Abstract:Objectives: There are two kind of conduit facies including the volcanic conduit and the hydrothermal channel develop in the volcanic rock development zone. Much attention has been focused on the volcanic conduit, while very few work on the hydrothermal channel have been done, especially the significance of petroleum geology of it. We study the characteristics and hydrocarbon significance of two channels.Methods: Combining the threedimensional seismic data, drilling data, profiles and glass slides, we make multiscale comprehensive analysis on the volcanic conduit and the hydrothermal channel. There are some differences in lithofacies and seismic facies of them.Results:The volcanic conduit and the hydrothermal channel are shown as the inverted cones whose upper end is much thicker than the lower end. The volcanic conduit whose reflection amplitude is different from the host rock is mostly magmatic filling, develops a typical stacking structure, has the obvious velocity anomaly, and often is associated with a larger scale of high amplitude effusive facies. The volcanic conduit is characterized by "two strong and one weak" seismic features, that is, strong reflection at the top and bottom, and weak reflection in the middle. The hydrothermal channel is filled with the surrounding rock debris and has no velocity anomaly. The reflection amplitude of the hydrothermal channel without the development of the associated effusive facies is not very different from the surrounding rock. Its seismic feature is "one strong and one weak" , which is characterized by strong reflection at the bottom and weak reflection in the upper part. The volcanic conduit is formed by magma intrusion. The hydrothermal channel formation is controlled by the fluidization and disaggregation of rock at depth as a consequence of intrusive igneous activity. The two types of channels have different control functions of hydrocarbon. The volcano conduit is beneficial to reservoir development and not to the development of cap rock, while the hydrothermal channel is beneficial to the cap rock development and not to reservoir development. Conclusions: Based on the different control functions of hydrocarbon, combining the distribution characteristics of the conduit facies, the favorable exploration zone in the research area is pointed out. This study has important guiding significance for oil and gas exploration in the volcanic development zone.