“十二五”中国天然气地质理论研究新进展

New research progress of natural gas geological theories in China during the 12^(th) Five-Year Plan period

随着天然气勘探工作的不断深入,资源劣质化程度不断加剧、勘探对象也越来越复杂,需要不断发展和完善天然气地质理论,以指导寻找和发现更多的天然气资源。为此,"十二五"期间开展了大气田成藏地质理论的攻关研究,主要进展包括:①建立了不同地质条件下原油裂解生气和高演化煤系烃源岩生气模式;②建立了不同丰度、不同类型烃源岩排烃、滞留烃定量评价模型;③建立了天然气多参数、多指标成因鉴别图版;④建立了2种碳酸盐岩和2种致密砂岩沉积新模式;⑤建立了直接盖层盖储排替压力差评价新方法;⑥建立了大气田成藏模式,总结了大气田的形成主控因素与分布规律。进而深化了下述5大领域的天然气勘探理论,应用成效显著:①创新了古老碳酸盐岩大气田成藏地质理论认识,推动了四川盆地安岳特大型气田的发现和探明;②发展了大型致密砂岩气田成藏地质理论,指导了鄂尔多斯、松辽等盆地致密砂岩气勘探;③深化了台缘礁滩成藏理论,拓展了四川盆地台缘礁滩天然气的勘探;④深化了大型凝析气藏成藏机理与富集理论,指导了塔里木盆地大型凝析气藏的勘探;⑤完善了以生烃断槽为基本单元的火山岩气藏勘探理论,实现了火山岩气藏勘探的战略接替。

With the continuous deepening of natural gas exploration, the quality of discovered resources gets worse and exploration targets are getting more and more complicated, so it is necessary to develop and improve natural gas geological theories continuously in order to tap and discover more natural gas resources. Therefore, geological theories on the formation of large gas fields were studied during the 12th Five-Year Plan period and the following progresses were mainly achieved. （1） Gas generation modes were established of oil cracking and highly evolved coal-measure source rocks in different geologic conditions. （2） A model was set up for evaluating quantitatively the hydrocarbon expulsion and detainment of various source rocks with different abundance. （3） Natural gas genesis identification chart was built up with multiple parameters and indexes. （4） Two carbonate rock sedimentation patterns and two tight sandstone sedimentation patterns were established. （5） A new method was developed for evaluating caprock-reservoir displacement pressure difference of immediate caprocks. （6） The hydrocarbon accumulation pattern of large gas fields was established and their main controlling factors and distribution laws were summarized. Then, the natural gas exploration theories were deepened in the following five fields and their application achievements are remarkable. First, the hydrocarbon-accumulation geological the- ory used for large ancient carbonate gas fields was innovatively understood to promote the discovery and confirmation of the Anyue supergiant gas field in the Sichuan Basin. Second, the hydrocarbon-accumulation geological theory suitable for large tight sandstone gas fields was developed to guide the exploration of tight sandstone gas in the Ordos and Songliao Basins. Third, the hydrocarbon-accumulation theory of platform margin reefs was deepened to expand the exploration of platform margin reef gas in the Sichuan Basin. Fourth, the hydrocarbon accumulation mechanism and enrichment theory of large condensate gas reservoirs were deepened to guide the exploration of large condensate gas reservoirs in the Tarim Basin. And fifth, the exploration theory of volcanic gas reservoirs with hydrocarbon-generation fault troughs as basic units was completed to realize the strategic replacement of volcanic gas reservoir exploration.