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Rock Properties

Enhanced Oil Recovery - EOR

Water Flooding remains the primary method of oil recovery, but typical recovery is 20% to 50% of the original oil in place. The oil remaining after water flood is a resource for various EOR techniques. Enhanced Oil Recovery is oil recovery by the injection of materials not normally present in the reservoir and the measurement of EOR Process is the difference in the oil actually produced versus the amount of oil projected to be produced had the EOR process not been initiated.

Enhanced Oil Recovery Services

  • Thermal Recovery
  • Gas Injection - Miscible or Immiscible
  • WAG Injection - Miscible or Immiscible
  • Chemical Injection
    • Surfactant/Alkaline
    • Polymer
Enhanced Oil Recovery

Environmental Condition Unit for Enhanced Oil Recovery Testing.

Thermal Recovery

A process in which heat is intentionally injected into a subsurface accumulation of organic compounds for the general purpose of improving the displacement and recovery efficiencies of those hydrocarbons. Thermal recovery processes are usually targeted towards viscous crudes, coals and oil shales.

  • Steam Injection
  • Hot Water
  • Distillation
Enhanced Oil Recovery - Thermal Recovery

Data Depicting Residual Oil Saturation after Water Drive and then after Steam Drive.


  • As temperature increases lighter fractions are distilled off similar to a refinery process Gasoline -> Kerosene -> Diesel (The Fractions act as a solvent reducing viscosity)
Enhanced Oil Recovery - Distillation

Cumulative Yield as a Function of the Distillation of Crude oil at Various Temperatures.

Viscosity Reduction

Enhanced Oil Recovery - Viscosity

Example of Viscosity Reduction Due to Increasing Temperature on a 15° API Middle East Oil.

Gas Injection - Gas Interactions with Oil

  • Dissolves in the Oil
    • Reduces viscosity, increases mobility, increases oil fractional flow
    • Reduces difference between oil and gas, lowers interfacial tension, possibly miscible
    • Causes oil saturation to increase, increases oil effective permeability
  • Oil components can vaporize into gas
    • Transports part of oil in more mobile phase
    • Reduces difference between oil and gas, lowers interfacial tension, possibly miscible
    • Shrinks oil, reduces oil saturation

Problems with Gas Injection

  • High mobility
  • Poor sweep
  • Supply

Chemical Flooding

  • Objectives
    • Improve viscosity ratio
    • Reduce interfacial tension
  • Materials Used
    • Polymers
    • Surfactants

Core Lab Services

  • Relative permeability
  • Recovery versus
    • Polymer concentration
    • Flow rate
    • Water composition

WAG is one method used to overcome above problems

  • Exploit water blockage, best in oil wet reservoir
  • Improves Sweep
  • Allows pressure maintenance with short gas supplies
Enhanced Oil Recovery - WAG

Cartoon Depicting Reducing Oil Saturation Due to Multiple Cycles of Water and Gas Injection (WAG)

  • Viscosity vs Shear Rate
  • Resistance Factor/Retention
  • Shear degradation
  • Polymer Retention

Enhanced Oil Recovery - Polymer Retention Graph

Variations in Oil Recovery Due to Changes in Oil/Water Viscosity Ratio

Enhanced Oil Recovery - Oil Recovery Fraction Graph

Oil Recovery Fraction as a Function of Surfactant Concentration