Page 337 - Fundamentals of Gas Shale Reservoirs

RESOURCE EVALUATION OF SHALE GAS PLAYS 317
gas resources per section since it has the largest net pay matrix, while a small value indicates that flow between the
thickness. The Marcellus Shale has a high RF due to a high media is restricted. The Eagle Ford Shale has a high RF due
–6
value of interporosity flow coefficient (λ = 9 × 10 ) to its high reservoir pressure.
(Fig. 14.22). High value of interporosity flow coefficient Table 14.13, constructed for the four major shale gas plays,
means that fluids flow easily between the fracture and provides a concise summary of these resource assessments.

100
Barnett (lognormal)
90 Haynesville (lognormal)

80 Eagle Ford (pearson5)
Marcellus (pearson5)
70
60
Percentile 50

40
30
20

10
0
0 20 40 60 80 100
Recovery factor (%)
FIGURE 14.22 Comparison between probabilistic distributions of recovery factor (RF) for the four shale gas plays in the United States
(Adapted from Dong et al., 2014).

TAbLE 14.13 Summary of resource assessment for four target shale gas plays in the United States

Parameter Barnett Eagle ford Marcellus Haynesville
Area, Acres 3,200,000 3,000,000 15,000,000 5,760,000
Well spacing, acre 111 147 104 124
Number of wells 28,828 20,407 144,230 46,451
Distribution of OGIP Log‐logistic Log‐logistic Pearson 5 Lognormal
OGIP (P90), Bcf/well 8.4 7.5 3.8 22.0
OGIP (P50), Bcf/well 12.2 13.6 9.6 40.0
OGIP (P10), Bcf/well 17.8 25.3 20.8 68.0
Distribution of technically Lognormal InvGauss InvGauss Lognormal
recoverable resources (TRR)
TRR (P90), Bcf/well 1.1 2.3 1.5 3.1
TRR (P50), Bcf/well 2.2 4.4 3.7 7.1
TRR (P10), Bcf/well 4.5 8.5 8.5 15.2
Distribution of RF Lognormal Pearson 5 Pearson 5 Lognormal
RF (P90), % 10 25 29 10
RF (P50), % 18 31 39 18
RF (P10), % 35 40 52 33
OGIP (P90), Bcf/section 48 33 23 114
OGIP (P50), Bcf/section 70 59 59 206
OGIP (P10), Bcf/section 103 110 128 351
TRR (P90), Bcf/section 6 10 9 16
TRR (P50), Bcf/section 13 19 23 37
TRR (P10), Bcf/section 26 37 52 78
OGIP in Dong study (P50), Tcf 352 278 1385 1858
TRR in Dong study (P50), Tcf 63 90 534 330