柴达木盆地英西地区页岩油储层特征及有利区优选

为研究柴达木盆地英西地区古近系页岩油储层特征,开展了储层岩石学特征、物性及储集空间类型、含油性、源储配置关系等分析,并优选了有利储层发育区。结果表明:①英西地区下干柴沟组上段储层的岩石矿物包括碳酸盐、陆源碎屑、泥质及各种盐类矿物,混积特征明显;②综合地质和测井响应特征将研究区储层划分为3类,分别为层状泥页岩或泥质碳酸盐岩、块状泥页岩或泥质碳酸盐岩、斑状泥页岩或泥质碳酸盐岩储层;③储层主要储集空间类型包括晶间孔、粒间或晶间溶蚀孔、角砾孔洞和裂缝,物性总体偏低,孔隙度多为4%~6%,渗透率多为0.05~0.10 mD;④油气藏具有“源内成藏、整体含油”的特征,目的层含油丰度受控于物性和烃源岩的配置关系。该研究成果对英西地区页岩油勘探具有指导作用。

Shale oil reservoir characteristics and favorable area optimization in Yingxi area,Qaidam Basin

In order to understand the characteristics of Paleogene oil shale reservoirs in Yingxi area of Qaidam Basin, the petrological characteristics,physical properties,reservoir space,oil-bearing properties and source-reservoir occurrence relationship were analyzed,and favorable reservoir development areas were optimized. The results show that:(1)mineral compositions of reservoir-rocks in the upper member of Xiaganchaigou Formation demonstrate typically mixed features,including carbonates,terrigenous clastic,argillaceous and evaporite minerals. (2)According to the comprehensive geological and logging responses characteristics,the reservoirs in the study area were divided into three types, including laminated shale/argillaceous carbonate reservoirs, massive shale/argillaceous carbonate reservoirs and phenocrystal shale/argillaceous carbonate reservoirs.(3)The main pore spaces in reservoirs include inter-crystal pores,intergranular/inter-crystal dissolved pores,inter-breccia pores and fractures. In summary,the physical properties of reservoirs are nor good,their porosities range from 4% to 6% and permeabilities range from 0.05 to 0.10 mD.(4)The reservoir is characterized by "intra-source accumulation and wholebody oil-bearing",and the oil-bearing abundance of the target layer is controlled by reservoir properties and its relationship with the source rocks. This study results have a guiding role for shale oil exploration in Yingxi area.