91 / 2023-07-13 16:41:38

松辽盆地梨树断陷深部致密砂岩储层成岩演化过程

梨树断陷、营一段、致密砂岩、成岩作用、成岩演化

Abstract

The diagenetic evolution process of deep reservoirs in Lishu fault depression of Songliao Basin (buried depth >4000m) is not clear, which restricts the evaluation and prediction of deep high-quality reservoirs. In this paper, X-ray diffraction (XRD), scanning electron microscopy (SEM) and casting thin section analysis were carried out on the tight sandstone reservoir samples from the first member of the Lishu fault depression, and the characteristics and diagenetic evolution process of deep tight sandstone reservoir were studied. The results show that the first member of deep Ying Formation is mainly composed of feldspar lithic sandstone and lithic feldspar sandstone. The rock mineral composition is mainly feldspar, and the content of illite is the highest in the clay mineral composition. The deep tight sandstone reservoir space is a combination of pores and microfractures, and the pores are mainly secondary pores. Combined with the burial evolution history, the diagenetic evolution process of the first member of Deep Ying Formation includes: （1）Early compaction；（2）early calcite cementation、siliceous cementation、thin film cementation of clay minerals、turbidite cementation；（3）diagenetic compaction、tectonic rupture；（4）local feldspar and lithic dissolution：（5）secondary enlargement of quartz、lamellar calcite cementation、calcite metasomatism：（6）dissolution of clastic mineral particles and cements. Among them, compaction and hydrochloride cementation are the main types of diagenesis that affect the densification of sandstone reservoirs, and dissolution is the main type of diagenesis that improves the physical properties of deep tight reservoirs.

Key words：Songliao Basin；Tight sandstone；Reservoir characteristics; diagenesis



摘  要

松辽盆地梨树断陷深部储层（埋深>4000m）成岩演化过程不明确，制约了深部优质储层评价和预测。本文针对梨树断陷深部营一段致密储层样品开展了X射线衍射（XRD）、扫描电镜（SEM）和铸体薄片分析，开展了深部致密砂岩储层特征及其成岩演化过程研究。结果表明，深部营一段致密储层以长石岩屑砂岩和岩屑长石砂岩为主。岩石矿物组分以长石为主，粘土矿物组分中伊利石含量最高。深部致密砂岩储集空间为孔隙+微裂缝组合，孔隙以次生孔隙为主。结合埋藏演化历史，深部营一段储层成岩演化过程包括：（1）早期压实作用；（2）早期方解石胶结、硅质胶结、黏土矿物以薄膜状胶结、浊沸石胶结；（3）成岩压实、构造破裂作用；（4）局部长石、岩屑溶解；（5）石英次生加大、连片状方解石胶结、方解石交代作用；（6）碎屑矿物颗粒及胶结物溶蚀作用。其中，压实作用和盐酸盐胶结作用是影响砂岩储层致密化的主要成岩作用类型，溶蚀作用是改善深部致密储层物性的主要成岩作用类型。