Petrophysical, Mechanical, and Recovery Factor Analysis

Saeed Zargari, Piya Dechongkit, Manika Prasad 05/03/2012

Bakken Consortium Meeting Colorado School of Mines

5/3/2012 1

Motivation Methodology

Outline (Petrophysical and Mechanical)

5/3/2012 2

• Building Rock Physics Models – Texture – Elastic Properties – Heterogeneity

• Spatial detection of sweet spots/maximum hydrocarbon generation – Challenges: Laminated texture/Oriented minerals/Induced Fractures (Vernik

and Nur, 1992)

• Study change in petrophysical properties with maturation

Motivations

5/3/2012 3

y = 30.436e-4.94x R² = 0.881

0

10

20

30

40

0.0 0.1 0.2 0.3 0.4 0.5

C66

(MPa

)

Porosity + 0.4*Kerogen Content

BAKKEN BAZHENOVNIOBRARA WOODFORD

Good correlation between porosity and elastic modulus by accounting for pore-filling kerogen.

KC_Φ = Φ + 0.4 KC

Data from Vernik and Liu, 1997 , Prasad et. al 2010 Schmoker and Hester (1983) TOC

Form

atio

n D

ensi

ty

Density-Modulus–Porosity–Kerogen Content

5/3/2012 4

8 μm

Pyrolized Bakken Sample 7221ft

5/3/2012 5

Dr. Brian Gorman

Acoustic Scans- Bakken Shale

62 µm

294 319

122 175

Prasad et al., 2005 5/3/2012 6

Nanoindentation Modulus

50

37

107

88

36

45

46

53

59

70

58

55

59

60

55

37

55

TOPO COMPO

5/3/2012 7

Bakken Shale 11246 ft

Modulus of Softer Portion of the OR Rock

5/3/2012 8

TOC

Modulus of Softer Portion

Kerogen+Clays+ Minerals

Kerogen+Clays+ Bitumen+Minerals

Future Work

5/3/2012 9

• Building 3-D model of mechanical properties in

organic rich shales

• Investigating porosity generation in kerogen (Mechanical/Chemical)

We Need SMALL pieces of Samples, preferably from oil-gas transition zone

Objective Methodology Sensitivity Analysis Recovery Factor-EUR Results

Outline (Recover Factor Analysis)

5/3/2012 10

• Calculate RF of Bakken System, Williston Basin by using MBE

• Determine the range (distribution) of RF (from Monte Carlo simulation)

• Identify the most effective parameters on RF

• Determine well-by-well Expected Ultimate Recovery (EUR)

• Calculate Original Oil In Place (OOIP) of Antelope, Parshall, Sanish fields

Total Active Non-activeAntelope Sanish Vertical well December(1953 52 13 39

Sanish Bakken Horizontal well April(2006 135 135 -

Parshall Bakken Horizontal well May(2006 182 179 3

Number of wellsField

Timing of first productionPool

Type of completion

Objective

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1. Deterministic RF from MBE

2. Probabilistic RF from MBE

3. Sensitivity analysis for the input parameters

4. EUR with Decline Curve Analysis (DCA)

5. OOIP = EUR / RF

Methodology

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4000 4500 5000 5500 6000 6500 7000 75000

500

1000

1500

2000

2500Initial Pressure (psi)

P initial

170 180 190 200 210 220 230 240 2500

500

1000

1500

2000

2500Reservoir Temperature (F)

T reservoir

1600 1800 2000 2200 2400 2600 2800 30000

500

1000

1500

2000

2500Bubble-point Pressure (psi)

P bubble-point

500 600 700 800 900 1000 1100 12000

200

400

600

800

1000

1200

1400

1600

1800

2000Abandonment Pressure (psi)

P abandonment

100,000 samples

Oil, gas and rock

properties (e.g. Bo, Bt, Rso, etc)

using correlations

RF by MBE

0.06 0.07 0.08 0.09 0.1 0.11 0.120

500

1000

1500

2000

2500

3000

3500Recovery Factor at Abandonment Pressure

RF at P abandonment

100,000 values of RF

Probabilistic (by Monte Carlo simulation)

Parameters Min MaxInitial reservoir pressure (psia) 4,060 7,325Reservoir temperature (F) 175 250Bubble-point pressure (psia) 1,730 2,900Abandonment pressure (psia) 500 1,200Oil API gravity (degree API) 39 45Gas specific gravity 0.77 0.88Initial water saturation (decimal) 0.20 0.50Water salinity (ppm) 2,000 471,000Porosity (decimal) 0.01 0.16

*

Distribution of primary parameter (Pi, T, Pb, etc)

Methodology (cont.) – RF calculation

5/3/2012 13

RF = 9.15% (base case result)

10% from base case±

11 – 12 % RF change

6 – 7% RF change Worst case

Best case

14

Results (cont.) – Sensitivity of RF

5/3/2012

Antelope Sanish

Parshall

Probabilistic results of

the RF

0.20

0.20

0.11

5/3/2012 15

0

1000

2000

3000

4000

5000

6000

7000

0

2000

4000

6000

8000

10000

12000

14000

Sep-65 Apr-66 Oct-66 May-67 Nov-67 Jun-68 Dec-68

Rp a

nd R

so (s

cf/b

bl)

Oil

mon

thly

pro

duct

ion

(bbl

s)

Date

Oil monthly productionCumulative GOR, RpMonthly GOR, Rso

Rsoi

Bubble point

Antelope field, vertical well, well# 4018 Rp-Rsoi ~1000 - 2000

Sanish field, well# 17022, Rp-Rsoi ~100 - 200

Parshall field, well# 16346, Rp-Rsoi ~70 - 100

RF results (Rp – Rsoi)

5/3/2012 16

05

10152025303540

EUR Statistics-Antelope Field

05

10152025303540

EUR Statistics-Sanish Field

05

10152025303540

EUR Statistics-Parshal Field

Num

ber o

f Wel

ls

Num

ber o

f Wel

ls

Num

ber o

f Wel

ls

EUR (Mbbl)

EUR (Mbbl) EUR (Mbbl)

Vertical Wells

Horizontal Wells Horizontal Wells

EUR statistic results

5/3/2012 17

0

500

1000

1500

2000

2500

3000

0 2 4 6 8 10 12

EUR

(Mbb

l)

Numbers of stages of hydraulic fracturing

Theloy (2011)

EUR and #stages of HF in Sanish field

Results(cont.)–EUR vs. hydraulic fracturing

5/3/2012 18

Sanish

Parshall

Sanish

Parshall

EUR

val

ues

* GIS

map

ser

ver i

n N

DIC

web

site

*

Results(cont.)–EUR of Sanish & Parshall fields

5/3/2012 19

N

)(1 wiHCPV h Sφ= −

* Simenson (2010)

*

Results(cont.)–EUR of Sanish & Parshall fields

5/3/2012 20

0

4000

8000

12000

16000

0 4000 8000 12000 16000

OOIP

from

EUR

and

RF ra

tio (M

bbl)

Volumetric OOIP (Mbbl)

drainage area = 640 acres

The comparison between OOIP from the EUR and the RF ratio and the volumetric OOIP

5/3/2012 21

1. The RF of Parshall (16%) and Sanish (15%) fields are higher than that of the Antelope (9%)

2. Pressure maintenance is key for high EUR and RF

3. The high EUR area is located where high HPV exists

4. Drainage area might be much less than the current well spacing of 640 acres – target for infill drilling

Conclusion

5/3/2012 22

Acknowledgement We would like to acknowledge:

• OCLASSH Consortium for financially supporting this project • Financial support of Chevron Thailand Business Unit (for P. Dechongkit's

education) • OCLASSH and Center for Rock Abuse members for discussions • US DOE (Award# DE-NT0005672) and Norwegian Research Council for initial

support • Dr. Corinne Packard , Mr Grant Klafehn and Mr. Masoud Hashemi for their help in

performing Nanoindentation tests • Thanks to Dr. Brian Gorman and Dr. John Chandler for help with FESEM images • Dr. Quinn Passey for his valuable comments • Craig Van Kirk, Stephen Sonnenberg (CSM), and Chet Ozgen (NITEC LLC Company)

for valuable input, guidance and discussions • Andrea Simenson (Discovery Group), Cosima Theloy, Ryan Vera, Baoqing Xu, and

John Akinboyewa (CSM) for their input, discussions, and comments 5/3/2012 23