四川盆地油气勘探新领域、新类型及资源潜力

New fields,new types and resource potentials of hydrocarbon exploration in Sichuan Basin

四川盆地天然气资源量居中国首位,目前探明率仅为18.8%,勘探开发潜力巨大。近几年,四川盆地油气勘探相继在深层—超深层海相碳酸盐岩、海相非常规天然气、陆相致密气及陆相页岩油等新领域、新层系、新类型取得重大突破,展示出巨大的资源前景。川西—川中地区深层—超深层海相碳酸盐岩气藏多层系立体成藏,优质烃源岩供烃,多层系高能丘滩相储层垂向叠置、横向连片,源-储配置好,断裂输导体系发育,但勘探程度低,有望形成新的万亿立方米级规模增储区。川西—川中前陆坳陷—斜坡带为陆相致密气富集有利区,以须家河组为主力烃源岩,形成须家河组、侏罗系沙溪庙组两套成藏体系,已发现千亿立方米级大气田,累计提交地质储量超过1×10^(12)m^(3),成为四川盆地天然气产量新的增长极。二叠系和侏罗系页岩、泥灰岩、煤岩等非常规含油气层系均连续稳定分布,油气大面积富集成藏,以川中—川东地区最为富集,已取得勘探突破。二叠系非常规天然气有利勘探区资源规模近8×10^(12)m^(3),侏罗系页岩油有利勘探区资源量为16.96×10^(8)t。川西—川中地区深层—超深层海相碳酸盐岩天然气以及陆相致密气已形成四川盆地新的规模增储主阵地,非常规天然气及陆相页岩油是重要的资源接替领域。

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 1012m^(3),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 8×10^(12)m^(3);in the favorable exploration area for Jurassic shale oil,the resources are estimated to be 16.96×10^(12)m^(3).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.