American Oil and Gas Reporter - January 2017 - 65

Shale Resource Science
2), while toe-up/toe-down orientation is
a secondary variable when grouped into
smaller groupings of similar TVD ranges.
In the analysis, average lateral TVD
was found to be a primary variable affecting well performance. Secondary variables such as the impact of completion
parameters on well productivity became

evident when grouped into bins. TVDs
vary across the core Cana Woodford
(along with the three groupings used for
data binning) because the Woodford play
trends deeper as it moves from the northeast to the southwest.
Along with TVD variations, fluid types
in the reservoir also change. Deeper sec-

FIGURE 3
Average Cumulative Production versus Toe-Up/Toe-Down
554k

Color by:

550k
500k

Toe-Up

400k

750k
650k

Middle TVD

Toe-Down
Toe-Up

600k

424k

729k

Color by:

700k

Shallow TVD

Toe-Down

450k

550k
500k

350k

400k

255k

250k
200k
150k
100k

64k

54k

50k
0k

0
1
Avg/PRD_GAS CUM
(30 Days)

125k

105k

360k

350k
300k

277k

250k

173k

148k

460k

450k

311k

300k

100k

0
1
Avg/PRD_GAS CUM
(60 Days)

0
1
Avg/PRD_GAS CUM
(90 Days)

0
1
Avg/PRD_GAS CUM
(180 Days)

Color by:

0
1
Avg/PRD_GAS CUM
(30 Days)

600k

823k

0
1
Avg/PRD_GAS CUM
(90 Days)

0
1
Avg/PRD_GAS CUM
(180 Days)

0
1
Avg/PRD_GAS CUM
(365 Days)

722k

519k
405k

400k
300k

0k

0
1
Avg/PRD_GAS CUM
(60 Days)

Deep TVD

500k

100k

121k

91k

Toe-Down
Toe-Up

700k

200k

101k

55k

50k
0k

0
1
Avg/PRD_GAS CUM
(365 Days)

205k

136k

200k
150k

800k

193k
110k

251k

218k

306k

113k

0
1
Avg/PRD_GAS CUM
(30 Days)

0
1
Avg/PRD_GAS CUM
(60 Days)

0
1
Avg/PRD_GAS CUM
(90 Days)

Toe-Up/Down from Inclination

0
1
Avg/PRD_GAS CUM
(180 Days)

0
1
Avg/PRD_GAS CUM
(365 Days)

FIGURE 4A

Color by:

Toe-Down
Toe-Up

2.6k
2.4k
2.2k
2.0k
1.8k
1.6k
1.4k

-300

-200

7.5

-100
0
100
TVD Change (+ve down)

200

Toe-Down
Toe-Up

5.5
4.5
3.5
-300

-200

-100
0
100
TVD Change (+ve down)

800k
750k
700k

Color by:

Toe-Down
Toe-Up

650k
600k
550k
500k
450k
400k
350k

-300

-200

29k

Color by:

6.5

2.5

PRD_GAS IP (365 Day AVG)

3.0k
2.8k

200

RES_A square root of k

PRD_GAS IP (90 Day AVG)

Shallow TVD Data Bin

RES_GAS EUR (MMcf)

amount of uncertainty within the analysis.
The recommended dataset for this type
of analysis includes, but is not limited to:
* Wellbore descriptors (e.g., average
TVDs);
* Production metrics (e.g., cumulative
oil and gas);
* Geologic parameters (e.g., rock
properties, percentage in zone);
* Completion parameters (e.g.,
amount of proppant pumped); and
* Reservoir parameters (e.g., EURs).
It is important that the area being
studied is well defined before all appropriate data are collected. This will help
to ensure some geologic and reservoir
consistency across the area of interest.
Once all the information is organized
into a database, data visualization and
analytics software such as TIBCO's Spotfire® can be used to quickly look for
trends in well performance.
The second step in the workflow is to
identify primary and secondary variables.
Primary variables are those derived from
the entire dataset and exhibit strong statistical
correlations with well performance metrics.
Secondary variables are derived from primary dataset trends that display strong statistical correlations across the entire dataset
only when grouped into smaller bins.
Isolating variables to determine the
greatest impacts on well performance is
key for this type of analysis. The first
step in looking for well performance drivers is to identify the primary variables.
Care was taken to ensure primary variables
were not influencing trends seen in secondary variables.
All variables were cross-plotted against
well performance metrics such as 30- to
365-day gas cumulative production and
EURs to identify the strongest correlations
through linear regression, where the variables that exhibit the highest R2 values
from the regression analysis become primary variables. The results show that the
average TVD of the lateral is the primary
variable influencing gas production performance in the Cana Woodford (Figure

-100
0
100
TVD Change (+ve down)

200

Color by:

27k

Toe-Down
Toe-Up

25k
23k
21k
19k
17k
15k
13k

-300

-200

-100
0
100
TVD Change (+ve down)

200

JANUARY 2017 65
American Oil and Gas Reporter - January 2017

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