Characteristics of Middle-Lower Ordovician Ultradeeply Buried Carbonate Reservoirs in Shunbei Area, Tarim Basin—A Case Study from Well SHBP1

Figure 2

The lower unit characteristics of Well SHBP1. Microscopic/petrographic characteristics of samples in the lower core: (a) Light gray siliceous rock. Silicification develops along fractures, layered siliceous bands, and pyrite, 8455.71-8455.73 m; (b) Light gray siliceous rock. Silica is mainly cryptocrystalline, quartz crystal growth, and residual filling along the fracture wall can be seen on the fracture surface, 8455.73-8455.77 m; (c) Qtz is present as the subhedral quartz crystal, which developed a few pores. Quartz fills the fractures, chalcedony is filled in the fractured-cavity, as observed in microscopic photo of XPL, 8455.74 m; (d) Silicified rock with crystalloblastic texture is composed of microcrystalline quartz and granular quartz, with large intercrystallite pores and reprecipitated calcite cement, 8455.73 m, XPL; (e) Siliceous rocks. It is dominated by microcrystalline quartzite, which consists of microcrystalline quartz and granular quartz with crystalloblastic texture, 8455.72 m, PPL; (f) Siliceous rocks. Partially magnified slice of E, microcrystalline quartz, 8455.72 m, XPL.

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