Sedimentary characteristics and genetic mechanism of the giant ancient pockmarks in the Qiongdongnan Basin,northern South China Sea

In the late Miocene,giant ancient pockmarks,which are fairly rare globally,developed in the Qiongdongnan Basin.In this paper,to determine the sedimentary characteristics and genetic mechanism of these giant ancient pockmarks in the Yinggehai Formation of the Qiongdongnan Basin,based on high-resolution 3D seismic data and multiattribute fusion technologies,we analyzed the planar distribution and seismic facies of the ancient pockmarks and compared the characteristics of the ancient pockmarks with those of channels,craters,and hydrate pits.Moreover,we also discussed the implications of the fluid escape system and paleo-bottom current activity in the ancient pockmark development area and analyzed the influence of the ancient pockmarks on the paleoclimate in this region.Finally,an evolutionary model was proposed for the giant ancient pockmarks.This model shows that the giant ancient pockmarks in the southern Qiongdongnan Basin were affected by both deep fluid escape and lateral transformation of paleobottom currents.In addition,the giant ancient pockmarks contributed to the atmospheric CO_(2)concentration in the late Miocene and played a great role in the contemporary evaluation of deepwater petroleum exploration.

富满油田古海底麻坑地质模式建立

针对富满油田主干断裂间和台缘滩深层的麻坑,在对三维地震资料进行精细解释的基础上,结合富满油田钻井和地震综合解释等资料,建立了麻坑的地震地质模型,通过改变麻坑发育规模及裂缝发育密集程度等因素,模拟分析富满地区古海底麻坑的地震响应特征变化,总结并建立了富满地区麻坑的地震识别模式以及麻坑分布、成因及其油气潜力,为富满地区奥陶系古海底麻坑储集层的有效预测提供依据。