二连盆地砂岩体形成和分布的多元控制特征分析

二连盆地砂体形成和分布受多种因素控制,主要包括构造带类型、同沉积断层、沉积体系域、坡折带类型和沉积相类型。不同构造带类型发育不同沉积体系的砂体,同一构造带不同类型构造上发育的砂体类型也不同。陡坡带与缓坡带边界断层的断层面产状和断层组合控制着物源注入方向。低位体系域、湖侵体系域和高位体系域分别发育不同沉积体系的砂体。二连盆地不同类型的坡折带上发育不同沉积相类型和不同形态的砂体;不同类型沉积相对砂体的特征具有重要的控制作用。据此,本文提出了“多元控砂”概念,并认为“多元控砂”可以概括二连盆地岩性圈闭形成和分布的复杂性。

ANALYSIS ON CHARACTERISTICS OF MULTI-FACTOR CONTROLLING SAND-BODIES' FORMATION AND DISTRIBUTION IN THE ERLIAN BASIN

In the Erlian Basin, the main controlling factors on formation and distribution of sand-bodies included structural zone types, syndepositional faulting, systems' tract, slope-break belt types, and sedimentary facies types. The different types of sand-bodies developed not only in the varied structural zones, but also in the different structures of the same structural zone. The occurrence of fault surface and combination of boundary faults in the steep or gentle slope zones controlled the injecting directions of detrital sediment source. The sand-bodies of the different sedimentary systems formed in the different systems' tracts, respectively. The different sedimentary facies and morphological features of sand-bodies existed in different slope-break belts, and the different types of sedimentary facies affected the characteristics of sand-bodies. To sum up, this paper put forward a concept of "multi-factor controlling sand-bodies", and based on some examples from the Uliastai Sag, Jargalangt Sag, Bayan Dulan Sag, Anan-Abei Sag and Saihan Tal Sag of the Erlian Basin, the formation and distribution of sand-bodies controlled by these factors were discussed detaily. Furthermore, the paper thought that the concept of "multi-factor controlling sand-bodies" could reveal the complexity of formation and distribution of lithologic traps in the Erlian Basin.