Oil and gas reservoir characteristics of volcanic rocks and hydrocarbon accumulation regularity in Minqiao area

Volcanic oil reservoir of MinQiao area in Jiangsu oilfield is a typical basalt reservoir with more extrusive periods.Through core observation and experimental analysis,the results indicate there are two kinds of volcanic lava and igneous sedimentary rock developed in the area.The igneous rock reservoir developed the two types of reservoir space,the primary and secondary ones,with the characteristics of medium-low porosity,low permeability,strong heterogeneity,etc.After research on single well and profiles analysis,the igneous rock developed multiple periods and each period can be divided into four types of lithofacies.Different lithofacies are of different porosity characteristics.Based on faults development and fracture distribution analysis,the normalfaults not only control the thickness of the igneous rocks but also control the development of structural fracture.The fractures communicate the the pores and solution pores,forming the effective reservoirs for the igneous rocks.Finally the hydrocarbon from the deep sag accumulated through the faults.Based on this understanding,the accumulation pattern of fault-fracture-pore has been provided.