The relationship between physical property evolution and reservoir formation in volcanic rock reservoirs: The Huoshiling Formation, Dehui Fault Depression, southern Songliao Basin

Abstract

The Huoshiling Formation in the Dehui Fault Depression has emerged as a significant target for tight oil and gas exploration in volcanic rock reservoirs. This research investigates the tight gas reservoirs of the Huoshiling Formation through a combination of core observation, thin-section analysis, image recognition, and thermal simulation experiments. The study explores diagenetic processes, the factors influencing reservoir physical properties, and the development of a coupling of reservoir physical property evolution and oil and gas accumulation. Three primary types of diagenesis in the Huoshiling Formation have been identified. Detailed diagenetic evolution sequences are established through thin-section observation and analyses of authigenic minerals, pore types, and diagenetic mineral contact relationships, complemented by carbon and oxygen isotope analysis. An innovative technique integrating cast thin-section scanning and large-field stitching, and image recognition is developed to quantitatively assess the impact of various diagenetic processes on reservoir properties. Reconstructing burial, thermal, and hydrocarbon generation histories and integrating fluid inclusion homogenization temperatures, reveals the peak periods of gas and oil generation. A porosity evolution history map was constructed using the diagenetic evolution sequence, computational image analysis, and back-stripping inversion methods. This analysis elucidates the relationship between the evolution of reservoir physical properties and hydrocarbon accumulation timing in the Huoshiling Formation.