Research Article

Characteristics of Carboniferous Volcanic Reservoirs in Beisantai Oilfield, Junggar Basin

Table 4

Pore types of volcanic rock reservoirs.

Pore typeCauseDistribution characteristicsFilling situation

Primary poresStomataGas expansion and contractionPartially covered by chlorite and turbiditePartially covered by chlorite and turbidite
Amygdala, inner holeRemaining pores in amygdala formed by mineral-filled stomata that are not filledCalcite fillCalcite fill
Intracrystalline pores, matrix poresDiagenetic compaction among pyroclastic particlesPartially filled with turbidite, followed by chlorite and calcitePartially filled with turbidite, followed by chlorite and calcite

Secondary poresDissolution poresPores formed by dissolution and dissolution under the action of hydrothermal fluidFilling, poor connectivity, little contribution to reservoir physical propertiesFilling, poor connectivity, little contribution to reservoir physical properties
Intergranular poresTiny pores formed by clay mineralization, recrystallization, and dissolutionUnfilled and oilyUnfilled and oily

CrackTectonic seamGround stressHalf-filledHalf-filled
Dissolution seamWeathering leaching erosionHalf-filled and communicating matrix poresHalf-filled and communicating matrix pores
Condensation shrinkage jointsCold shrink differential movementCalcite full to half fillingCalcite full to half filling