Vesicles and Reservoirs of Basic Lava Flows in the Laoheishan and Huoshaoshan Volcanoes, NE China

As an important part of the lava flow reservoir, vesicles affect reservoir performance to some extent. To explore the distribution, origins and importance of vesicles in different facies belts of basic lava flows. In this study, we selected representative field outcrops and samples from different facies belts of the Laoheishan and Huoshaoshan lava flows in the Wudalianchi volcanics, Heilongjiang Province, identified and examined vesicles, measured their porosity and permeability, and analyzed their surface porosity. Three facies belts of vesicle shape, size, quantity, arrangement, origin, and connectivity between vesicles and fractures were identified. The results showed that the vesicles in the crater–near-crater belt were ellipsoidal and spherical, with many vesicles. The vesicles in the proximal belt were dominated by many ellipsoids with a uniform distribution. The vesicles in the distal belt were dominated by spherical and ellipsoidal vesicles, with a few tubular vesicles and a small number of vesicles. The findings suggest that the crater-near-crater belt and proximal belt have the best reservoir performance, whereas the distal belt has the worst.