Ultra-low Permeability Rocks: Laboratory Measurement and Low Pressure Gradient Analysis

Abstract

The flow curve of standard brine (salinity: 80 g/L), kerosene, and light crude oil in the ultra-low permeability core plugs with full diameter drilled from the Erdos basin have been measured through fully automatic flooding system-AFS300 provided by Core Lab of America (Houston, TX) under low pressure gradient (0.005–0.3 MPa/m) with the steady-state approach. The experiments indicated that the flow rate of the downstream of the core plug increases linearly as the increase of the pressure gradient and nonlinearity was not observed. In a way, the experiments indicated that the Darcy law holds in the ultra-low permeability in the experiment and the interaction force between the porous surface of the cores and the brine, kerosene, and light crude oil cannot cause nonlinearity.

Keywords:

• Darcy's law
• linear flow
• saturated flow
• threshold pressure gradient
• ultra-low permeability