FKPE7. Workshop

Bohrlochgeophysik und Gesteinsphysik

Geozentrum, Hannover, 23. - 24. Okt. 2003

Relationship between electrical and hydraulic properties of reservoir rocks

DFG SPP 1135: Dynamics of sedimentary basins

Georg Nover, Stephanie Heik am p, M ichael Poelchau, H. D ürrast* , S. Siegesm und*

M ineralogisch-Petrologisches Institut, Bonn

* IGDL, Göttingen Outline Drillings: Schleswig, Fehmarn, Oldenbüttel, Glückstadt, Lingen Petrophysics:

density, porositypressure dependence of the permeability,complex electrical conductivity and its pressure dependencerelation to transport properties

Conclusion & cooperations

Petrophysical properties of reservoir rocks

Dürrast, 1997

Petrophysics: DensityRotliegendes: conglomerate: clay, sandstone, coarse silt

Matrix density Porosity Mineralogical composition

Petrophysics: PorosityFehmarn Z1; Schleswig Z1; Glückstadt T1

0 2 4 6 8 1 0p o r o s i t y

5 0 0 0

4 5 0 0

4 0 0 0

3 5 0 0

3 0 0 0

2 5 0 0

2 0 0 0

dep

th

T o n s t e i n S a n d s t e i n T o n s t e i n

K a l k

T o n s t e i n

S a n d s t e i n K o n g l o m e r a t

V u l k a n i t

B r e c c i e

P o r o s i t y v o l %F e h m a r n Z 1

0 2 4 6 8 1 0 1 2p o r o s i t y v o l %

6 0 0 0

5 0 0 0

4 0 0 0

3 0 0 0

dep

th m

A n h y d r i t D o l o m i t

S a n d s t e i n

S a n d s t e i n S a n d s t e i nK o n g l o m e r a tT o n s t e i n T o n s t e i n

V u l k a n i t

T o n s t e i n

T o n s t e i n

G l ü c k s t a d t T 1

P o r o s i t yS c h l e s w i g S Z 1 & G l ü c k s t a d t T 1

1. Archimedian, 2. Volumetric

Petrophysics: Permeability Pressure Dependence; instationary technique

1 autoklav2 sample with fittings and shrink tubing3 confing pressure

s a m p l e d i a m e t e r : 1 0 - 4 5 m m ;

s a m p l e l e n g t h : 1 0 - 6 0 m m c o n f i n i n g p r e s s u r e : u p t o 3 5 0 M P a f l o w m e d i a : g a s ( a r g o n ) ,

f l u i d s ( w a t e r , o i l ) p e r m e a b i l i t y r a n g e : m D - n D ( 1 0 - 1 5 - 1 0 - 2 1 m 2 )

Gas-Fluid Gas-FluidPressureOUTPUT

ConstantPressureINPUT

1

2

3

P

time

P = constP

Petrophysics, results: Pressure Dependence of the Permeability Anisotropy

0 4 0 8 0 1 2 0 1 6 0 2 0 0p r e s s u r e ( M P a )

0 . 0 1

0 . 1

1

1 0

1 0 0

1 0 0 0

1 0 0 0 0

perm

eabi

lity

( D

)

2 Z2 Y3 Z3 Y2 0 Y2 0 Z3 1 Z3 1 Y3 9 Z3 9 Y3 2 Y1 Z1 Y

0 2 0 4 0 6 0 8 0 1 0 0P r e s s u r e [ M P a ]

1 E - 0 2 2

1 E - 0 2 1

1 E - 0 2 0

1 E - 0 1 9

1 E - 0 1 8

Per

mea

bilit

y k

[m2 ]

4 6 3 8 . 2 7 m a x i a l4 6 3 8 . 3 4 m r a d i a l

F e h m a r n Z 1

Lingen limestone

0 4 0 8 0 1 2 0 1 6 0P r e s s u r e [ M P a ]

1 E - 0 2 3

1 E - 0 2 2

1 E - 0 2 1

1 E - 0 2 0

1 E - 0 1 9

1 E - 0 1 8

1 E - 0 1 7

1 E - 0 1 6

Per

mea

bilit

y k

[m2 ]

4 6 3 8 . 2 7 m a x i a l4 6 3 8 . 3 4 m r a d i a l

4 5 7 3 . 3 m a x i a l4 5 7 3 . 3 7 m r a d i a l

4 2 6 3 . 7 2 m a x i a l4 2 6 3 . 8 m r a d i a l

3 7 3 6 . 6 6 m a x i a l3 7 3 6 . 6 4 m r a d i a l

4 9 9 2 . 3 7 m a x i a l4 9 2 2 . 4 3 m r a d i a l

F e h m a r n Z 1

Anisotropy

Fehmarn

Permeabiliy: Pressure dependence; AnisotropySandstones from a tight gas reservoir, NW Germany

0 2 0 4 0 6 0 8 0 1 0 0

p r e s s u e ( M P a )

0 . 1

1 . 0

1 0 . 0

perm

eabi

lity

(uD

)

4 x4 y4 z8 x8 y8 z

X Y

Petrophysics: Electrical Properties and their relation

Degree of interconnection

Electrolyte,Double layer

Electrolytic charge transport – Model

- - - - - - - - - - - - - - - - - - - -

- - - - - - - - - - - - - - - - - - -m i n e r a l s u r f a c e

l i t h o l o g y e l e c t r o n i c m o d e l

n e g a t i v e c h a r g e d

" f r e e " m o b i l i t y , u n h i n d e r e d m o v e m e n t

e l e c t r o l y t e

+ ++ / - + / -

+ + + / - + / -+ / -

P o l a r i s a t i o n

c a t i o n s d i p o l s

p o l a r i s a t i o n u n h i n d e r e d m o v e m e n t0 5 0 0 1 0 0 0 1 5 0 0 2 0 0 0

Z ` ` ( O h m )

0

2 0 0

4 0 0

6 0 0

8 0 0

1 0 0 0

Z`

(Oh

m)

1 k 1 k

1 F 1 F

Ω Ω

µ m

Complex Electrical Conductivity: 5 Hz – 1 MHzPressure Dependence

0

500

1000

2000

Computer

ACImpedanceAnalyzer

1kHz - 1 MHz

1

34

2

5

6

1 piston

2 autoclave

3 pressure transducer

4 m anom eter

5 sam ple

6 electrical connections

7 Im pedance analyser

Pressure dependence

0 2 0 4 0 6 0 8 0 1 0 0

p r e s s u e ( M P a )

0 . 1

1 . 0

1 0 . 0

perm

eabi

lity

(uD

)

4 x4 y4 z8 x8 y8 z

0 2 0 4 0 6 0 8 0 1 0 0

p r e s s u r e ( M P a )

0 . 0 0 0 1

0 . 0 0 1 0

0 . 0 1 0 0

cond

ucti

vity

(S/

m)

4 x4 y4 z8 x8 y8 z

Permeability Volume conductivity

Crossplot: Porosity -- Volume conductivityAnisotropy

0 . 1 1 . 0 1 0 . 0

p o r o s i t y ( % )

0 . 0 0 1

0 . 0 1 0

0 . 1 0 0

cond

ucti

vity

(S/

m) 4 x

4 y4 z8 x8 y8 z3 x3 y3 z2 8 4 x2 8 4 y2 8 4 z

1 1 0 1 0 0

p o r o s i t y ( % )

1 0

1 0 0

1 0 0 0

form

atio

nfa

ctor

F

m a r b l es a n d s t o n e

s a n d s t o n e

m a r b l e

Anisotropy of electrical conductivity

Crossplot: Pressure dependencePermeability -- Volume conductivity

1 0 1 0 0 1 0 0 0 1 0 0 0 0

f o r m a t i o n f a c t o r

0

1

1 0pe

rmea

bilit

y (u

D)

4 x ( - 0 . 7 )4 y ( - 1 . 0 3 )4 z ( - 1 . 0 1 )8 x ( - 4 . 4 1 )8 y ( - 4 . 9 4 )8 z ( - 1 0 . 3 )

Complex response: Measured data – Model

8 x

0 2 0 4 0 6 0 8 0 1 0 0

p r e s s u r e ( M P a )

4 0

8 0

1 2 0

1 6 0

2 0 0

resi

stiv

ity

(Ωm

)

8 x

0 4 0 8 0 1 2 0 1 6 0Z ' ( Ω m )

- 8 0

- 6 0

- 4 0

- 2 0

0

Z''

(Ωm

)

0 2 0 4 0 6 0 8 0 1 0 0

p r e s s u r e ( M P a )

0

1

1 0

1 0 0

8 xR 1R 2C 2 ( * e - 6 )R 3C 3 ( * e - 4 )

Interpretation:RC-equivalent circuit(2 relaxation model) (R1||C1)_(R2||C2) bulk conductivity surface conductivity Relaxation time (time constant of polarisation)

Frequency 1 kHz

1 MHz

Crossplot: pressure dependence of the relaxation time

1 1 0 1 0 0

p r e s s u r e ( M P a )

0 . 0 0 0 0 0 0 1

0 . 0 0 0 0 0 1 0

0 . 0 0 0 0 1 0 0

0 . 0 0 0 1 0 0 0

rela

xati

on

4 x4 y4 z8 x8 y8 z

Petrophysics: AC-Impedance, Results

Pressure

Conclusion & Cooperations

RWTH, Aachen: Petrophysics, permeability, porosity, Data BaseUni Münster: Electrical conductivity, correlation lab-borehole dataGFZ: BET surface, porosityBGR: Carbon enhanced conductivityUni Göttingen: Correlation of lab data: Vp, Vs, permeability, el. Cond.

ConclusionElectrical rock properties depend on: petrophysical parameters, porosity, permeability, aspect ratio Fabric, texture, grain size distribution, metamorphic overprint Anisotropy of layering Degree of interconnection of the pores But,the correlation between electrical and hydraulic properties still requires further experiments.