... Type-2 naturally fractured reservoirs, where matrix porosity is much greater than fracture porosity, as the reservoir pressure drops the matrix porosity decreases in favor of fracture porosity 9. ... Nelson, R.: “Geologic Analysis of Naturally Fractured Reservoirs”. Gulf Professional Publishing, 2nd Edition. 2001 2. Ershaghi, I.: “Evaluation of Naturally Fractured Reservoirs”. IHRDC, PE 509, ... observed because of unique permeability trends. PROPERTIES OF MATRIX BLOCKS AND FRACTURES A naturally fractured reservoir is composed of a heterogeneous system of vugs, fractures, and matrix...