An Experimental Investigation of Permeability Reduction by Water Vaporization Process Associated with Gas Storage Process

Water vaporization and its impact on the formation productivity and injectivity are important issues dealt with during gas injection into porous media. It is clear that there are many other issues associated with underground gas storage projects but water vaporization and its induced permeability impairment are particularly important issues during gas injection in the candidate reservoir in this work. This paper investigates water vaporization in a candidate reservoir for underground gas storage. It is important to encounter two parameters in this process، which are water saturation reduction and permeability reduction in reservoir rock sample to form salt precipitation. Water saturation reduction causes permeability improvement، but scale formation reduces permeability. According to the results، the medium with higher permeability experiences an improved injectivity during gas injection، while the medium with lower permeability experiences an impaired injectivity. It is worth mentioning that both media suffer from permeability impairment. Finally، injectivity and productivity changes caused by water vaporization differ from case to case depending on the porous medium characteristics and the properties of fluid within the porous medium. Therefore، independent experiments should be conducted for different systems، since there is no accurate formulation to predict the mentioned permeability impairments. Also، special experiments are necessary for different media which are related to pore structure.