What is irreducible saturation?

What is irreducible saturation?

PetroWiki. The fraction of the pore space occupied by water when the hydrocarbon content is at maximum. This level of water can only be reduced by flow of very dry gas that evaporates the water. Typically shown as Swirr.

What is petroleum saturation?

1. n. [Geology] The relative amount of water, oil and gas in the pores of a rock, usually as a percentage of volume.

What is the difference between critical and irreducible water saturation?

Irreducible water saturation is the minimum interstitial water saturation existing above the water transition zone. Critical water saturation is the upper limit for formation water saturation above which a specific sample will produce a significant percentage of water with hydrocarbons.

What is critical oil saturation?

Critical saturation, whether gas or condensate, refers to the minimum saturation at which a phase becomes mobile. The endpoint saturation of a phase for a specific displacement process depends on: The structure of the porous material.

What is water saturation?

The fraction of water in a given pore space. It is expressed in volume/volume, percent or saturation units. Unless otherwise stated, water saturation is the fraction of formation water in the undisturbed zone. If used without qualification, the term usually refers to the effective water saturation.

How is water saturation measured?

Water saturation (Sw) can be measured directly from a sealed core, which is an expensive method, or it can be calculated from the Archie equation, which is less expensive. Sw can also be estimated using a graphical representation of the Archie equation known as the Pickett plot.

What is saturation formula?

Fluid saturation is expressed in terms of volume of fluid divided by total pore space. Gas saturation (Sg) = Vg ÷ Vp. Oil saturation (So) = Vo ÷ Vp. Water saturation (Sw) = Vw ÷ Vp. Total saturation of fluid is equation to 1, therefore this can mathematically be expressed like this.

How do you calculate oil saturation?

Fluid saturation is expressed in terms of volume of fluid divided by total pore space.

1. Gas saturation (Sg) = Vg ÷ Vp.
2. Oil saturation (So) = Vo ÷ Vp.
3. Water saturation (Sw) = Vw ÷ Vp.
4. Sg + So + Sw = 1.
5. References.

What is effective water saturation?

1. n. [Formation Evaluation] The fraction of water in the pore space corresponding to the effective porosity. It is expressed in volume/volume, percent, or saturation units. Unless otherwise stated, water saturation is the fraction of formation water in the undisturbed zone.

How is saturation calculated?

Percent saturation is calculated with the following formula: Iron/transferrin x 1.2. The percent saturation reference range is 15 – 50%.

What is effective saturation?

The fraction of water in the pore space corresponding to the effective porosity. The saturation is known as the total water saturation if the pore space is the total porosity, but is called effective water saturation if the pore space is the effective porosity.

How do I calculate saturation pressure?

Take the temperature of the system for which you want to determine saturation pressure. Record the temperature in degrees Celsius. Add 273 to the degrees Celsius to convert the temperature to Kelvins. Calculate saturation pressure using the Clausius-Clapeyron equation.

Which is the best definition of irreducible water saturation?

It also influences the production rate from that reservoir. Irreducible water saturation (sometimes called critical water saturation) defines the maximum water saturation that a formation with a given permeability and porosity can retain without producing water.

What is the irreducible water saturation of oil wet rock?

If the rock wettability is known from offset pool data, some limits can be set on the saturation. The irreducible water saturation is less than 15% in oil-wet rock and greater than 20% in water-wet rock. Productive water-wet sandstones usually have irreducible water saturations between 20% and 40%.

What happens to oil saturation as water saturation increases?

As water saturation increases (imbibition), oil relative permeability decreases and water relative permeability increases until no more oil can be displaced by water, at which point oil saturation = Sor (irreducible oil saturation) and water saturation Sw = 1 − Sor. At this point water relative permeability is at a maximum ( krwm ).

What are the different definitions of residual oil saturation?

Residual oil saturation depends on a number of factors and has different definitions. It is contingent on the rock type and properties, wettability, initial oil saturation (1 − Swi), the type of test and the test conditions. There are three principal definitions of residual oil saturation: