Reservoir Sensitivity Analysis of Tight Sandstone and Its Controlling Factors: A Case Study from Chang 4+5 to Chang 6 Reservoirs in N 212 Well Block of Nanniwan Oilfield, Ordos Basin

Figure 7

Pore characteristics of the Chang 4+5 and Chang 6 reservoirs in the N 212 well block in Nanniwan Oilfield. ip = intergranular pore; dp = dissolved pore; Q = quartz; F = feldspar; R = rock fragment; mf = microfracture. (a) Intergranular pores, Chang 4+5, well N 212, 692.59 m, CTS; (b) intergranular pores, Chang 4+5, well N 212, 691.69 m, SEM; (c) intergranular pores and dissolved pores in feldspar, Chang 4+5, well N 212, 770.52 m, CTS; (d) dissolved pore in feldspar, Chang 4+5, well X33, 791.77 m, CTS; (e) dissolved pore in feldspar, Chang 4+5, well X820, 825.0 4 m, CTS; (f) dissolved pores and quartz filling in the intergranular pore, Chang 6, well X33, 767.30 m, SEM; (g) dissolved pores in debris, Chang 6, well N 212, 765.00 m, CTS; (h) dissolved pores in debris, Chang 6, well X33, 768.00 m, CTS; (i) microfractures, Chang 6, well X820, 760.99 m, CTS.