未成熟油藏的储层成岩作用

RESERVOIR DIAGENESIS IN IMMATURE OIL-POOL

金湖凹陷西园－崔庄地区阜二段储层（不论是生物粒屑灰岩还是砂岩）的成岩作用及其孔隙结构都与其含油性关系密切。含油的储层成岩作用浅、物性好、孔喉大、孔隙连通性好；不含油的砂岩和灰岩碳酸盐胶结和颗粒次生加大作用明显加强，物性和孔隙结构差，基本上失去了储集性。由该区的油气成因模式发现，未熟油的生成和聚集时间早（相当于早成岩Ａ亚期与Ｂ亚期的过渡期），较早进入储层的油气抑制了进一步的胶结、颗粒加大等作用，使其仍保持着早成岩Ｂ亚期初期的物性和孔隙结构。储层性质受控于成岩演化，又受控于油气聚集和断块差异活动。

Diagenesis and pore-constructure of biograin limestones or sandstones keep close relationship with the oil accumulation in the Xiyuan-Cuizhuang area of Jinhu depression.The oil-bearing reservoirs with high storage capacity had some large porethroat and good connection in the pores. The limestones and sandstones without oil were obviously strong in calcite cementation and grain growing. so they had poor storage property and pore-constructures. and even lost storage capacity. The oil generation and accumulation in the area showed that the discovered oil was immature one generated and accumulated in early time. The accumulated oil restrained further cementing and grain growing in the reservoirs occupied earlier by the immature oil.The reservoirs kept the petrophysical and pore-constructure features of those at the start of the B-subperiod of early diagenetic stage. Storage capacity of reservoirs was controlled by their diagenetic evolution. and the diagenesis is controlled by early hydrocarbon migration and accumulation as well as differential activity of fault trans.