8/14/2019 wli14

1/28

Saturation

Water Saturation

8/14/2019 wli14

2/28

Saturation

Saturation DeterminationObjectives :

Resistivity and Partial Saturation

Archie Saturation Equation

Saturation Exponent n

Bulk Volume Fractions and

Moved Oil Plot MOP

8/14/2019 wli14

3/28

Saturation

Water Saturation

.

.w

BVW Vol WaterS

Vol Pore= =

8/14/2019 wli14

4/28

Saturation

Parallel TubesWater

8/14/2019 wli14

5/28

Saturation

Parallel TubesWater & Oil

8/14/2019 wli14

6/28

Saturation

Resistivity & Partial Saturation

Parallel Tubes: Hydrocarbon & Water

0

wRR

=

0

wRR

BVW=

w

t

RR

BVW=

w

w

t

RR

S=

Parallel Tubes: Water Bearing

8/14/2019 wli14

7/28

Saturation

Water Saturation

in resistivity terms, oil appears like glass

both are perfect insulators

water (electrolyte) is the only conductive

material

8/14/2019 wli14

8/28

Saturation

Resistivity & Partial Saturation

+ Tortuosity

Water

+ Tortuosity

Water & Hydrocarbon

0

w

m

RR

= w

t

w

RR

S

m

=m

8/14/2019 wli14

9/28

Saturation

Water &Hydrocarbon

8/14/2019 wli14

10/28

Saturation

Resistivity & Saturation

Parallel Tubes,Water-bearing

Parallel Tubes,

Partially Saturated

Add Tortuosity

0w

R

R =

wt

w

RR

S=

w

t m

w

aRRS

=m

8/14/2019 wli14

11/28

Saturation

Tortuosity (current path)

water-bearing

mid pore

oil-bearing(water-wet)

grain surface

Sw and exponentsmay differ somewhat

8/14/2019 wli14

12/28

Saturation

Tortuosity :water vs. oil-bearing

8/14/2019 wli14

13/28

Saturation

Saturation Exponent n

if oil occupies mid-pore space,(water-wet condition)

tortuosity may change with saturation or

wettability current path may change

n kept independent of m

8/14/2019 wli14

14/28

Saturation

Determination of Saturation Exponent n

Desaturation Cell measurements on coreplug . . .slope on log-log plot

Capillary Pressure Curves at irreducible

saturation OBM Core . . . recover l iquids in cleaning

Match Archie saturation by adjusting n

8/14/2019 wli14

15/28

Saturation

Desaturation Cell

8/14/2019 wli14

16/28

Saturation

8/14/2019 wli14

17/28

Saturation

Wettability

8/14/2019 wli14

18/28

Saturation

Effect of

Wettability

on n

8/14/2019 wli14

19/28

Saturation

Capillary Pressure & Water Level

8/14/2019 wli14

20/28

Saturation

Capillary

Pressure &

Saturation

8/14/2019 wli14

21/28

Saturation

Cap. Press. & Reservoir Quality

8/14/2019 wli14

22/28

Saturation

Dean-Stark

Cleaning

Apparatus

8/14/2019 wli14

23/28

Saturation

Sensitivityto n

8/14/2019 wli14

24/28

Saturation

Archie Saturation Equation

0n

w

t

RS

R=

wn

w

t

FRS

R=

w

nw m

t

aR

S R=

1n

wS I=

8/14/2019 wli14

25/28

Saturation

Nomograph for Archie Equation

8/14/2019 wli14

26/28

Saturation

Artificial intelligence is no match for

natural stupidity.

8/14/2019 wli14

27/28

Saturation

Saturation DeterminationSummary :

Water Saturation = vol.water / pore space

= BVW /

n can be determined by desaturation

measurements in a lab,or, by capillary pressure data in the irreducible zone

Archie Saturation Equation for clean reservoirs:

wn

w

t

FRS

R=

8/14/2019 wli14

28/28

Saturation