STEAM FLOODING

Outline

Introduction steam drive Mechanism Cyclic Stem Stimulution Advantages & disadvantages EOR Stem Injection Criteria Limitiation

Steam flooding technogy, introduced in the 1970. It is the type of thermal EOR method are generally

applicable to heavy,viscous crudes, and involve the

introduction of thermal energy or steam into the

reservoir to raise the temperature of the oil and reduce

its viscosity, increase in permeability. It is applicable for low depth well.

Steam drive

Steam is injected into several injection wells

while the oil is produced from other wells.

Multi-well operation in regular pattern

Inject steam into one or more wells

Recovery factor (RF) ≈ 50% OOIP

• Some thermal energy is lost in heating the formation rock and water

• The steam moves through the reservoir and comes in contact with cold oil, rock, and water.

• As the steam comes in contact with the cold environment, it condenses and a hot water bank is formed. This hot water bank acts as a water flood and pushes additional oil to the producing wells.

Mechanism

Mechanisms of this processMechanisms of this process

•– include thermal expansion of the crude oil,

•–viscosity reduction of the crude oil,

•–changes in subsurface forces as the reservoir temperature increases.

•This application is limited due to loss of heat energy. In deep wells,

steam will be converted to liquid water

•More expensive than cyclic steam stimulation.

• A method of thermal recovery in which a well is injected with steam and then subsequently put back on production.

• Single well operation

• Injection/production

• cycle:

• – Steam injection

• – shut-in (soak)

• – Oil production

• A cyclic steam-injection process includes three stages.

• The first stage is injection, during which a slug of steam is introduced into the reservoir.

• The second stage, or soak phase, requires that the well be shut in for several days to allow uniform heat distribution to thin the oil.

limitationOil saturations must be quite high and the pay zone should be more than 20 ft thick to minimize heat losses to adjacent formations.

Lighter, less viscous crude oils can be steam flooded but normally will not be if the reservoir will respond to an ordinary water flood.

Steam flooding is primarily applicable to viscous oils in massive, high permeability sandstones or unconsolidated sands.

Steam flooding is not normally used in carbonate reservoirs.

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