Method of determining the porosity and irreducible water saturation of a

Abstract

The irreducible water saturation profile across the length of a core sample of coal is determined from four series of X-ray attenuation measurements made over the length of the core sample. The X-ray attenuation measurements are made while the core sample is at a pressure simulating a formation overburden pressure. The first series of X-ray attenuation measurements are made while the core sample is saturated with distilled water or formation brine. The distilled water or formation brine is then displaced with humidified, inert, substantially nonadsorbing gas and a second series of X-ray attenuation measurements are made. The core sample is then saturated with an aqueous sodium iodide solution and a third series of X-ray attenuation measurements are made. The aqueous sodium iodide solution is then displaced with a humidified, inert, substantially nonadsorbing gas and a fourth series of X-ray attenuation measurements are made.