Laminae combination and shale oil enrichment patterns of Chang 73 sub-member organic-rich shales in the Triassic Yanchang Formation, Ordos Basin, NW China

XI Kelai,LI Ke,CAO Yingchang,LIN Miruo,NIU Xiaobing,ZHU Rukai,WEI Xinzhuo,YOU Yuan,LIANG Xiaowei,FENG Shengbin

Fig. 7. Occurrence characteristics of crude oil in “organic-rich + silt-grade feldspar-quartz” lamina combination shale strata of the Yanchang Formation Chang 73 sub-member in the Ordos Basin. (a) and (b) Well Cai 10, 1967.30 m, Raman spectrum features of crude oil in feldspar dissolved pore of silt-grade feldspar-quartz lamina and of crude oil in organic-rich lamina; (c) Well Cai 30, 1964.88 m, feldspar dissolution and oil occurrence characteristics in silt-grade feldspar-quartz lamina; (d) Well Cai 30, 1962.95 m, crude oil trapped in feldspar dissolved pore and microfracture in organic-rich lamina and silt-grade feldspar-quartz lamina; (e) comparison of reflection microscopic infrared spectra in positions marked in Fig. 7d; (f) comparison of transmissivity microscopic infrared spectra in positions marked in Fig. 7d.