Determination of Formation Time of Calcareous Cements in Marine Sandstone and Their Influence on Hydrocarbon Accumulation: A Case Study of the Carboniferous Donghe Sandstone in the Hadexun Oilfield, Tarim Basin

Figure 3

Distribution of the pores and cements in calcareous sandstones of Hadexun Oilfield.

(a) Oil-bearing and oil-free sandstones, 5070.07 m, polarizing microscope with plane-polarized light, Well HD4

(b) Oil-bearing and oil-free sandstones, 5070.07 m, polarizing microscope with cross-polarized light, Well HD4

(c) Oil-bearing and oil-free sandstones, 5070.07 m, polarizing microscope with plane-polarized light, Well HD4

(d) Oil-bearing and oil-free sandstones, 5070.07 m, polarizing microscope with crossed + λ polarized light