Effects of Microheterogeneous Wettability and Pore-Throat Structure on Asphaltene Precipitation in Tight Sandstone: Results from Nuclear Magnetic Resonance

作者：Zhenzhen Zhou, Yiqian Qu, Xin Cheng, Yu‐Ting Cheng, Shuqi Lan, Zhengqi Yang, Liancheng Wei, Wei Sun, Hanning Wu · 发表于：ACS Omega · 年份：2024 · DOI：10.1021/acsomega.4c07672 · 被引用次数：8 · 研究领域：Petroleum Processing and Analysis、Hydrocarbon exploration and reservoir analysis、Enhanced Oil Recovery Techniques

High Resolution Image Download MS PowerPoint Slide The pore throat structure and microheterogeneous wettability of tight sandstone reservoirs are complex, which leads to varying asphaltene precipitation locations, contents, and distributions in different pores during CO 2 flooding. Clarifying the heterogeneous wettability of different pore throat structures and their effects on asphaltene precipitation and adsorption is crucial for improving CO 2 displacement efficiency. A series of experiments were conducted in this study, including X-ray diffraction (XRD), cast thin section (CTS), field emission scanning electron microscopy (FE-SEM), high-pressure mercury intrusion (HPMI), environmental scanning electron microscopy (E-SEM), nuclear magnetic resonance (NMR), and CO 2 flooding experiments, to investigate the pore structure complexity of tight sandstone reservoirs of the Yanchang Formation in the Ordos Basin, China. Furthermore, we investigated the variations in microheterogeneous wettability across diverse pore-throat structures and elucidated the impact of heterogeneous wettability on asphaltene precipitation during CO 2 flooding. The findings indicate that the type and configuration of pore throats are crucial factors influencing microheterogeneous wettability. The intergranular pores are dominated by mixed wetting, and most of the dissolution pores exhibit oil wetting. The surface of Illite shows drop-like water under E-SEM, which is mainly oil wetting, whereas the surface...