Quantitative Prediction of Low-Permeability Sandstone Grain Size Based on Conventional Logging Data by Deep Neural Network-Based BP Algorithm

Table 5

Grain size interval of different sedimentary microfacies.

	Category	Cumulative probability	Main granularity interval (Φ)
Submerged distributary channel	I	>85%	0 ~ 3.5
	II	>90%	0 ~ 4
	III	>60%	3 ~ 4
	IV	>60%	0 ~ 2
Estuary dam	I	>70%	1 ~ 4
	II	>60%	1 ~ 2.5
	III	>70%	1 ~ 2.5