Table 2 Identification criteria for large-scale fracture filling.

From: Identification of fractures in tight-oil reservoirs: a case study of the Da'anzhai member in the central Sichuan Basin, SW China

Large-scale fractures

GR (API)

AC (μs/ft)

RT (Ω·m)

Non-filled

10–30

50–55

800–2000

Mud-filled

 > 20

48–52

100–2000

Calcite-filled

 < 21

49–65

1000–10,000