关键词: 超深层, 立体成藏, 陆相致密气, 陆相页岩油, 勘探新领域, 资源潜力

Abstract: The natural gas resources in Sichuan Basin rank first in China, with the proven rate of only 18.8 % , indicating enormous potentials for exploration and development. In recent years, significant breakthroughs have been made in oil and gas exploration in new fields, new strata, and new types of marine carbonate rocks, unconventional marine gas, continental tight gas, and continental shale oil in deep to ultra-deep layers of Sichuan Basin, demonstrating tremendous resource prospects. Despite of the low degree of exploration, the marine carbonate gas reservoirs in deep to ultra-deep layers in the western and central Sichuan Basin display a 3D accumulation pattern in multiple series of strata with hydrocarbons supplied from excellent source rocks, vertically stacked and horizontally connected high-energy mound-beach reservoirs in many series of strata, good source reservoir configuration and developed fault conduit systems, which are expected to form a new trillion cubic meter scale reserve zone. The foreland subbasin-slope is a favorable area for the enrichment of continental tight gas in central-western Sichuan Basin, and two sets of petroleum accumulation systems are formed, i.e., Xujiahe Formation and the Jurassic Shaximiao Formation, in which Xujiahe Formation is the major source rock. A giant gas field of 100 billion cubic meters has been discovered with the cumulative produced geological reserves exceeding 10¹²m³, and has become a new growth pole for natural gas production in Sichuan Basin. Unconventional hydrocarbon-bearing strata series such as Permian and Jurassic shale, mudstone, and coal are continuously and stably distributed. Oil and gas are widely enriched and accumulated, and most abundant in central and eastern Sichuan Basin, and moreover exploration breakthroughs have been achieved. In the favorable exploration area for unconventional natural gas, the resources in the Permian reservoirs amount to nearly 8×10¹²m³; in the favorable exploration area for Jurassic shale oil, the resources are estimated to be 16.96 ×10¹²m³. The marine carbonate gas and continental tight gas in deep to ultra-deep layers in the western and central Sichuan Basin have been the main area for increasing reserves on a large scale in Sichuan Basin. Unconventional natural gas and continental shale oil are important resource replacement areas.

Key words: ultra-deep layers, 3D accumulation pattern, continental tight gas, continental shale oil, new fields of exploration, resource potential