introduction to Nitrogen Flooding, Conditions of Nitrogen Flooding, Source of Nitrogen, Objectives of Nitrogen Flooding, Procedure of Nitrogen Flooding, EOR Methods

1. NITROGEN FLOODING
MUBARAK ALI RAO
mubarik.ali43@yahoo.com
international member of
SPE 4353073

2. Contents of Presentation
• Introduction
• Conditions
• Source of Nitrogen
• Objectives
• Procedure

3. Introduction
• Nitrogen has long been successfully used as the injection fluid for EOR
and widely used in oil field operations for gas cycling, reservoir pressure
maintenance, and gas lift.
• The costs and limitations on the availability of natural gas and CO2 have
made nitrogen an economic alternative for oil recovery by miscible gas
displacement.
• Nitrogen is usually cheaper than CO2 or a hydrocarbon derived gas for
displacement in EOR applications and has the added benefit of being
non-corrosive.

4. Conditions
• The reservoir oil must be rich in ethane through hexane (C2-C6) or
lighter hydrocarbons. These crudes are characterized as "light oils"
having an API gravity higher than 35 degrees.
• The oil should have a high formation-volume factor – the capability of
absorbing added gas under reservoir conditions.
• The oil should be under saturated or low in methane (C1).
• The reservoir should be at least 5,000 feet deep to withstand the high
injection pressure (in excess of 5,000 psi) necessary for the oil to attain
miscibility with nitrogen without fracturing the producing formation.

5.  Source of Nitrogen
- Cryogenic nitrogen plant
• Nitrogen, as an element of great technical
importance, can be produced in a cryogenic
nitrogen plant with a purity of more than
99.9999%.
• Air inside a distillation column is separated
at cryogenic temperatures (about 100K/-
173°C) to produce high purity nitrogen with
1ppm of impurities.
• The process is based on the air separation,
which was invented by Dr. Carl von Linde in
1895.
- Natural Reservoirs are also the
source of nitrogen.

6. Objectives
• Increase oil recovery
• Reduce interfacial tension
• Reduce viscosity of oil
• Increase sweep efficiency
• Increase oil mobility

7. Procedure
• when nitrogen is injected into a reservoir, it forms a miscible front by vaporizing some of the
lighter components from the oil.
• This gas, now enriched to some extent, continues to move away from the injection wells,
contacting new oil and vaporizing more components, thereby enriching itself still further.
• As this action continues, the leading edge of this gas front becomes so enriched that it goes into
solution, or becomes miscible, with the reservoir oil.
• At this time, the interface between the oil and gas disappears, and the fluids blend as one.
• Continued injection of nitrogen pushes the miscible front (which continually renews itself)
through the reservoir, moving a bank of displaced oil toward production wells.
• Water slugs are injected alternately with the nitrogen to increase the sweep efficiency and oil
recovery.
• At the surface, the produced reservoir fluids may be separated

9. Thank You For Your Attention