箕状断陷缓坡带油气成藏模式——以歧北斜坡为例

Research on hydrocarbon accumulation models of gentle slope belt of half graben-A case study of Qibei slope belt

箕状断陷缓坡区面积大,坡度缓;砂体远源输送,分选好,物性好;油气近源充注、供油面积大;成藏条件优越。歧北斜坡为大面积多阶挠曲缓坡,受孔店、港西和燕山物源波及,以辫状河三角洲和远岸水下扇为主体的多种类型砂体叠置于多阶斜坡之上,形成满坡含砂的格局。中、低斜坡位于古近系有效烃源岩范围内,近源-源内复式联合疏导,具有"两期充注、先油后气、差异聚集、高油低气"的特点,形成多层系岩性地层油气藏大面积叠置连片分布,是勘探的最有利靶区。

The area in gentle slope belt of half graben has a big area and a gentle slope belt.The sand bodies from far source has the characteristics of big sorting and good physical properties,while the sand bodies from near source has the characteristics of big drainage area and superior hydrocarbon accumulation conditions.The Qibei slope belt has the characteristics of big area and multi-stages.Influenced by the sources in Kongdian,Gangxi and Yanshan,various sand bodies such as braded delta and offshore subaqueous fans were superimposed on multi-stages slope,forming the pattern of full slope sand.The middle,lower slopes are located among the Paleogene effective source rock,with the characteristics of ' two-phase infilling,first oil second gas,differ-ential accumulation and upper oil lower gas ', forming the most favorable target exploration area with contiguous distribution and big superimposed area of multilayer systems of lithologic-stratigraphic reservoirs.