2. WHAT IS EOR?
Enhanced oil recovery or Improved oil
recovery is the special technique in which oil
is extracted From a reservoir after primary
and secondary recovery methods.It can be
used at the start of production also if the
reservoir is not suitable for primary or
secondary recovery.
3.
4. EOR INCLUDES
Chemical flooding
Gas injection
Thermal flooding
6. WHAT IS ALKALINE FLOODING?
It is an EOR method in which an alkaline chemical
such as Sodium hydroxide,Sodium
Orthosillicate or Sodium carbonate is injected
during polymer flooding or water flooding
Operations.Alkaline flooding is also known as
Caustic flooding.
7. HOW THIS WORKS INSIDE THE
RESERVOIR?
The alkaline chemicals reacts with certain types
of oil,forming surfactants inside the reservoir
Eventually,the surfactants reduce the interfacial
tension between oil and water and trigger an
Increase in oil production.Wetting characteristics
of the reservoir also can change due to Formation
of surfactants inside the reservoir or it can be due
to some other reasons.
8.
9. CONSIDERATIONS FOR USING…
Alkaline flooding is not recommended for
carbonate reservoirs due to the abundance
of
Calcium:The mixture between the alkaline
chemical and the calcium ions can produce
Hydroxide precipitation that may damage
the formation.
10. CRITERIA FOR USING…
CRUDE OIL
Gravity 13 – 35 API
Viscosity <200 cp
RESERVOIR
Avg. K >20 md
Depth <about 9000 ft
Temp. <200 *F preferred
12. ADVANTAGES AND LATEST
TECHNOLOGY…
Alkaline flooding is usually more efficient if the
acid content of the reservoir oil is
Relatively high.
A new modification to the process is the addition
of surfactant and polymer to the alkali,
Giving rise to an Alkaline-surfactant-
polymer(ASP) EOR method.
This method has shown to be an effective,less
costly form of micellar-polymer flooding.
