关键词: 火山岩储层, 主控因素, 流体, 孔隙演化, 中生界, 莱州湾凹陷, 渤海湾盆地

Abstract: Based on core and cast thin section data, the reservoir characteristics, reservoir controlling factors,  and reservoir evolution of Mesozoic volcanic rocks in block Kenli-16 were studied by means of microscopic identification, scanning electron microscopy, porosity and permeability testing, constant velocity mercury injection, image analysis and burial history analysis. Seven  types of 16 reservoir spaces are identified in block Kenli-16. The reservoir type is pore-fracture type. It is characterized by large pore size and medium-big throat, and belongs to high-quality volcanic rock reservoir. The reservoir is controlled by lithology, dissolution diagenesis, and tectonism and has no obvious relationship with burial depth. The descending order of reservoir quality is tuff, lapilli, volcanic breccia, welded breccia, reworked volcaniclastics, ignimbrite, andesite, and dacite. The fluid contributes greatly to the porosity formed by the dissolution of feldspar porphyry and matrix, the results show that pre-burial weathering and burial fluid dissolution are important stages of reservoir formation. The amygdaloid, intergranular pores, explosive cracks, macroscopic and microscopic cooling fractures, and crypto-explosive fractures were generated during syn-eruption stage, and their contribution rate to pores was limited. The tectonic fractures of pyroclastic lava and lava are mainly formed in the pre-burial stage, the left-lateral strike-slip stress field of Tanlu fault zone in Cretaceous period and the extensional environment of Shahejie stage. The tectonic fractures of pyroclastic rocks are mainly formed in the post-burial stage, the right-lateral strike-slip stress field of Tanlu fault zone in Cretaceous period and the extensional environment of Shahejie stage. In conclusion, pyroclastic rocks that are subjected to strong structural transformation and weathering in shallow buried areas are favorable targets for exploration.

Key words: volcanic reservoirs, main controlling factors, fluid, pore evolution, Mesozoic, Laizhou Bay depression, Bohai Bay basin