fluid saturations - webs · the pendular grain contacts and at pore throaths. the irreducible...

AZMAN IKHSAN/SKP3323

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Fluid Saturation

Expected saturation values

Saturation from laboratory

measurements

It is expected that students will be able to:

define saturation of fluids in porous rocks

calculate saturation

explain saturation measurement using

Retort, Soxhlet Extractor and calculate the

saturation values

Fluid Saturations

SKM2313/RESERVOIR ROCK AND FLUID PROPERTIESAZMAN BIN IKHSAN

PERTOLEUM ENGINEERINGFPREE

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RESERVOIR ROCK PROPERTIES

Fluid Saturations

• Define

What is fluid saturations in porous rock?

• Laboratory methods saturation determinationExplain and calculate saturation values from Retort and

Soxhlex Extractor

• Application of saturation data

Examples on the use of saturation reservoir engineering calculations



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Fluid Saturations• Definition

Generally, a hydrocarbon formation was initially filled with water. Hydrocarbon

migrated into the formation and filled fraction of he void spaces that were

initially filled by water. As a result the formation is now filled with water and

hydrocarbon, and the quantity of each fluid must be determined.



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Fluid Saturations• Definition

Fluid saturation in a porous media is a fraction of the fluid in the pore spaces

of the rock.

pore of volume

pore in the me water vol

If

p

w

V

V

fractionin satiration water

by,given is pore in the saturation water The

w

p

ww

S

V

VS

percentin saturation water

% 100

or

w

p

ww

S

*V

VS



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Fluid Saturations• Methods to determine saturation

Many methods are available, only 3 will be discussed:

1. Retort Distillation Method

2. Solvent extraction (Soxhlet Extractor and Dean-Stark)

3. Centrifugal Method



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Increase temperature up to 1000 - 2000 0F

1. Retort Distillation Method

Water of

crystallization

Interstitial water



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Extract until there is no more

increment of water collected

2. Solvent extraction (Soxhlet Extractor and Dean-Stark)

fractionin saturation water

w

p

w

w

S

V

VS

fractionin saturation oil

(cc) pore of volume* (gm/cc)density oil

(gm) water ofweight - (gm) core dried ofweight - (gm) core saturated ofweight

o

o

S

S



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A solvent is injected into the centrifuge

just off center. Owing to centrifugal

force it is thrown to the outer radii,

being forced to pass through the core

sample. The solvent remove the water

and oil from the core. The outlet fluid is

trapped, and the quantity of water in

the core is measured.

3. Centrifugal Method

Solvent tube

Core plugs



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Fluid content from the core sample (core taken from field) has change

from its original content in the reservoir.

Factors affecting fluid saturations of cores

a. Coring in the formation is influenced by drilling fluid invasion

during drilling

b. Bringing the core sample to the surface will cause pressure

decline and the expansion of water, oil and gas



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Fluid Saturations• Use of saturation data from lab.

1. Determine level of oil-water contact

2. Not accurate to be used in calculating hydrocarbon

volume in the reservoir due to the above reasons



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Fluid Saturations

foot)-bbl/(acre 7587

STB place,-in oil initial

bbl/STB factor, volumeformation oil

fraction porosity,

kaki formation, of tickness

acres formation, of area

fraction ,saturation water

/)1(****7758

place-in oil Initial

N

B

h

A

S

BShAN

oi

w

oiwi

• Use of saturation data from lab.

1. Determine level of oil-water contact

2. Not accurate to be used in calculating

hydrocarbon volume in the reservoir due to

the above reasons



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Fluid Saturations• Several terms on saturation

Connate water (Air konat) (Swc): water entraped in the

intertices of the rock (either sedimentary or extrusive

igneous) at the time the rock was deposited.

Interstitial water (air celahan): Water that occurs

naturally within the pores of rock. Water from

fluids introduced to a formation through drilling or

other interference, such as mud and seawater,

does not constitute interstitial water. Interstitial

water, or formation water, might not have been

the water present when the rock originally formed.

In contrast, connate water is the water trapped in

the pores of a rock during its formation, also

called fossil water.



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Fluid Saturations• Beberapa istilah ketepuan air

Irreducible water saturation (Ketepuan air tak terkurang ) (Swir): the fraction of pore

volume occupied by water in a resevoir at maximum hydrocarbon saturation. In

water-wet rock, it represents the layer of adsorbed water coating solid surfaces and

the pendular grain contacts and at pore throaths. The irreducible saturation of a fluid

is the minimum saturation of that fluid attainable when that fluid is displaced from a

porous medium by another fluid immmiscible with the first.

The lowest water saturation, that can be achieved in a core plug by displacing the

water by oil or gas. The state is usually achieved by flowing oil or gas through a

water-saturated sample, or spinning it in a centrifuge to displace the water with oil or

gas. The term is somewhat imprecise because the irreducible water saturation is

dependent on the final drive pressure (when flowing oil or gas) or the maximum

speed of rotation (in a centrifuge). The related term connate water saturation is the

lowest water saturation found in situ.

Residual oil (minyak baki) (Sor): Oil remaining in the reservoir rock after the

flushing or invasion process, or at the end of a specific recovery process

or escape process.



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fluid saturations - webs · the pendular grain contacts and at pore throaths. the irreducible...

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