Pore Structure and Fractal Characteristics of Tight Sandstone: A Case Study for Huagang Formation in the Xihu Sag, East China Sea Basin, China

Various experiments, including routine petrophysical measurements, thin section and scanning electronic microscope (SEM), high-pressure mercury intrusion (HPMI), nuclear magnetic resonance (NMR), were performed to characterize the microscopic pore structure of tight sandstone in Huagang Formation (E3h), Xihu Sag, East China Sea Basin, China. Specifically, NMR was used investigate dynamic variation fractal dimensions during centrifugation, comparison HPMI clarify difference dimensions. The results showed that there four types pores observed SEM images: primary intergranular pores, dissolution intragranular micropores within clay aggregates. geometric shape size different huge differences, indicating formation complex diverse structures E3h formation. flow capability reservoir dominated by large while storage capacity determined small pores. calculated data water residing with low removed preferentially, resided always more complicated than water, which indicated affected complexity structure. Based on dimension from NMR, it found trends consistent, as radius throat increased, became complicated. Both macropores (Dmac) movable-fluid (Dmov) can reflect effectively, but correlations between HMPI poor, could be due working mechanism these methods.