凹陷不同构造区油富集主控因素及成藏模式——以松辽盆地三肇凹陷葡萄花油层为例

Main factors of oil enrichment and accumulation mode of depression different structure zones: In case of Putaohua reservoir of Sanzhao depression in Songliao Basin

分析松辽盆地三肇凹陷不同构造区油藏类型和油水分布规律。结合有效源岩控范围、油源断层控通道、构造样式控部位、沉积演化控层位和单一圈闭控规模等油富集条件分析,提出凹陷不同构造区油聚集机制受控于不同构造背景下的断层与砂体匹配样式,最终建立凹陷分区成藏模式。研究结果表明:源内向斜区主要发育受断层密集带背形构造、油源断层短距离垂向输导和高孔渗分流河道选择性充注匹配控制的窄带状岩性油藏;近源鼻状构造区主要发育受继承性鼻状构造隆起和油源断层近距离侧向输导匹配控制的连片状构造-岩性油藏;源外斜坡区主要发育受断阶带高点、"断-砂"桥连式远距离侧向输导、断层侧向封闭性和岩性上倾尖灭控制的宽带状断层-岩性油藏和岩性上倾尖灭油藏。凹陷分区成藏模式为源内向斜区"T型"运聚成藏模式、近源鼻状构造区"犁式"运聚成藏模式和源外斜坡区"断阶状"运聚成藏模式。

The type and distribution of oil reservoirs in different construction zones of Sanzhao depression of Songliao Basin were analyzed. In combination with analysis on effective source rock control range, oil source fault control channel, structural style control site, sedimentary evolution control of stratigraphy and single trap control of the scale of oil enriched condition, the oil gathered of depression different tectonic zones mechanism controlled by the context of different tectonic fault and sand body matching styles was proposed, and a depression partition forming pattern was established. The results show that inside source within the syncline area is mainly developed by faults with a back shaped condense faults belt, short distance of oil source faults separation vertical conduit and high porosity and permeability distributary channel selective filling matching control of narrow shape lithologic reservoir; Nose structure near the source area is mainly developed by the inherited structural nose uplift and lateral oil source faults separation close the connection conduit matching control patch structure-lithologic reservoir; Outside source of the slope mainly developed by the fault zone highs, ＂Broken-Sand＂ bridging formula distant lateral conduit, broadband-like fault-lithologic and lithologic reservoir updip pinch controlled by faults lateral seal ability and lithology updip pinch-out. The depression partition forming patterns are the inside source within the syncline area ＂T-type＂ migration and accumulation mode, nose structure near the source area ＂plow＂ migration and accumulation mode and outside source the slope area ＂stepped down＂ migration and accumulation mode.