Characteristics of Carboniferous Volcanic Reservoirs in Beisantai Oilfield, Junggar Basin
Table 2
Rock types in the Xiquan block.
Rock category
Main rock name
Mineral composition
Remark
Pyroclastic rocks
Volcanic breccia
The main components of the rock are igneous metamorphic rock blocks with a diameter of 3 mm–10 mm, the lava fragments are mostly tuff, and the glass fragments and whole stones are less.
Reservoir rock
Breccia tuff
The igneous metamorphic rock blocks with the main composition of 3 mm–5 mm contain lava fragments mostly tuff and fewer glass fragments and whole stones.
Reservoir rock
Tuff
The main components of the rock are volcanic debris and terrigenous debris. The volcanic debris is mainly composed of volcanic ash, wave debris, crystal debris, and a small amount of rock debris, and the particle diameter is less than 2 mm.
Nonreservoir rock
Volcanic lava
Andesite
The rock composition is equivalent to diorite, and the phenocrysts are mainly plagioclase and dark minerals (common dark minerals are pyroxene, amphibole, and biotite). The matrix is mainly composed of plagioclase crystallites, pyroxene, chlorite, and andesite glass.
