琼东南盆地深水区古近系层序地层特征及烃源岩分布预测

Paleogene sequence stratigraphy and source rock distribution in the deep water area,Qiongdongnan basin

在充分利用琼东南盆地北部浅水区钻井资料以及二维地震资料的基础上,运用层序地层学和沉积学等理论方法,以陵水凹陷为主要研究区建立了古近系地堑式和半地堑式的层序格架样式,总结出了单阶断裂坡折型、多级断阶坡折型和挠曲坡折型等3种主要层序构成样式,理清了陵水凹陷古近系崖城组高丰度海陆过渡相含煤系烃源岩发育受相对海平面变化、构造及古地形、沉积与沉降速率等因素的控制,并确立了烃源岩的发育模式。在此基础上,采用分频谱成像技术对研究区内发育的含煤系地层进行了识别,认为陵南低凸起与陵水凹陷东南缘相接的缓坡带、松南低凸起与松南凹陷西南缘相接的缓坡带和松南低凸起南侧构造脊的西倾没端等处为高丰度海陆过渡相烃源岩发育区带。

On a basis of the drilling and 2D seismicdata in the northern shallow-water area,Qiong-dongnan basin,and by applying the theories of se-quence stratigraphy and sedimentology,the se-quence framework styles of graben and half-grabenwere established,and three major sequence typeswere also identified,including single-terrace-faul-ted slope break,multi-terrace-faulted slope break and flexural slope break,in the main research are-a,i.e.Lingshui depression.For the rich coal-measure source rock of oceanic-continental transi-tional facies in Paleogene Yacheng formation,itwas determined that its development was con-trolled by the relative sea-level changes,tectonics,paleotopography and sedimentation and subsidencerates,and its development model was built.Fur-thermore,the spectrum imaging technique wasused to identify the coal-measure intervals in theresearch area,and three specific zones can be con-sidered as the areas where the rich source rock ofoceanic-continental transitional facies has devel-oped,i.e.the gentle slope between Lingshui low-uplift and the southeast margin of Lingshui depres-sion,the gentle slope between Songnan low-upliftand the southwest margin of Songnan depressionand the west plunging end of South ridge in Song-nan low-uplift.