Tight Precambrian and Paleozoic Reservoirs in the Light of Petrophysical Analysis

Standard laboratory investigations turned out to be not sufficient for the Precambrian and Paleozoic rocks from great depths. Especially low porosity and permeability were difficult to be accurately determined. Combination of several known methods as: NMR investigations and mercury porosimetry and micro-tomography (micro-CT) showed new aspects in investigations of such rocks, important as tight gas reservoirs. Improved methodology in NMR processing by detailed cut off determination enabled more precise Free Fluid Index determination. Computerized mercury porosimetry results visualization and processing provide new utility value as automatically determined Swanson parameter correlated with petrophysical properties. Micro-CT enriched the image of porous space in qualitative and quantitative ways.