Abstract:Volcanic rocks constitute the main deep exploration target in eastern Changling depression. Drastic changes in volcanic lithofacies and lithology as well as strong reservoir heterogeneity make it difficult to predict favorable reservoir belts. Based on volcanic exploration results in the depression, the authors studied the volcanic features, distribution, main controlling factors for the formation of reservoirs and the exploration potential. The volcanic rocks in the depression are mainly distributed along big deep faults and superimposed by many times of volcanic eruption in the vertical direction. There exist four kinds of volcanic lithofacies and nine sorts of subfacies. Explosive tuff and overflow rhyorite reservoirs have many gas pores, solution pores and fractures, and possess the best physical properties. The deep formation in the depression has experienced a low exploration degree but possesses abundant hydrocarbon resources, and volcanic rocks are distributed extensively there and have good reservoir-forming conditions, suggesting a very promising hydrocarbon exploration potential.