Impacts of the Pore–Throat Structure on Fluid Mobility in Tight Sandstone: Insight from an Improved Method Based on Rate-Controlled Porosimetry and Nuclear Magnetic Resonance

作者：Siqi Ouyang, Xiuxiang Lü, Yuanyuan Zhang, Lei Chen, Yiqian Qu, Wei Sun · 发表于：Energy & Fuels · 年份：2022 · DOI：10.1021/acs.energyfuels.2c03285 · 被引用次数：9 · 研究领域：Hydrocarbon exploration and reservoir analysis、NMR spectroscopy and applications、Hydraulic Fracturing and Reservoir Analysis

The microstructure of pores strongly influences fluid mobility in tight sandstone reservoirs. The impacts of the pore–throat structure on fluid mobility are restricted due to the limitations of existing methods for determining pore–throat structures. Therefore, the methods utilized to obtain more comprehensive and accurate pore–throat information need to be further discussed by combining multiple experiments. In this research, eight samples were selected from the Upper Triassic Yanchang Formation in the Ordos Basin to investigate the microstructure and its impacts on fluid mobility by means of nuclear magnetic resonance (NMR), rate-controlled porosimetry (RCP), scanning electron microscopy, and thin sections. The throat radii in the throat, pore–throat, and pore areas were studied by combining NMR and RCP with an improved method. The throat radius and pore–throat volume affect the movable fluid from connectivity and movable ratio, respectively. The throat and pore–throat (pore) areas belong to unrelated movable fluid networks. Each area contains intragranular and intergranular spaces. Irregularly shaped pores commonly occur in the intragranular space, with strong connectivity. The pores with regular shape in the intergranular space connect a small amount of throat, and a large number of clay minerals divide the space into small throats. Clay minerals reduce fluid mobility by increasing the thickness of the water film in the throat. Therefore, fluid mobility in the intragranul...