Pore Fluid Evolution Influenced by Volcanic Activities and Related Diagenetic Processes in a Rift Basin: Evidence from the Paleogene Medium-Deep Reservoirs of Huanghekou Sag, Bohai Bay Basin, China

Figure 6

Photomicrographs of quartz grains dissolution and K-feldspar albitization in the Paleogene sandstone reservoirs in the well BZ-1 of Huanghekou Sag. (a) Environmental scanning electron microscope (ESEM) image of dissolved quartz (Q), E₂s₁, 3037 m (9964 ft). (b) Dissolution of quartz showing embayed shape (marked with black dot line), E₂s₁, 3037 m (9964 ft). (c) Backscattered electron (BSE) image of quartz dissolution along grain boundary and fracture, E₃d₃, 2944 m (9659 ft). (d) Albitization (Ab) of K-feldspar along cleavage plane, E₃d₃, 2944 m, BSE image (9659 ft). (e) SEM photograph of albite crystals in partly dissolved K-feldspar grain, E₂s₁, 3037 m (9964 ft). (f) K-feldspar was replaced by albite, E₂s₁, 3037 m (9964 ft). Ab = albitization, Kf = K-feldspar, Kln = kaolinite, and Q = quartz.

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