PetroChina Company Limited
Method for determining gas saturation of tight reservoir

Abstract:

The present invention a method for determining the gas saturation of a tight reservoir. The method comprises the steps of: determining the pore size distribution of the tight reservoir rock sample, and calculating the free water saturation; calculating the water-membrane water saturation; calculating the corner water saturation; calculating the gas saturation of the tight reservoir rock sample according to the following equation: S.sub.g=100-S.sub.w wherein S.sub.w is the water saturation in %; S.sub.w is the sum of the free water saturation, the water saturation and the corner water saturation; S.sub.g is the gas saturation in %. The method for determining the gas saturation of a tight reservoir uses model calculations, which avoids errors in the determination results of the gas saturation caused by water volatilization, surface adsorption, and observation of water flow during experiments.