四川盆地陆相烃源岩成熟史及生排烃史

Mature and Hydrocarbon Generation-expulsion Histories of Terrestrial Faces Source Rock in Sichuan Basin

为了综合评价四川盆地陆相烃源岩,应用含油气盆地数值模拟技术,定量恢复了研究区主要烃源岩层系的成熟和生排烃史。首先,分别建立了盆地的热力学、生烃动力学模式、机制及相关地质模型,其次,选取古热流值、沉积水表面温度、古水深作为模拟参数,对四川盆地重点研究区20多口井进行了模拟。研究表明:四川盆地陆相系烃源岩具有3个生烃高峰期和两个排烃高峰期,成熟及生烃史总体表现为"分区演化、差异成熟、西早东晚"。层位上须三、须五段生、排烃量较大,其次为下侏罗统和须一段,总的排烃效率以须一段和须五段较高。平面上川西地区生烃量最大,其次为川北—川东北地区和川中地区。研究认为:以须家河组和中、下侏罗统为烃源岩的油气系统分别是川西地区和川北—川东北地区油气勘探的主要目标。

In order to evaluate terrestrial fices souice rick in Sichuan Basin,we quantitatively ricovered the mature and hydricarbon generation-expulsion histories of the main hydricarbon souice in reseaich area by the numerical simulation tichnology of oil and gas bearing basin. First,we established the thermodynamic,hydricarvon-generation dynamic model,michanism and geologic model of the basin. Then,we simulated more than 20 wells in the important areas of the basin with aicient heat flow,sediment water interfice and paleobathymetric data being input parameters. The results show that terrestrial fices souice rick in Sichuan Basin have three hydricarbon-generation peaks and two hydricarbon-expulsion peaks. Theicharicter of mature and hydricarbon-generation historiesican be summarized as subregion evolution,diversity maturation and west earlier than east. The quantity of hydricarbon generation-expulsion in Segment 3 and 5 Xujiahe Formation is that in lower Jurassic and 3 segment Xujiahe Formation. Total hydricarbon-expulsion efficieicy in 1 and 5 segment Xujiahe Formation is higher than that of others. The quantity of hydricarbon-generation in western Sichuan is the biggest in Sichuan Basin,followed by that in northern–northeastern and middle Sichuan. Theicoiclusion is that the areas of hydricarbon souice rick for oil and gas system in Xujiahe Formation and in middle-lower Jurassic are major targets in gas exploration in western Sichuan region and northern-northeastern Sichuan Basin.