American Oil and Gas Reporter - September 2020 - 43

pages 40-47_Layout 1 9/18/2020 3:34 PM Page 43

WellFracturing: Diagnostics
FIGURE 1B
Surface Pressure Signal Magnitudes and Characteristics from BC7H After Drill-Out
1H

BP

1H

BC

Job size cut 30%

2H

BC

Same completion design stage group

2H

BP

H

BC7

H

BC6

H

BC4

H

BC5

Fluid migration responses

3H

BC

Direct fluid responses

or an understimulated stage.
Figure 1A shows the signals as classified from the child wells received at
BP1H while fracturing BC1H and BC2H.
Only three poroelastic responses were
observed. The remaining signals were
either fluid migration or direct communication. The lack of poroelastic responses,
and the consistency of fluid migration
and direct fluid communication, indicated
that fluid from the nearby child wells
was moving toward the parent well, even
with a far-field diverter applied as part of
the completion design.
The fracture network in the reservoir
was completely full of fluid because of
all the fractures being created in the same
area. Therefore, almost no pressure signals
were exclusively driven by rock compression (poroelastic response). Almost
all parent well communication was influenced by the fluid being pushed around

ates an instantaneous pressure increase
and a significant pressure buildup trend
followed by pressure leak-off at the end
of the stage;
· Fluid migration, identified by a
gradual pressure increase during treatment
and the following shut-in period, followed
by gradual decrease as excess pore-pressure dissipates into the reservoir and fracture system;
· Stress shadowing (poroelastic response), characterized by tensile and/or
compressive pressure changes resulting
from progressive growth of the dominant
hydraulic fracture in the child treatment
stage and an immediate elastic springback "shadow" at the end of the stage;
and
· No observable signal, which can
be the result of a large horizontal distance
between wells, but also can indicate complete pressure isolation between benches

by completion pressures interacting with
this fracture network.
Fracture Sequences
Given the results, the operator wanted
to test whether the fracture sequence and
the controllable stress barrier conditions
could significantly impact the communication between BP1H and BC1H. The
steps for the fracture sequences and data
acquisition plan for BC1H, BC2H and
BC3H were (Figure 2):
· Establishing the first pressure-based
fracture map monitor (surface pressure
gauge) after fracturing BC2H stage 1,
then two-well zippering between BC3H
and BC1H until BC1H stage 10. The toe
of BC2H monitored the toe portion of
BC1H (blue in Figure 2).
· Establishing the second pressurebased fracture map monitor on the BC1H
after fracturing stage 10, then two-well

FIGURE 2

8
7
6
5
4
3
2
1

12
11
10
9

30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13

36
35
34
33
32
31

148
146
144
142
140
138
136
113
111
109
107
105
103
101
99
97
95
93
91
89
87
85
83
81
79
77
75
73
71
69
67
65
63
61
59
57
55
53
51
49
47
45
43
41
22
20
18
16
14
12
10
8
6
4
54
53
52
51
50
49
48
47
46

45
44
43
42
41
40
39
38
37

154
152
150

8
7
6
5
4
3
2
1

12
11
10
9

30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13

36
35
34
33
32
31

100
98
96
94
92
90
88
86
84
82
80
78
76
74
72
70
68
66
64
62
60
58
56
54
52
50
48
46
44
42
40
38
36
34
32
30
28
26
24
2

45
44
43
42
41
40
39
38
37

54
53
52
51
50
49
48
47
46

106
104
102

40

BC3H

128
126
124
122
120
118
116
114
112
110
108

38
39

141

143
145
147
149
151
153
155
57
56
55

BC2H

134
132
130

31
32
33
34
35
36
37

129
131
133
135
137
139
29
30

127

127

129
131
133
135
137
139
24
25
26
27
28

23

117
119
121
123
125

37
39
115

17
18
19
20
21
22

29
31
33
35

21
23
25
27

10
11
12
13
14
15
16

2
3
4
5
6
7
8
9

1

3
5
7
9
11
13
15
17
19

125

BC1H

57
56
55

Data Acquistion Plan and Fracture Sequence for BC1H, BC2H and BC3H

SEPTEMBER 2020 43
American Oil and Gas Reporter - September 2020

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