ALKALINE FLOODING

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.

EOR INCLUDES

Chemical flooding

Gas injection

Thermal flooding

Chemical flooding consist of

Polymerflooding

Surfactant flooding

Alkaline flooding

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 floodingOperations.Alkaline flooding is also known as Caustic flooding.

HOW THIS WORKS INSIDE THE RESERVOIR?

The alkaline chemicals reacts with certain types of oil,forming surfactants inside the reservoirEventually,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.

CONSIDERATIONS FOR USING…

Alkaline flooding is not recommended for carbonate reservoirs due to the abundance ofCalcium:The mixture between the alkaline chemical and the calcium ions can produce Hydroxide precipitation that may damage the formation.

CRITERIA FOR USING… CRUDE OIL

Gravity 13 – 35 APIViscosity <200 cp

RESERVOIR

Avg. K >20 mdDepth <about 9000 ftTemp. <200 *F preferred

EFFECTIVENESS OF DIFF. CHEMICALS…

i. Sodium Orthosillicate upto 100%

ii.Sodium Carbonate upto 65%

iii.Sodium Hydroxide upto 80%

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.

PROBLEMS IN USING…

1.Scaling and plugging in the producing wells.

2.High caustic consumption.

THANK YOU