Influences of diagenetic effects on volcanic rock reservoirs under two different sedimentary environments

According to the studies of rock types and reservoir space features of Carboniferous volcanic rocks in the Santanghu Basin,there were two kinds of environments for volcanic rock generation including subaerial and subaqueous in the study area.Based on core description,casting chip,scanning electron microscopy and element analysis,the generation features of volcanic rocks under the two different environments and the corresponding influences on reservoirs were discussed from the aspects of diagenetic effects.It was concluded that different diagenetic effects influenced volcanic reservoirs in different extents.The volcanic rocks which erupted and deposited on land in the study area were severely filled by zeolites and chlorites,and then improved obviously due to weathering and leaching.The extent of weathering and leaching was closely related to the improvement of reservoir.The volcanic reservoirs which deposited under water were improved owing to organic acid erosion.Primary pores were seldom found and a large amount of matrix dissolved holes generated.The generation mechanisms of subaqueous volcanic reservoirs pointed out new areas for explorations in the future.