沿层相干技术能够客观反映某一特定时期断裂的平面展布。利用高精度沿层相干技术对珠江口盆地白云凹陷南缘三维研究区断裂特征进行分析,加深了对白云凹陷构造特征的认识。分析结果表明:下渐新统恩平组顶面(T70)为区域不整合面,恩平组顶面以下以北东向断裂活动为主,在早渐新世停止活动;而恩平组顶面以上以北西向断裂活动为主,从始新世到中新世皆有活动。白云凹陷的断陷期结束于渐新世早期,之后长期表现为坳陷的特征。从研究区断裂与构造演化特征推断,下渐新统恩平组顶面(T70)为白云凹陷的断坳转换界面,对白云深水区沉积演化与油气成藏具有重要意义。
The coherence technique can objectively describe the plane distribution of the fault system developed in a special period. This paper introduces how the coherence technique is used to analyze the faulting characteristics within the 3D study area at the south margin of the Baiyun sag, the Pearl River Mouth Basin, in order to further understand the structural features of the Baiyun sag. The analysis results indicate that the Lower Oligocene Enping Formation top (T7~) is a regional unconformity, below which NE faulting activity was dominant and stopped in the Early Oligocene, and above which NW fault activity was dominant and kept active from the Eocene to the Miocene. The faulting stage of the Baiyun sag ended in the early Oligocene, and then the depression characteristics was kept for a long term. The faulting and structural evolution within the study area reveals that the Lower Oligocene Enping Formation top (T7~) is the fault-depression transition interface in the Baiyun sag, which is significant for sedimentary evolution and hydrocarbon accumulation within the deepwater area in the sag.