松辽盆地陆相页岩油富集条件及勘探开发有利区

Enrichment conditions and favorable zones for exploration and development of continental shale oil in Songliao Basin

陆相页岩油是中国独具特色的非常规油气资源类型,已经成为中国石油增储上产的重要阵地。通过系统阐述松辽盆地古龙地区页岩油(古龙页岩油)的勘探开发历程,总结陆相页岩油富集成藏的地质条件,明确资源潜力,并指出古龙页岩油有利区及下一步勘探开发方向。研究结果表明:(1)古龙页岩油主要经历泥岩裂缝油藏、夹层型页岩油和页岩型页岩油3个勘探开发阶段;(2)古龙地区页岩为陆相淡水—微咸水湖盆成因,层状藻富集,形成了分布面积广、厚度大、生油能力强的富有机质页岩,奠定了古龙页岩油规模发育的物质基础;(3)古龙地区页岩发育大量微米—纳米级有机质生烃缝、孔隙和天然裂缝,为页岩油提供富集空间和渗流通道;(4)古龙页岩油热演化程度高,有机质大量生油,原位超压保存,地层能量充足,有利于页岩油的开发动用;(5)古龙页岩油顶、底板岩性致密,断层封堵性好,为古龙页岩油大规模连片分布提供宏观保存条件;(6)古龙页岩油有利区分布面积为1.46×10^(4)km^(2),为大规模连续分布的超压页岩油藏,资源量巨大,石油资源量为(100~150)×108t,齐家—古龙凹陷轻质油带和三肇凹陷内部地质条件优越,试油井产油效果好,是目前勘探开发的核心区。

Continental shale oil is a unique type of unconventional oil and gas resource in China,and has become an important field for increasing oil reserves and production in our country.By systematically elaborating the exploration and development history of Gulong shale oil in Songliao Basin,the paper summarizes the geological conditions for the enrichment and accumulation of continental shale oil,clarifies the resource potential,and points out the favorable zones for Gulong shale oil and the direction of further exploration and development.(1)Gulong shale oil mainly went through three exploration and development stages,i.e.,mudstone fractured reservoir,interlayer-type shale oil and shale-type shale oil.(2)Gulong shale was originated from continental fresh water or brackish water lake basin,where lamellar algae were enriched,thus forming the organic-rich shale with wide distribution,large thickness and strong oil generation capacity.This lays the material foundation for the scale development of Gulong shale oil.(3)Gulong shale has a large number of micro-nano organic fractures for hydrocarbon generation,pores and natural fractures,providing the enrichment space and seepage channels for shale oil.(4)Gulong shale oil has a high degree of thermal evolution,and is generated in large amount from organic matters and preserved in-situ under overpressure,and the formation energy is sufficient,which are conducive to the development and production of shale oil.(5)Gulong shale oil has the roofs and floors with tight lithology and faults with good sealing characteristics,which provides macro preservation conditions for large-scale contiguous distribution of Gulong shale oil.(6)Gulong shale oil has the favorable zone of 1.46×10^(4)km^(2),which is a large-scale and continuous overpressure shale reservoir with the vast resources of(100-150)×10~8t.The light oil zone in Qijia-Gulong sag and the interior of Sanzhao sag are the core areas for exploration and development due to their superior geological conditions and good effects of oil well testing.