Measurements of Residual Gas Saturation by Unidirectional Spontaneous Imbibitions

Abstract

Residual gas saturation of core samples from T gas reservoir was determined by unidirectional spontaneous imbibitions experiments and the fitting formula for residual gas saturation calculation using initial gas saturation has been established. The residual gas saturation lies between 3.8% and 55%, which increases slightly with the increase of porosity and permeability. The experimental results are coincident with the calculations from Land's (1968) empirical formula; moreover, it agrees with the results from Agarwal's (1967) empirical formula at relatively low residual gas saturation, but as the residual gas saturation increases, the results given by Agarwal's model tend to be overestimated.

Keywords:

• water-drive gas reservoir
• residual gas
• residual gas saturation
• unidirectional spontaneous imbibition
• gas flooding

NOMENCLATURE

Swi	=	= original water saturation
Sgi	=	= initial gas saturation
Sgr	=	= residual gas saturation
Sgrm	=	= maximum residual gas saturation