松辽盆地古龙页岩油甜点特征及分布

Characteristics and distribution of sweet spots in Gulong shale oil reserviors of Songliao Basin

松辽盆地北部页岩油资源丰富,落实甜点资源、空间分布及富集因素意义重大。利用宏观岩心精细描述、微观实验分析,开展了古龙页岩油甜点储集性、含油性、流动性、可压性研究。在“四性”评价基础上,初步分析了影响甜点的主控因素。结果表明:古龙页岩油具有储集性能好、含油丰富、地层压力高、原油密度低、原油黏度小、较高的气油比等特点;高有机质层状和纹层状页岩发育、高成熟热演化和较高的地层压力是古龙页岩油富集高产的主要控制因素。纵向上,甜点层主要发育在青一段及青二段下部,根据岩相组合类型、含油特征可分为上、中、下3个甜点段,其中下甜点段发育优质甜点层,横向分布稳定。平面上,甜点区主要分布在齐家—古龙地区。目前齐家—古龙地区下甜点段试油已得到证实,是勘探开发最有利目标区和甜点靶层。

The reservoirs in the northern of Songliao Basin are rich in shale oil resources,so it is of great significance to define the resources,spatial distribution and enrichment factors of sweet spots there.With the help of macro-core fine description and micro-experimental analysis,the study on the reservoir property,oiliness,mobility and compressibility of sweet spots of Gulong shale oil was carried out.On the basis of the evaluation of“four-property”,the main controlling factors of sweet spots was preliminary analyzed.The results show that Gulong shale oil is characterized by good reservoir property,high oil content,high formation pressure,low density,low viscosity and high gas oil ratio etc.The main controlling factors for the enrichment and high yield of Gulong shale oil include well-developed rich-in high organic matter layered and laminated shale,high mature thermal evolution and higher formation pressure.Vertically,sweet spots are mostly found in the first member and lower part of the second member of Qingshankou Formation,which is divided into the upper,middle and lower intervals in terms of lithofacies combination types and oil-bearing features,in which the high-quality sweet-spot layers with stable lateral distribution are developed in the lower sweet-spot interval.On the plane,sweet-spot area is mainly developed in Qijia and Gulong area.At present,the oil testing result has confirmed that the lower sweet-spot interval in Qijia and Gulong area is the most favorable target area and the sweet-spot target layer for exploration and development.