珠江口盆地珠一坳陷断裂控藏定量表征与有利勘探区预测

摘要：珠江口盆地珠一坳陷中浅层珠海组、珠江组、韩江组的油气主要来自深部烃源岩层系，断裂既是必备的油源通道又对油气藏形成和分布起到关键作用。为明确断裂对珠一坳陷珠海组-韩江组油气成藏的控制机制，对断裂分布及演化特征进行了分析，依据断裂活动时期和断开层位的不同将其分为5类：早期活动-深层切割型断层、中晚期活动-中浅层切割型断层、晚期活化-深浅切割型断层、继承性活动-深浅切割型断层、通天型断层。在对恩平南断裂带解剖的基础上，发现影响断裂控藏的因素主要有断裂类型、断裂活动速率、断裂规模和圈闭离断裂的平面距离。针对全区所发现油藏，对以上影响因素进行统计分析，结果表明：研究区深浅切割类断层控藏作用显著，且其断层活动速率中等时最有利于油气成藏，在15 m/Ma左右达到最大；断裂规模越大，越有利于油气成藏；圈闭距控藏断裂越近，含油气性越好。根据活动速率、断裂规模、断裂与圈闭的相对距离所拟合的定量控藏表征公式，发现现今探明的978%的油气藏均分布在深浅切割型断裂控藏概率大于05的区域。依此指出惠东低凸起及惠北半地堑东南部、恩平中半地堑东北部为下一步有利勘探区。

Quantitative Evaluation of Control of Faults on Hydrocarbon Accumulation and Play Fairway Prediction in Zhu I Depression of Pearl River Mouth Basin

Abstract:The hydrocarbon in shallow groups including Zhuhai Formation,Zhujiang Formation,Hanjiang Formation in Zhu I Depression of Pearl River Mouth Basin mainly come from deeply buried source rock. The fault is oil source passage and plays an essential role in the formation and distribution of oil and gas reservoirs. In order to understand the control of faults on hydrocarbon accumulation in the Zhuhai Formation to Hanjiang Formation in Zhu I Depression of Pearl River Mouth Basin, fault distribution and anatomy of fault zone are studied. On the base of fault activity period and layer position broken by fault, different faults can be divided into five categories: early activity which cut deep, advanced activity which cut the shallow stratum, late activity which cut through deep and shallow strata, succession activity which cut through deep and shallow strata, bable type of fault. Based on the anatomy of the fault zone south of Enping, it is found fault controlling factors mainly include fault type, fault event rate, the size of the fault,and distance from the traps to fault. For the regions found reservoirs, the above factors are analyzed. The results show that: the fault that cut through deep and shallow strata controls hydrocarbon accumulation significantly. As the rate of fault activity is moderate, it is most favorable for hydrocarbon accumulation, which reach a maximum at 15 m/Ma; the larger the size of the fault is, the more favorable for hydrocarbon accumulation is; the closer the trap to the fault is, the better for reservoir hydrocarbon potential is. According to activity rate, fault scale and relative distance between trap and fault, an quantitative characterization of Tibetan formula is found out. It is found 978% of the current found oil and gas reservoirs are located in the probability of fracture controlled Tibetan region of 05. Southeastern Huidong low uplift and the north half graben, Enping in the northeastern part of the half graben are favorable areas of fracture controlled zone.