齐家—鸳鸯沟地区5条主要断裂对沙二段的控藏作用

CONTROLLING ACTIONS OF 5 MAJOR FAULTS ON THE HYDROCARBON ACCUMULATION OF MEMBER Es_2 IN QIJIA-YUANYANGGOU REGION

在断裂发育及其演化特征研究的基础上,通过断裂与油气分布及成藏条件之间关系的分析,研究了齐家—鸳鸯沟地区的5条主要断裂对沙二段油气成藏的控制作用。结果表明:f_1、f_2断裂直接连接了东侧深部洼槽的沙三段、沙四段源岩和上覆西侧的沙二段,是油成藏的主要输导通道,f_3、f_4、f_5断裂仅对沿不整合面或砂体侧向运移油气起输导作用;5条主要断裂在沙二段发育多个转换带,转换带处发育的砂体为油气成藏提供了储集砂体;5条主要断裂侧向封闭能力强,为油气成藏提供了遮挡条件;f_3、f_4、f_5断裂成藏期后活动强度小,附近有油气聚集,而f_1、f_2断裂活动强度大,附近无油气聚集。

Based on the studies of the fault development and their evolution characteristics, by means of the analy- ses of the relationships between the faults and petroleum distributions and accumulation conditions, the researches of the controlling actions are conducted for five major faults in Qijia-Yuanyanggou region on Member Es2 hydrocar- bon accumulation. The achievements show that Fault fl and f2 directly connect the source rocks in Member Es3 and Es4 in the deep trough of the east side and Member Es2 in the west side, they are the main conducting channels for the oil accumulation, Fault f3, f4 and f5 only play conducting roles in the lateral migration of the oil and gas along the plane of the unconformity or sandbodies; a plurality of the transferring belts are developed for the five major faults in Member Es2, the sandbodies developed in the belts provide the reservoir sandbodies for the oil and gas ac- cumulation; the lateral sealing abilities of the five major faults are pretty strong, thus the barriering conditions for the hydrocarbon accumulation are proved ; the late activity strengths of Fault f3, f4 and f5 are weak after the enrich- ment, thus the petroleum is accumulated nearby, while the strengths of Fault fl and f2 are rather strong, so there is no hydrocarbon accumulated around.