二连盆地下白垩统发育一套陆源碎屑与碳酸盐矿物组成的混合沉积物，近年来在其中发现大量油气显示。通过岩心观察、薄片鉴定、物性分析和岩石热解等方法，综合研究了云质岩储集层的岩石学特征、储集空间类型、物性特征和成藏主控因素等。研究认为，云质岩储集层孔隙度高、渗透率低，属于低渗透-致密储集层，溶蚀作用或构造作用产生铸模孔和构造溶蚀缝，形成云质岩的“甜点”区；高碳酸盐含量烃源岩和低渗透-致密储集层呈互层式展布，烃源岩成熟度低，生烃超压不发育，与优质烃源岩(TOC>2%)相邻储集层溶蚀孔隙发育，从而降低油气充注阻力，最有利于油气聚集成藏。%A set of mixed clastic-carbonate deposits are developed in the Lower Cretaceous Erlian Basin, and abundant hydrocarbon shows exist in the dolomitic rocks. According to core observation, microscopic identification, physical analysis and rock thermolysis, the dolomitic rocks is a kind of low permeable-tight reservoir with high porosity and low permeability, which has developed “sweet points” with mold holes and structural corroded fissures generated by dissolution or tectonism. It is concluded that source rocks with high carbonate content are located near the low permeable-tight dolomitic rock reservoirs and lack hydrocarbon-generating abnormal high pressure due to the lower maturity;nevertheless, the high-quality dolomite mudstone (TOC>2%) is conducive to the formation of dissolution pores in the adjacent reservoir and the reduction of oil filling resistance, providing good conditions for oil accumulation of the proximal source type.
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