Acid-base alternation diagenesis and its influence on shale reservoirs in the Permian Lucaogou Formation, Jimusar Sag, Junggar Basin, NW China

WANG Jian,ZHOU Lu,LIU Jin,ZHANG Xinji,ZHANG Fan,ZHANG Baozhen

Fig. 4. Acid and alkali diageneses in Lucaogou Formation. (a) Well Ji 33, 3663.21 m, calcite cement, plane-polarized light; (b) Well Ji 30, 4052.46 m, dolomite cement, orthogonal light; (c) Well Ji 41, 3917.10 m, dolomite crystal, FESEM (Field emission scanning electron microscopy); (d) Well Ji 174, 3202.30 m, dark gray analcime, gray-white ankerite, and siderite indicated by bright spot, backscattered electron image; (e) Well Ji 10012, 3176.70 m, authigenic almonite crystals, FESEM; (f) Well Ji 10025, 3491.85 m, illite/smectite mixed-layer mineral in beehive shape, FESEM; (g) Well Ji 10025, 3482.46 m, schistose illite, FESEM; (h) Well Ji 174, 3202.00 m, irregular bay dissolution at quartz particle edges, reflected light; (i) Well Ji 10025, 3462.15 m, dissolution pores in feldspar grains, FESEM.