Characteristics of Tight Dolostone Reservoir and Its Main Controlling Factors in the Submember Ma5₅ of Majiagou Formation in the Western Ordos Basin

Figure 8

Schematic diagram of formation mechanism of dissolution pore-type dolostone reservoir (Anh = anhydrite; Sa = halite; Md = dolomicrite; Mp = moldic pore; Dm = dissolution microfracture; Srd = surrounding debris; Cc = calcite cement; Br = breccia structure; Dpb = dissolved pore between breccias). ((a) Powdery crystal dolostone containing gypsum and halite; (b) gypsum and halite moldic pores; (c) geopetal structure; (d) dissolution pores between breccias).