Abstract: In view of existing problems of poor stable production and reduced areas covered by prospecting rights in Huanxiling Oilfield, it is increasingly important to seek for commercially economic reserves of oil and gas reservoirs and to enhance the support to sustainable stable production, and it is imperative to actively study the exploration of special lithological reservoirs. The genesis and reservoir characteristics of volcanic rock in Qijia Area were described in detail based on the data of drilling, logging, core and seismic interpretation, and the exploration potential of volcanic reservoir in Qijia Area was discussed from the aspects of hydrocarbon accumulation factors and completion well productivity patterns. It was found in the study that the lithology of the volcanic rocks in Qijia Area was complex, with three stages of texture, namely, andesite porphyritic texture, intermatrix intergranular hidden texture, basalt stomatal porphyritic texture, gabbro texture and tuff volcanic tuffaceous texture. The reservoir characteristics of the volcanic reservoir were dominated by weathered crust, and the reservoir space included both pore and fracture media; the exploration potential of the volcanic reservoir was concentrated in the northern section near the western fault; the reservoir enrichment was controlled by lithology, tectonic morphology, weathered crust development and other factors. The study concluded that the volcanic reservoir in Qijia Area had a good productivity which was strongly correlated with lithology, tectonics and reservoir space development. The study results can be used as a reference for the in-depth exploration of the volcanic rocks in Qijia Area and as guidance for the exploration and development of volcanic rocks in other similar areas.

Key words: volcanic rock, lithological characteristics, reservoir geological characteristics, logging response characteristics, exploration potential, Qijia Area