白云深水凹陷成藏体系划分与成藏模式

Division of petroleum accumulation systems and study on accumulation patterns in Baiyun deep-water sag

通过对白云深水凹陷原油地球化学特征的系统研究,结合断裂展布、沉积和构造等地质要素,以成藏体系划分原则为理论依据,将研究区划分为北部番禺低隆起带成藏体系和东部流花—荔湾带成藏体系2大类,其中,北部番禺低隆起带成藏体系可进一步分为N1,N2,N3和N4共4小类,东部流花—荔湾带成藏体系可进一步分为E1,E2和E3共3小类。根据沉积环境、油源、原油成熟度、油气运聚主导因素等,总结出白云深水凹陷各成藏体系特征,并提出3种具有代表性的成藏模式,即开放式、封闭式和复式成藏模式。其中,开放式成藏模式的断裂非常发育,对油气运移和聚集具有重要作用;封闭式成藏模式的油气演化达到高成熟阶段,已热裂解成天然气,断裂、构造脊和砂体是其油气运移输导通道;复式成藏模式为晚期断裂、底辟带和构造脊共同控制油气成藏,其油气演化程度较高,已热裂解成天然气。北部番禺低隆起带N2,N3,N4成藏体系和东部流花—荔湾带E2,E3成藏体系均为有利油气运聚区。

From the point of geochemistry,and combined with such geological elements as fracture distribution,sedimentary and tectonic conditions,according to accumulation systems classification principles,the Baiyun deep-water sag is divided into two broad classes,seven small classes of accumulation systems,that is,four accumulation systems in Panyu lower uplift in the western part and three ac-cumulation systems in Liuhua–Liwan district in the eastern part.We summarize the respective characteristics of different accumula-tion systems based on the following classification properties: sedimentary environment,crude oil classification,material source,oilsource,crude oil maturity,oil and gas migration and accumulation,migration dominant factors.Three typical kinds of accumulation pat-terns are put forward on the basis of accumulation systems division,namely,open,closed and complex accumulation pattern.The openaccumulation pattern has the features of multiple and developed faults,the faults play an important role in oil and gas migration and ac-cumulation.The closed accumulation pattern is characterized by oil evolving into high maturity stage and cracking into gas thermally,fractures,ridge-like structures and sands are oil and gas migration channels.The complex accumulations are controlled by faults,dia-pir zones and ridge-like structures,high-degree evolution of petroleum cracking into gas thermally.According to the accumulation sys-tems division in Baiyun deep-water sag,and the comprehensive analyses of three kinds of accumulation patterns,it indicates that,theN2,N3,N4 andE2,E3are favorable migration and accumulation are as with good exploration prospects.