“源控论”再认识——以四川盆地天然气勘探为例

Further Understanding the Theory of Source Control

烃源作为成藏的首要条件,没有陆相、海相之分,没有地域之别,也没有油藏、气藏的不同。在海相过成熟碳酸盐岩干气区由油系烃源层、煤系烃源层形成的烃源,制约着气藏的形成与展布。其成藏模式除自源型外,更多的是异源型(多为自下而上生运聚成藏)或混源型,在纵向上跨度大且往往具多次成藏史。四川盆地大中型气田勘探经验证实,在天然气上升为主要勘探对象的地层,只有气源量大于散失量才可能成藏,所以,成藏不仅要有丰富的烃源潜量,而且要有高烃潜量值(QHGG),其值一般为下古生界>上古生界一中生界>中生界—新生界。

Hydrocarbon source as a first important pool-forming condition, there is no any difference between marine and continental facies,oil-pool and gas-pool as well as where it comes from. The gas-pool formation and distribution are controlled by hydrocarbon source from oil-measure and coal-measure strata which constitute a dry gas area of marine over-mature carbonate rock.The pool-forming patterns are common in other source or mixture source besides self source,with multitime pool-forming history.The exploration experience of Large- medium scales of gas fields in Sichuan Basin suggests that the strata where natural gas is a major exploration target may form a pool only when the quantity of gas source is more than the lost one.Therefore it is needed to have not only a plenty of hydrocarbon potential but also a high intensity of gas- generating.General speaking,it is the best in Lower Paleozoic,then Upper Paleozoic-Mesozoic,then the Cenozoic.