Surtek's ASP Design Procedures

Surtek has been directly involved with more chemical floods using interfacial tension agents than any other company world wide. Our laboratory design philosophy is a direct result of all of this experience. We believe a well designed system substantially reduces the risk of application. A poorly designed system will fail and lose money.

Surtek's outline of a laboratory design includes the following:

Fluid Design:

• Water and crude analysis
• Alkali IFT's
• Alkali-surfactant IFT's
• Phase behavior evaluations
• Static chemical consumption evaluations
• Cation exchange capacity
• Produced water compatibility evaluations

Fluid-Rock Compatibility

This work is done in either consolidated or unconsolidated linear reservoir core at reservoir temperature. This work determines the following:

• Relative permeability characteristics
• Chemical-rock compatibilities
• Injection of polymers in alkaline-surfactant solutions
• Rheological characteristics
• Polymer requirements for mobility control
• Chemical retention by reservoir core
• Oil saturation changes after each injected solution

Oil Recovery Radial Corefloods

Radial corefloods are preferred for final system selection because the laboratory oil recoveries compare very well with actual field performance. This comparison can be seen elsewhere in this web site for the Cambridge and Rapdan projects. The radial corefloods determine:

• Mobility ratio of water displacing crude oil
• End points of the relative permeability curve
• Amount of incremental ASP oil
• Amount of chemical retained
• Potential injection and flow problems
• Potential scale problems
• Variation of oil recovery with slug size
• Variation of oil recovery with slug modifications

The laboratory results for a SURTEK ASP™ design will determine whether a project should proceed or not. The curve below shows an envelope of laboratory designs that went to the field and one that did not.