Bulk volume irreducible fluid

BVI is bulk volume irreducible fluids (derived from NMR)... 

If the NMR response is capable of estimating the pore size distribution, then it also has the potential to estimate the fraction of the pore space that is capable of being occupied by the hydrocarbon and the remaining fraction that will only be occupied by water. The Free Fluid Index (FFI) is an estimate of the amount of potential hydrocarbons in the rock when saturated to a given capillary pressure. It is expressed as a fraction of the rock bulk volume. The Bulk Volume Irreducible (BVI) is the fraction of the rock bulk volume that will be occupied by water at the same capillary pressure. The fraction of the rock pore volume that will only be occupied by water is called the irreducible water saturation (Siwr = BVI/cj>). The amount of water that is irreducible is a function of the driving force to displace water, i.e., the capillary pressure. Usually the specified driving force is an air-water capillary pressure of 0.69 MPa (100 psi). 

BVI versus BVM the BVl (bulk volume of irreducible fluid) and BVM (bulk volume of movable fluid) can be estimated by partitioning the T2 distribution and can also be interpreted as pore size distribution" (Chen and Georgi, 1997 Kenyon, 1992 Straley et al., 1995). 

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