Crossplots for Porosity, Lithology and Saturation

4-17

CP

Porosity and Lithology Determination fromFormation Density Log and CNL* Compensated Neutron LogFor CNL logs before 1986, or labeled NPHI

CP-1d

0 10 20 30 40

φCNLcor, neutron porosity index (p.u.) (apparent limestone porosity)

Salt water, liquid-filled holes (ρf = 1.1)

1.9

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

ρ b, b

ulk

dens

ity (

g/cm

3 )

φ D, d

ensi

ty p

oros

ity (

p.u.

) (ρ

ma

= 2

.71;

ρf =

1.1

)

45

40

35

30

25

20

15

10

5

0

–5

–10

–15

Porosity

Sulfur Salt

Approximategascorrection

0

Anhyd

rite

PolyhaliteLangbeinite

Calcite (li

mestone)

0

45

5

15

10

20

25

30

35

40

Dolom

ite

30

0

5

15

10

20

25

35

40

Quartz sa

ndstone

30

0

5

15

10

20

25

35

40

45

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