关键词: 三塘湖盆地, 非常规油气, 凝灰岩, 地质理论, 关键技术, 实践经验

Abstract: A breakthrough has been made on the tuff reservoir, a new type of tight oil reservoir, in the Permian Tiaohu Formation in Santanghu Basin. In order to clarify the reservoir forming mechanism and enrichment law, the vertical and horizontal distribution of sweet spots, efficient technology for reserve producing, the distribution law of source rocks, microscopic characteristics of reservoirs, brittleness of reservoir rocks, and oil-bearing ability were investigated. The theory and understanding of exploration and development of the tight tuff reservoir in the Santanghu Basin were summarized using drilling, logging, production tests, and analytical test data based on tight oil geological theory, exploration technology, and development technology, etc. The results show that the oil reservoir enrichment is jointly controlled by the effective configuration of source rocks, stable basin structures, shallow lake environment, tuff composition, later devitrification and dissolution, good match of devitrification and oil filling timing. “Self-source wetting, mixed-source filling, fault-fracture transport, and sweet spot enrichment” characterize the tuff oil reservoir. By developing horizontal well volume fracturing technology and scale development experiments, the tight oil in the Santanghu Basin is produced efficiently. The exploration potential of the tight oil in the Santanghu Basin is huge, and the geological resources of tight oil in the Tiaohu Formation are up to 143 million tons. It is an important resource that guarantees a sustainable and stable oil production. To benefit from the development of the tight oil in the Tiaohu Formation, it is necessary to further identify sweet spots, develop technological innovation, improve organization and management, reduce costs, and increase benefits. These are important factors for the sustainable and stable production of the Tuha Oilfield.