoring of steam chamber development ¾Accurate and reliable measurements at high temperatures ¾Hydrogen darkening of fibre optic cable ¾Deployment and change-outs

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Wellhead & Xmas Tree Challenges • Well control at all stages • High temperature seals • Wellhead growth • Facilitate multi-string design • Cost efficient well intervention and workover operations • Standardization and re-use of equipment

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Completion Design – Operations Phase

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ESP High Temperature Challenges ¾ Materials & thermal growth ¾ Well bore geometry ¾ Steam flashing ¾ Abrasives & scale ¾ Down hole monitoring ¾ Deployment ¾ Efficient change-out ¾ Finding root cause of failure

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Thank You !

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