Longitudinal Reservoir Evaluation Technique for Tight Oil Reservoirs

Table 3

Longitudinal evaluation interval of tight reservoirs.

Classification interval	Throat radius (μm)	Movable fluids saturation (%)	Starting pressure gradient (MPa/m)	Clay minerals (%)	Comprehensive evaluation
I	0.6–0.8	60–75	0–0.3	0–5.0	>5.0
II	0.4–0.6	45–60	0.3–0.6	5.0–10.0	3.5–5.0
III	0.2–0.4	30–45	0.6–0.9	10.0–15.0	1.5–3.5
IV	0–0.2	15–30	0.9–1.2	15.0–20.0	0–1.5