AAG Presention 58400 r2

8/3/2019 AAG Presention 58400 r2

1/13

PERMEABILITY CORRELATIONS FOR

CARBONATE & OTHER ROCKS

Otis P. Armstrong, PE

Paper #58400 GSA Meeting 2003 Seattle Wa.

Presentation rev. 3


2/13

The form: k (md) =101.5(1/Sw-c - 1)1.9

(if k calc > 200, use 1, not 10)

It is presented to improve description of

potentially productive zones of carbonates.

Equations that do not use the form:(1/Sw-c - 1) cannot accurately describe k at

both low & high Swc, .i.e. at Swc=1, k must

equal zero.

Following Graphs are comparisons:


3/13

0.0

0.1

1

.0

10.0

100.0

1000.0

2.0 7.0 12.0 17.0 22.0 27.0 32.0

por %

kmd

opa BVW=0.02

Archie 1

Archie 2

Ar type 3

low por ss

Data


4/13

0.20.2

0.4

0.1

12.0

0.1

82.0

0.3

8.5

1.8

6.1

3.1

109.3

2.3

12.8

53.0

138.0

52.3

14.3

168.0

0.1

2.5

0.2

3.2

0.8

24.0

0.0

2.5

0.0

100.0

63.0

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03

core opa Sch97 Timur

Error w/ opa eqn is 10xs less than Sch97 and 20xs less Timur

Only 2 false negatives and 3 false positives at 1md cut point


5/13

Sw-c =BVW/ in Timors equation gives:Kmin ={92.6()

2.2/(Sw-c)}2 => min ={Kmin *BVW/92.6}0.313

and using these terms in the movable HC formula:

(Swc0.2

Swc)7760 = 7760{( Swc/)0.2

BVW}=BBL/AcFt = 7760{0.8(BVW)0.2 BVW} =>Kmin RULE : 7760[{Kmin /92.6}

0.25(BVW)0.513 BVW]

Other forms give similar results, but with limited range:Max Swc RULE: (BBL/AcFt)mo =7760(BVW)[(Swc)

-0.8 -1]min RULE : (BBL/AcFt)mo = 7760{[min

0.8 ]BVW0.2 BVW}

MOBILE HC VALUE

Provided, a min k can be established, mobile HC factor is simply a

mapping of the Bulk Volume Water Term, BVW. More correct K

forms, with (1/Swc - 1)n are just more complex. Below is a simple

derivation & recall (N^a)(N^-b)=N^(a-b) but ((N^a)^b)=N^(a*b):


6/13

Effect of permeability on min HC mov 0.025 BVW

100

125

150

175

200

225

250

275

300

325

350

375

400

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

min k, md

BBL/ac-

ftmove

opa

sch97

asquith oil

At each BVW, a MINIMUM mobility of BBL/AcFt is defined

using a parametric of Porosity or Connate Water or k.


7/13

63

0.23

0.2

0.4

0.1

12

0.05

82

0.3

9

1.8

63

1092

13

53

138

52

14

0.1

2.5

0.2

3.2

2

1

2

shale

??

?

?

?

??

?

?

>1>1

168

0.1

100

200

100

6

0.8

21

y = 1150x0.48

50

150

250

350

450

550

650

750

850

950

0.005 0.025 0.045 0.065 0.085 0.105 0.125 0.145BVW

b

bl/acft,mob

il

core & (md)

0.1md

Sw mx =0.525

0.3 mdPower (0.3 md)

Power (0.1md)

Plot of Core Data as BVW & Mobility Ratio: BBL/AcFt Minimum

Proposed at 0.2md line or 780BVW0.44


8/13

Increased mobility ~ increased chance depo is economical90% of all USA crb prdn from depo >130bbl/acft. US datashows: prospecting in low Siluran & older rocks; successrates 2-4xs higher if dolomites are tested compared to developing

simular age & limestone rocks.


9/13

2nd &Vug Carbs: =>bimodal pores

In logging terms: movable HC is:BBL/AcFt = 7760[a]*[(Rmf/Rxo) - (Rw/Rt) ]at irreducible H2O= 7760{ (Rw/aRt)}[ Swc)

-0.8 -1]Where a is term to make F = (a/2) , typically a=1 in carb.

Min bvw max bvw min bbl/AcFt mx bbl/AcFtvug carb 0.005 0.015 76 123

vug & IX carb 0.015 0.025 123 154

.Intr gran crb. 0.025 0.040 154 189

Chalk carb 0.050 0.100 189 283

780BVW0.44


10/13

Typical conditions, production < 900 & >130 bbl/ac-ft.Mobile HC expressed as BBL/Acft is a handy way to evaluatedeposit, provided lithology is understood

The closer values are to litho-minimums, the less the chancesof economic HC extractionLow mobility values also indicate low permeability, w/obimodal poresHigher values indicate higher effective porosity

Watch for chalk & silt porosity types as they have higher mins

Rocks with


11/13

movable HC

36 wells W. Latvia

bbl/acft bbl/acft200 235 max

94 131 avg60 90 std

36 nIX LS clean

Upper Ordovician Zone, Clean Carbonate, Western Latvia

Indication in 36 wells: this zone is a Cap Rock, typically


12/13

Well J-E6

Horner Analysis CompareDanish OPA/core

t, m 10 0.62

por % 11 17.4

k, md 2.5 40.5Horner gives md-m

Geol. Factors = thicknesscores show ~1m sucrosic LS

Indications are: oil flow is from thin lower sucrosic LS/Dolo


13/13

Thanks for hearing my considerations. A more detailed

Discussion is available by email request.

[email protected]

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AAG Presention 58400 r2