Low field Nuclear Magnetic Resonance was combined with high speed centrifugal experiments to study movable fluids and T

2

cutoff values of marine shale in South China.The experiments reveal the importance of establishing water saturated state and irreducible water state for the calculation of movable fluids.For marine shale from South China

the optimum pressure for establishing water saturated state is 12MPa

and the optimum centrifugal force for establishing irreducible water state is 2.76MPa.The T

2

cutoff values range between 1.07ms and 3.22ms

averaging at 1.8ms

significantly less than that of tight sandstone.Therefore

using empirical value (13ms) for the calculation of movable fluids may result in great error.To deal with the problem

we integrated the T

2

spectrums of both saturated water state and irreducible water state to calculate movable fluid saturation.The result ranges between 23.19% and 30.84% (averaging at 27.28%)

indicating high irreducible water saturation and ultra-low water saturation.we also converted the NMR T

2

spectrum into pore size distribution

revealing the pore radius of shale to be within 20 and 200 nm range.