Abstract:

In order to suternarrviondtions, it is necessary that water saturation establishment in cores must be any saturation desired and insure water uniformly dispersed, the pore geometry and component of cores unchanged. At present, there are several mainly methods to establish water saturation such as drying method, centrifuge method and displacement method. Seeing that tight gas sands has tight lithologic character and ultra-low water saturation, it is difficult or impracticable that water saturation estaedghs thse methods is less than irreducible water saturation. The paper puts forward a new method of establishing water saturation called spontaneous imbibition method, it can be used to establish water saturation in tight sandstones and has been proved by experiments to be feasible.

Key words: tight sands, core analysis, water saturation, pontaneous imbibitions