松辽盆地北部青山口组致密油特征及聚集模式

通过钻井、测井、岩芯及实验数据综合分析，对松辽盆地北部青山口组致密油特征与聚集模式进行了深入研究。结果表明，松辽盆地北部青山口组致密油分布在三角洲前缘及湖相区，储集层属于片状浊流形成的致密储层，孔隙度一般小于10%，局部可达到15%，渗透率普遍小于0.1×10-3 μm2。储集空间为粒间孔、粒内溶孔、铸模孔、微裂缝等，孔隙直径分布在5~200 μm，孔喉半径小于0.5 μm。烃源岩是青山口组一段和二段湖相泥岩，具有广覆式分布特点，干酪根为Ⅰ型或Ⅱ₁型，平均有机碳含量(TOC)为1%~3%，热成熟度(R_o)为0.9%~1.1%，属优质成熟烃源岩。聚集模式为储层平面上大面积连续分布，无明显边界，纵向上储层与源岩交互叠置形成千层饼状，具有紧密接触的源储共生型成藏组合。因此，致密油聚集宏观上受成熟烃源岩控制，其次取决于致密储层分布。致密油储层普遍超压，含油级别为油斑和油迹，不存在油浸和富含油，原油属于低黏度轻质原油，单井无自然产能，采取水平钻井并进行大规模分段体积压裂才能获得工业产能。对其沉积及聚集模式的认识为松辽盆地北部致密油勘探拓展了新的空间，具有实际指导意义。

A Study on Qingshankou Formation's Tight Oil Characteristics and Accumulation mode in the northern Songliao Basin

Through a comprehensive analysis of drilling, well logging, cores and experimental data, an in-depth study on the Qingshankou Formation's tight oil characteristics and accumulation mode in northern Songliao Basin was described and established.It is found that the unconventional reservoir is a densified reservoir which developed from platelike turbidity current in both deltaic front and lake facies region.The porosity of the reservoir is less than 10% in general, in some part the porosity could reach 15%, and the permeability is less than 0.1×10-3 μm2 in general.Reservoir spaces are intergranular pore, intragranular dissolved pore, mold pore, and microfracture.The diameters of pores range from 5~200 μm and the diameters of pore throat are less than 0.5 μm.The source rock is the lacustrine facies mudstone of the first and second Section in Qingshankou Formation, and that are typical of extensive distribution: kerogens are either type I or type II1, average TOC is 1%~3%, Ro is from 0.9%~1.1% and the rock attributes to mature high-quality source rock.Horizontally, the reservoir has some characteristics of facies belt and regional belt, but there is no obvious entrapment boundary.Vertically, the reservoir and the source rocks piled up alternatively and formed like flaky pastry, reservoir forming type is source-reserve impinge and mutualistic symbiosis.The oil bearing degrees of the reservoir are oil patch and oil stain.Oil immersion and oil-rich rocks do not exist, the crude oil belong to low viscosity and light crude.The reservoir does not have natural production, but a relatively high industrial capacity could be adopted in horizontal well by large-scale segmental bulk fracturing.Therefore, the study on platelike turbidite reservoir develops and accumulation mode develop new space for the tight oil exploration in Songliao Basin, and possess practical significance.