SPE 180370-MS Wettability Alteration in Reservoirs: How...

SPE 180370-MS Wettability Alteration in Reservoirs: How it Applies

to Alaskan Oil Production.

Geoffrey Thyne, ESal

Presentation Outline

Slide 2

Paper 180370-MS Wettability Alteration in Reservoirs: How it Applies to Alaskan Oil Production Geoffrey Thyne

• Wettability • Field Cases • Screening Criteria • Screening Results • Best Candidates • Questions

Oil Production

Slide 3


• Current situation • Decline curves with wettability alteration

Why Alter Wettability? Slide 4


• No change in normal operations • Increase in recovery is HIGH (5-25% OOIP) • Increase reserves for minimal investment • Low additional production cost ($0.50 to $3 per bbl) • Works in clastics and carbonates • Rapid response (3-9 months) • No surfactants ($$) • Minimal environmental impact • No reservoir damage

How does it work?

Slide 5


Successes and Failures Slide 6


Successes (conventional) BP - North Slope – SWTT and pilot for SS field (15% OOIP). Conoco-Phillips - North Sea –flooding deep chalk field (30% OOIP). Shell - Syria –flooded SS field (10-15% OOIP). Saudi Aramco – Carbonate field, 2 SWTT’s, 10-20% OOIP

Failures (conventional)

Independents - Wyoming –Minnelusa SS – no increase in recovery. Stat Oil - North Sea –Stratfjord SS - minimal response (<2% OOIP). Zichebashskoe Field, Russia, SS – 4% OOIP

Wettability… Slide 7


• In petroleum reservoirs, wettability is the tendency of oil to adhere to the reservoir rock surfaces limiting oil movement and recovery.

• Wettability is recognized as a major control on oil mobility and amount of recovery.

FESEM images - Sandstone surface coated with oil, at pH of 4 in 0.01 M NaCl

Wettability Slide 8


• Reservoir wettability is the equilibrium of water, rock and oil.

• Wettability is major control on recovery.

• “Hydrocarbon-wet systems retard hydrocarbon mobility”.

• “Water-wet systems promote hydrocarbon mobility”.

Oil-Wet Water-Wet

Wettability Slide 9


Recovery = Oil Release + Oil Mobility

Sweet Spot Optimum water chemistry for rock and oil

What do you need? Slide 10


• Water chemistry favorable to change • Rock with required surface sites • Oil with sufficient polar components • Favorable reservoir conditions

– Temperature – Good waterflood

Dilution of Salinity in Sandstone and Carbonate Slide 11


Fathi et al. 2011 North Sea Chalk SPE 180370 - Alaska SS Lab and Field

Rock Surface Control Slide 12


Oil must have polar components Slide 13


Fields – good waterflood and OOIP Slide 14


Fields – good waterflood and OOIP Slide 15


Screening for Good Candidates Slide 16


• Use lab and field data to determine empirical relationships. • Input rock, water, oil and field properties to algorithm and calculate

aggregate weighted score.

Field Water

Oil Rock

Alaskan Oil Fields

Screening Results Slide 17


Best Candidates Slide 18


• The best candidates were fields with good current recovery indicating successful waterflood conditions, and high OOIP.

• Prudhoe, KRU-Kuparuk, CRU-Alpine, EU-Endicott and PBU-Lisburne on the North Slope

• All the fields in the Cook Inlet appear to be attractive candidates and the potential incremental production would be 360 million barrels.

• On the North Slope the potential incremental oil recovery may exceed 3.7 billion additional barrels.

Acknowledgements / Thank You / Questions

Islin Munisteri State of Alaska - Division of Oil and Gas Susan Nash of AAPG Teresa Nealon – ESal LLC

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SPE 180370-MS Wettability Alteration in Reservoirs: How...

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