In the Chaganhua Gas Field within the Songnan Fault Depression

the Huoshiling Formation's volcanic reservoirs exhibit an average porosity of 4.5% and a permeability of 0.08×10

-3

μm

indicating a dense and highly heterogeneous nature. Due to this complexity

a comprehensive approach

testing a broad set of reservoirs

is required to establish effective classification criteria. This study used physical property data

high-pressure mercury injection

nuclear magnetic resonance

and other experiments to analyze the microstructure of volcanic reservoirs. Through multi param

eter comparison

a microscopic classification standard was established. Nuclear magnetic logging served as a bridge between microscopic and macroscopic parameters

facilitating the creation of a comprehensive evaluation framework for classifying volcanic reservoirs. This framework encompasses microscopic structural features such as pore throat radius

displacement pressure

mercury saturation

alongside macroscopic parameters obtained from nuclear magnetic logging and other experiments

such as the T2 spectrum distribution

centrifugal saturation

porosity

permeability

saturation

acoustic time difference

lithology density

and resistivity. Reservoirs are categorized from high to low quality into classes A

B

and C based on this comprehensive set of criteria. This method has strong operability and provides a reliable basis for the testing plan of new drilling and the optimization of sweet spots in exploration and development of horizontal wells. The research methods and understanding have certain reference significance for the classification research of volcanic reservoirs.