Geofluids / 2019 / Article / Tab 3

Research Article

Experimental Investigation on Propagation Behavior of Hydraulic Fractures in Coal Seam during Refracturing

Table 3

Experimental parameters and results of refracturing in coal.

Specimen number
(MPa)
Breakdown pressure
(MPa)
Fracture geometry
Initial fracturingRefracturing

129.284.54Initial HF connected with cleats, no new HFs were formed
224.142.97Initial HF was initiated from cleats, no new HFs were formed
325.233.15An initial HF connected with cleats and BPs, no new HFs were formed
448.8611.30A new HF was perpendicular to the initial HF
5423.0316.40New branches propagated along cleats
648.475.36New HFs connected with cleats
7615.0213.65New HFs were perpendicular to the initial HF
8612.687.34A simple initial HF connected with cleats, no new HFs were formed
984.461.82A HF network consisting of initial HFs and cleats, no new HFs were formed
10813.588.74A initial HF connected with cleats and two BPs, no new HFs were formed

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