南海珠江口盆地深水扇系统的发现

深水扇系统已成为近20年来国际石油产量与储量增长的主体.对南海珠江口盆地层序地层学的研究和分析发现,在盆地内面积最大、最具生烃潜力的白云凹陷发育有大批相互叠置的低水位深水扇.基于勘探与研究成果,通过剖析典型高分辨二维地震资料,证实白云深水凹陷是自30Ma以来古珠江水系的沉积中心,与全球海平面变化周期相协调.在对应的各个三级层序的低水位发展阶段形成深水沉积体系,并具备独特的地震相组合结构.深水扇系统广布于受同沉积断层控制的古陆架坡折带及其下倾方向.由富砂的古珠江孕育并叠置在巨厚的下第三系湖相烃源岩之上的深水扇系统具有良好的油气勘探前景.

Discovery of deep-water fan system in South China Sea

The deep-water fan systems played a dominate role for increment of the international oil production and reserves in the last 20 years.The Pearl River Mouth Basin (PRMB),located at South China Sea,is a Cenozoic passive continental margin rift basin with a great potential for oil and gas exploration.Sequence stratigraphy research and analysis show that there exist huge quantities of stacked low-stand fans in Baiyun Sag having the largest area and the most genetic potential in the PRM basin.Lots of research experiences and abundant exploration results from PRMB as well as the typical high-resolution 2D seismic information analysis proved that the Baiyun deep-water sag has been the depositional center of the ancient Pearl River water system since thirty million years before present.As the results of eustatic changes,the deep-water sedimentary systems with unique seismic face architecture were developed in the low-stand stages corresponding to the third order sequence.The deep-water fan systems were spread over paleo shelf-edge and controlled by growth faulting and its down-slope direction.It is concluded that the deep-water sand rich fan system,which overlies on the lower Tertiary lacustrine source rocks with great thickness,has a prospective future for oil and gas exploration.