Chemically Active Elements of Reservoir Quartz Cement Trace Hydrocarbon Migration in the Mahu Sag, Junggar Basin, NW China

Figure 2

Morphological characteristics of quartz under the microscope. (a) Quartz replaced by and infilled with clay, with oil stains (sample B63; 2452 m; T₁b; 5×; plane-polarized light). (b) Inclusion-rich and oil-stained quartz overgrowth (sample D15; 4245 m; T₁b, 5×; plane-polarized light). (c) Quartz dissolved and replaced by clay, with oil stains (sample AH2; 3313.56 m; T₁b; 5×; plane-polarized light). T₁b = the lower Triassic Baikouquan Formation.

(a)

(b)

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