13:45 〜 15:15
[HRE11-P11] Identification of fluid types and their implications for petroleum exploration in the shale oil reservoir
キーワード：Fengcheng Formation, shale oil reservoir, fluid type, NMR T1-T2 map, lithology
The Fengcheng Formation in the Junggar Basin is a typical shale oil reservoir. This fine-grained sedimentary rock is more heterogeneous than sandstone due to lake-level fluctuations and seasonal changes. In shale oil and gas exploration and development, fluid type identification and evaluation of their controlling factors are significant challenges. By using thin sections, scanning electron microscopy (SEM), nuclear magnetic resonance (NMR) and X-ray diffraction (XRD), the characteristics of petrology, mineralogy and pore structure are analyzed. A total of six fluid types can be identified in the Fengcheng Formation, including free oil, adsorbed oil, kerogen, hydroxyls, adsorbed water and free water. Combined with the organic geochemical experiments and two-dimensional (2D) NMR, their boundary values on the T1-T2 map can be determined. In this study, different fluid types eliminated kerogen and hydroxyls can be combined into four fluid combination types, which are Type 1, 2, 3 and 4. They occur in the dolomitic shale (Type 1), mixed shale (Type 2), felsic shale (Type 3) and sandstone (Type 4) that act as reservoirs, respectively. Furthermore, the geometric means of T2 (T2gm) and T2 curves are effective parameters describing average pore size to distinguish different lithologies. As the average pore size increases, free water emerges in the mixed shale, and adsorbed water disappears in the felsic shale. After the lithology transforms into coarser sandstone, only movable fluids exist. Finally, the oil test results indicate that the main controlling factor of oil production in the Fengcheng Formation is fluid combination types rather than physical properties. This provides a theoretical basis for the subsequent shale oil exploration in the Fengcheng Formation.