Experimental study on the pressure-depleted flow of natural gas in a cluster of combined tight cores with a certain water saturation

Abstract

A novel experiment on gas flow in a cluster of combined tight cores was designed to study the degree of reserve recovery of tight gas reservoirs. The composition of the experimental apparatuses and the function of each apparatus are described in detail. An important apparatus was a clamping device that was 50 cm in length. Five pressure gauges were distributed at five different positions on the clamping device to monitor the gas flow pressure. Ten basic operation steps and a formula to determine pressure depletion degree are provided. We conducted 7 experiments using 30 core specimens and real natural gas collected from a tight reservoir in the Ordos basin of China. We categorized the specimens into three groups and designed low, middle and high water saturations and gas flow rates to study the influences of the physical properties, water saturation and gas rate on the degree of reserve recovery. We plotted dynamic pressure curves and calculated the pressure depletion degree, which quantitatively reflected the degree of reserve recovery of the example reservoir. We comparatively analysed the pressure depletion characteristics among different measurement points and experimental conditions. The research results showed that our designed experiment was useful and valuable.