A novel method for determining water saturation of porous media in relative permeability measurement using DPT

Abstract

Abstract Relative permeability is essential for understanding porous media’s gas and water seepage characteristics and establishing production schedules in practical engineering applications. However, the movable water is too small to be detected in ultra-lowpermeability rocks, and it is difficult to determine the water saturation in the relative permeability measurement accurately. In this study, a differential pressure transducer (DPT) was applied to self-developed apparatus to quantify displaced water precisely. The results indicate that: (a) both the permeability and the relative permeability measurement results show high stability in repeatability tests with the application of DPT. (b) The final cumulative water flow data measured by the DPT is reliable; the relative error of the electronic balance and DPT value was less than 4%. (c) This self-developed instrument can obtain the relative permeability curve for ultra-low permeability rocks, such as tight sandstone and anthracite coal. Although there are limitations, this technique provides an economical and reliable pathway for studying the seepage characteristics of gas and water in ultra-low permeability rocks.