RESOURCE ASSESSMENT
Michael Hohn, Susan Pool, and Jessica Moore
West Virginia Geological & Economic Survey
Background
Approaches to estimating hydrocarbon
volumes for continuous unconventional
reservoirs:
• Use production data to estimate
recoverable resources directly
• Use geologic data to estimate original
hydrocarbons-in-place from which
recoverable resources can be determined
Background
• All hydrocarbon that
could be produced
(varies):
– Technically recoverable (TRR)-function of geology and
technology
– Economically recoverable
(ERR)--function of geology,
technology, and economics
• All the hydrocarbon
that exists (fixed):
– Original hydrocarbon-in-place
(OHIP)--function of geology
Modified from Boswell
REMAINING RESOURCES
Assessment of Utica Shale Play
Remaining Resources
Methodology
• Probability-based U.S. Geological Survey
method
• Uses distributions for total assessment
unit area, areas of sweet spots, EUR, and
success rates
• Excludes wells already producing
• Monte Carlo sampling of distributions for
mean, median, 5%, 95% values for total
resource
Steps
• Definition of total assessment units
• Delineation of minimum, median,
maximum area of sweet spots
• Decline curve analysis for determining
estimated ultimate recoveries
• Success ratios
• Drainage areas
Assessment Units
Producing Oil Wells
Condensate/NGL Production
Producing Gas Wells
Definition of Assessment Units:
Thermal Maturity
Gas
Prone
Overmature
Oil Prone
Wet Gas
Definition of Assessment Units:
Oil Sweet Spot
Definition of Assessment Units:
Oil Sweet Spot
Definition of Assessment Units:
Wet Gas Sweet Spot
Assessment Units and Sweet Spots
Oil Sweet
Spot
Maximum
Wet Gas
Sweet
Spot
Maximum
Dry Gas
Sweet
Spot
Maximum
Oil Sweet
Spot
Minimum
Dry Gas
Sweet
Spot
Minimum
Wet Gas
Sweet
Spot
Minimum
Estimated Ultimate Recovery
Estimated Ultimate Recovery
160,000
140,000
120,000
Barrels Oil
100,000
80,000
60,000
40,000
20,000
0
0
10
20
30
Months
40
50
Estimated Ultimate Recovery
160,000
140,000
120,000
Median 1 year
Barrels Oil
100,000
Median 2 years
80,000
Median 3 years
60,000
Median 4 years
40,000
Median
20,000
0
0
10
20
30
Months
40
50
EUR Model
350,000
300,000
250,000
Median 1 year
Barrels Oil
Median 2 years
200,000
Median 3 years
Median 4 years
150,000
Median
100,000
Minimum EUR
model
Median EUR Model
Maximum EUR
Model
50,000
0
0
20
40
60
Months
80
100
120
EUR Distributions
Oil AU (MMbo)
Min
Med
Max
Sweet Spot
0.022
0.199
0.628
Non Sweet Spot
0.002
0.022
0.049
Wet Gas AU (Bcf)
Min
Med
Max
Sweet Spot
0.64
5.76
18.84
Non Sweet Spot
0.20
0.64
1.19
Gas AU (Bcf)
Min
Med
Max
Sweet Spot
0.19
7.09
30.37
Non Sweet Spot
0.039
0.19
0.32
Success Rates
Oil AU (%)
Min
Med
Max
Sweet Spot
90
95
99
Non Sweet Spot
1
3
5
Wet Gas AU (%)
Min
Med
Max
90
95
99
5
10
40
Gas AU (%)
Min
Med
Max
Sweet Spot
90
95
99
5
10
40
Sweet Spot
Non Sweet Spot
Non Sweet Spot
Results
OIL MMbo
Oil Assessment
Unit
F95
Sweet Spot
NonSweet Spot
Total
Wet Gas
Assessment Unit F95
F50
Gas Bcf
F5
Mean
F95
3,744
1,908
2,231
6,636
17,722
7,949
23
49
91
52
69
191
446
216
791
1,728
3,788
1,960
2,370
6,858
17,960
8,165
OIL MMbo
F50
F5
Gas Bcf
Mean
Total
NonSweet Spot
Total
Mean
1,677
F95
F50
F5
Mean
49,601
106,550
55,980
99
379
1,023
447
24,484
50,037
106,852
56,427
OIL MMbo
F50
F5
23,840
NonSweet Spot
Sweet Spot
F5
733
Sweet Spot
Gas Assessment
Unit
F95
F50
Gas Bcf
Mean
F95
F50
220,473
2,862
228,478
F5
Mean
590,680 1,542,873
6,584
710,341
13,835
7,238
598,026 1,549,586
717,579
ORIGINAL IN-PLACE
RESOURCES
Assessment of Utica Shale Play
In-Place Resources using
Volumetric Approach
Purpose
• Estimate original hydrocarbon-in-place
volumes for selected stratigraphic units
• Determine general overall hydrocarbon
distribution
• Examine key parameters that may impact
hydrocarbon distribution
Methodology and Data
Use geologic data and volumetric approach
to estimate total original hydrocarbon-inplace (OHIP):
OHIP = Free + Adsorbed
Methodology and Data
Use geologic data and volumetric approach
to estimate total original hydrocarbon-inplace (OHIP):
OHIP = Free + Adsorbed
Free Hydrocarbon-in-Place
OGIPfree = (feff * (1-Sw) * (1-Qnc) * Hfm * Ar * 4.346*10-5 ) / FVFg
OOIPfree = (feff * (1-Sw) * Hfm * Ar * 7758) / FVFo
Adsorbed Hydrocarbon-in-Place
OGIPadsorb = Gc * rfm * Hfm * Ar * 1.3597*10-6
?OOIPadsorb= S2 * 0.001 * rfm * Hfm * Ar * 7758
Methodology and Data
Hfm , rfm , f, and Sw
are derived from Utica Project well logs
with f and Sw adjusted for Vsh and Vker
TOC
is from Utica Project sample/well log data
Gc
is from publicly-available isotherms
given TOC and pressure
FVF
is derived from Utica Project well logs and other publicly-available data
given temperature, pressure, and gas compressibility
Methodology and Data
1. Identify and select wells meeting approach criteria
2. Examine stratigraphic picks and well log data
3. Select and extract well log data
4. Compile and derive additional required data
5. Process data and estimate volumes
6. Correct and refine data
Methodology and Data
Step 1—Identify and Select Wells
Searching for:
• Utica, Point Pleasant, Logana penetrations
• Top depth no less than 2,500 feet (initial); ~3,000 feet (final)
• Digital well logs with, at minimum,
gamma ray, bulk density/porosity, resistivity traces
• Vertical non-faulted wells
• Even geographic distribution
Methodology and Data
Step 1—Identify and Select Wells
Digital logs for wells with Utica, Point Pleasant, and/or Logana identified plus
top depth greater than 2500 feet
Methodology and Data
Step 1—Identify and Select Wells
Full suite digital logs for wells with Utica, Point Pleasant, and/or Logana identified plus
top depth greater than 2500 feet
Methodology and Data
Step 1—Identify and Select Wells
Full suite digital logs for wells with Utica, Point Pleasant, and/or Logana identified plus
top depth greater than 2500 feet
Note: Limited digital well log data
Methodology and Data
Step 1—Identify and Select Wells
Thermal maturity as determined from equivalent %Ro
•
Determined level
of maturity for
selected wells
based on
equivalent %Ro
map
•
Divided in-place
assessment into
gas and oil
regions
•
Assumed single
phase in each
hydrocarbon
region
Methodology and Data
Step 2—Examine Stratigraphic Picks and Logs
Example digital well log data with stratigraphic units identified;
used to review log availability through units plus assess log quality
Methodology and Data
Step 3—Select and Extract Log Data
Example digital well log data with stratigraphic units identified;
used to review log availability through units plus assess log quality
Log data:
• Gamma ray
• Density and porosity
• Resistivity
• Temperature
• TOC
Notes:
• Normalized
• Sample interval=0.5 feet
Methodology and Data
Step 4—Compile and Derive Additional Data
Including:
• Total Organic Carbon
• Pressure
• Volume of Shale
• Temperature
• Gas Content
Methodology and Data
Step 4—Compile and Derive Additional Data
Mean total organic carbon (%) for Utica Shale
as derived from Consortium analytical data
TOC
Methodology and Data
Step 4—Compile and Derive Additional Data
Mean total organic carbon (%) for Point Pleasant Formation
as derived from Consortium analytical data
TOC
Methodology and Data
Step 4—Compile and Derive Additional Data
Mean total organic carbon (%) for Logana Member of Trenton Limestone
as derived from Consortium analytical data
TOC
Methodology and Data
Step 4—Compile and Derive Additional Data
Had limited reservoir pressure data. From formation-specific well
data for WV and OH, Consortium partner input, and publiclyavailable data; assumed pressure gradients (psi/ft) of:
• 0.433 for NY and 0.6 for remaining area except...
• 0.5 in very small portion of southern NY
• 0.7 in small portion of north central PA
• 0.7-0.9 in small area including southwestern PA, northern WV
panhandle, and east central OH
Pressure
Methodology and Data
Step 4—Compile and Derive Additional Data
Corrected for volume of shale as extracted from:
• X-ray diffraction (XRD) data
• Maps from XRD data
• Gamma ray well logs plus XRD data
Volume of Shale
Methodology and Data
Step 4—Compile and Derive Additional Data
Temperature gradient
as derived from the National Geothermal Project data
Temperature
Methodology and Data
Step 4—Compile and Derive Additional Data
Gas content determined from publicly-available isotherms
given total organic carbon (TOC) and pressure
•
CH4 isotherm for various states
•
Isotherm used for OH given TOC and
pressure
•
Isotherm values from NY and OH
averaged for northwestern corner of PA
given TOC and pressure
Gas Content
•
CH4 isotherm for NY
•
Isotherm used for NY, majority of PA, and
WV given TOC and pressure
Advanced Resources International, Inc.
Methodology and Data
Step 5—Process Data and Estimate Volumes
a. Estimate effective porosity
b. Estimate water saturation
c.
Estimate formation volume factor
d. Estimate free hydrocarbon volumes
e. Estimate adsorbed hydrocarbon volumes
Methodology and Data
Step 5—Process Data and Estimate Volumes
Porosity Notes:
• Determined density porosity from bulk
density or used density porosity
• Used both density and neutron porosity if
available
• Corrected for Vsh as extracted from XRD
data, maps from XRD data, and gamma
ray well logs+XRD data
• Corrected for Vker as extracted from maps
assuming linear relationship between TOC
and Vker
Methodology and Data
Step 5—Process Data and Estimate Volumes
Water Saturation Notes:
• Used Simandoux equation
• Used A=1, M=1.7, and N=1.7
• Corrected for Vsh as extracted from XRD
data, maps from XRD data, and gamma
ray well logs+XRD data
• Corrected for Vker as extracted from maps
assuming linear relationship between TOC
and Vker
Methodology and Data
Step 5—Process Data and Estimate Volumes
Additional Notes:
• Used TOC from Utica Project analytical
data and maps rather than using TOC
from Passey method
Methodology and Data
Step 5—Process Data and Estimate Volumes
Preliminary summary results
Original In-Place Resources,
Average Volumes Per Unit Area
Stratigraphic Unit
Oil (MMbo/mi2)*
Gas (Bcf/mi2)*
Utica Shale
20.8
53.5
Point Pleasant
Formation
15.8
85.1
3.0
17.0
Logana Member of
Trenton Limestone
* = average volume per square mile in the sweet spot area; sweet spot area is as defined to estimate
remaining recoverable resources using the probabilistic (USGS-style) approach
Methodology and Data
Step 5—Process Data and Estimate Volumes
Utica Shale original in-place volumes per unit area,
preliminary summary results
DISCLAIMER: This map is a preliminary draft which reflects data and analyses current as of July 14, 2015.
The volumetric calculations and derivative maps will likely change as additional data become available and
techniques are refined. Users are cautioned that this map represents only a best estimate of trends given
limited available data and should not be used as a stand-alone product.
average volume per square mile in the sweet spot area; sweet spot area is as defined to estimate
remaining recoverable resources using the probabilistic (USGS-style) approach
Supplemental Slide 1
Methodology and Data
Step 5—Process Data and Estimate Volumes
Point Pleasant Formation original in-place volumes per unit area,
preliminary summary results
DISCLAIMER: This map is a preliminary draft which reflects data and analyses current as of July 14, 2015.
The volumetric calculations and derivative maps will likely change as additional data become available and
techniques are refined. Users are cautioned that this map represents only a best estimate of trends given
limited available data and should not be used as a stand-alone product.
average volume per square mile in the sweet spot area; sweet spot area is as defined to estimate
remaining recoverable resources using the probabilistic (USGS-style) approach
Supplemental Slide 2
Methodology and Data
Step 5—Process Data and Estimate Volumes
Logana Member of Trenton Limestone original in-place volumes per unit area,
preliminary summary results
DISCLAIMER: This map is a preliminary draft which reflects data and analyses current as of July 14, 2015.
The volumetric calculations and derivative maps will likely change as additional data become available and
techniques are refined. Users are cautioned that this map represents only a best estimate of trends given
limited available data and should not be used as a stand-alone product.
average volume per square mile in the sweet spot area; sweet spot area is as defined to estimate
remaining recoverable resources using the probabilistic (USGS-style) approach
Supplemental Slide 3
Methodology and Data
Step 5—Process Data and Estimate Volumes
Preliminary summary results
Original In-Place Resources,
Total Volumes
Stratigraphic Unit
Oil (MMbo)*
Gas (Bcf)*
Utica Shale
43,508
1,098,119
Point Pleasant
Formation
33,050
1,745,803
6,345
348,476
Logana Member of
Trenton Limestone
* = estimated volume in the sweet spot area; sweet spot area is as defined to estimate remaining
recoverable resources using the probabilistic (USGS-style) approach
Comparison of Results
Resources
Recoverable
Resources
Original In-Place
Resources
Current Recovery
Factors
Oil (MMbo)*
Gas (Bcf)*
2,611
889,972
82,903
3,192,398
3%
28%
* = estimated volume in the sweet spot area; sweet spot area is as defined to estimate remaining recoverable
resources using the probabilistic (USGS-style) approach
Issues
• Limited amount of full-suite well log data especially for
Pennsylvania and West Virginia
• Limited formation pressure data
• Limited core data for log-to-core calibration
Supplemental Slide 4
Potential Future Work
• Incorporate additional data from supplemental sources (e.g.
IHS)
• Incorporate additional data from wells with less than full
suites of log data
• Investigate additional data processing techniques
• Conduct sensitivity analysis
• Update EUR’s and sweet spots as play develops
Supplemental Slide 5