American Oil and Gas Reporter - December 2015 - 56

page 52-63_Layout 1 12/2/2015 10:52 AM Page 56

SpecialReport: Well Stimulation & Completion Technology
FIGURE 3
Zone-Wise Correlations Between Vclay and Brittleness Index (A),
Young's Modulus (B) and Closure Stress (C)
Brittleness
Index

WFMP B Bench: Brittleness vs Vclay

A

90
y=-74.176x + 83.908
R2 = 0.8387
80
70

Brittleness
Index
-66
-57

60
50

40

30
0.00

Young's
Modulus
(Gpa)

0.10

0.20

Vclay (v/v)

0.40

0.50

0.60

WFMP B Bench: Young's Modulus vs Vclay

B

12,000,000
y=-1E+07x + -1E+07
R2 = 0.8592

10,000,000

0.70

8,000,000

Young's
Modulus
(Gpa)
-5.5e+006
-4.5e+006

6,000,000

4,000,000
2,000,000

0
0.00

Stress
(psi)

0.10

0.20

Vclay (v/v)

0.40

0.50

0.60

C

8,000
y=-12,510x2 - 11,654x + 7,815.7
R2 = 0.863

7,500

0.70

7,000

Stress
(psi)
-6,200

6,500

-5,700

6,000
5,500
5,000
4,500
4,000
0.00

0.10

0.20

Vclay (v/v)

0.40

0.50

0.60

0.70

FIGURE 4
Vclay Pseudo Lateral Log Extrapolated
From 3-D Seismic Lengthwise along the Neal 345H

56 THE AMERICAN OIL & GAS REPORTER

tical well. The cross plots showed strong
correlations, resulting in linear transform
functions that were used to create the mineralogical and geomechanical seismic
volumes of each property.
Zone-wise attribute maps of the correlations were generated to enable the direct
extrapolation of properties lengthwise
along the wellbores in creating seismic
pseudo-lateral logs. Figure 3 shows strong
correlations among Vclay and brittleness
index, Young's modulus, and closure
stress. The linearity of the geomechanical
properties confirms that replacing Vclay
with Vcal results in greater fracability.
The extrapolated pseudo-Vclay log
created from the workflow (Figure 4, with
the arrows indicating minimal Vclay for
optimal fracture stimulation) was followed by reformatting a full suite of logs
to a log ASCII standard file for inputting
into fracture modeling software. This enabled surface seismic rock properties
nearest the lateral (where microseismic and
completion data were acquired) to be
modeled versus data interpolated significant distances from the study area.
A more detailed and unique stage-bystage analysis using the surface seismic impedance could be integrated now with
completion data, microseismic data, and
fracture models for "smart" frac analysis
to determine optimal stimulation and
completion parameters on future wells.
Microseismic Interpretation
The Neal 346AH was landed in the
Wolfcamp A bench and treated first, followed by the 345H and 344H wells in the
Wolfcamp B. As part of the simultaneous
zipper fracturing process, an identical
hydraulic fracturing treatment pump
schedule was designed for all three laterals, using geometrical completion spacing.
The pump schedule consisted of slickwater with 100-mesh sand and 40/70-mesh
white sand.
Treatment parameters were adjusted
using real-time microseismic to control excessive height growth. The main concern
was completing stages 4 and onward toward
the heel of the wells-particularly the deeper Wolfcamp B wells-since they were
aligned with the shallower Wolfcamp A
stages and potentially could lead to interference issues between developed fractures.
The first 12 toe-ward stages of each of
the laterals were monitored using a 16-receiver downhole array deployed in the vertical section of the Wooley 5 No. 6 monitor well. The rest of the stages were not
American Oil and Gas Reporter - December 2015

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