Diagenetic Fluid and Its Impact on Sandstone Reservoirs in the Southern Boxing Sag, Dongying Depression, Bohai Bay Basin, China

Figure 4

Photomicrographs of carbonate cements, dissolved feldspars and secondary minerals in thin sections. (a) F1, 3321.5 m: the dissolution of calcite and feldspar with the precipitation of secondary quartz; (b) F25, 2998.5 m: the leached feldspar and associated secondary minerals; (c) G351, 2444.5 m: feldspar dissolution and Fe-calcite and ankerite precipitation; (d) G351, 2447 m: the leached feldspar and associated secondary minerals, and the secondary intragranular pore is destroyed by ankerite precipitation; (e) F1, 3314.6 m: the precipitation of secondary quartz mineral with a width of approximate 40 μm; (f) F104, 3038.9 m: the leached feldspar and associated quartz overgrowths; (g) G891, 2808.4 m: early calcite cement and late ankerite cement; (h) G351, 2444.5 m: the dissolution of calcite and feldspar accompanied by clay minerals, and ankerite cement; (i) F1, 3319.1 m: the intergranular pores are destroyed by ankerite cements. Note: Qo: quartz overgrowth, R: rock fragment, Fd: feldspar dissolution, Cc: calcite, Fc: ferrocalcite, and An: ankerite.

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