准噶尔盆地沙南地区二叠系梧桐沟组重力流沉积

GRAVITY FLOW SEDIMENTS IN WUTONGGOU FORMATION OF PERMIAN IN SRA'NAN, JUNGGAR BASIN.

沙南油田主要储油层为上二叠统梧桐沟组重力流沉积，以砂砾质高密度浊流为主，间夹有低密度浊流、碎屑流和颗粒流。顶部转化为扇三角洲沉积。主要岩石相类型为正递变砂砾岩、块状砾岩和块状砂岩，其次为粗尾递变砂砾岩、牵引毡砂砾岩、混杂组构砂砾岩和经典浊积岩。正递变砂砾岩、块状砾岩和块状砂岩是主要的含油岩石相。混杂组构砂砾岩是引起油层内部非均质性的主要岩石相。油田的优质储集层微相区为中扇亚相的辫状水道砂砾岩和水道间砂岩。沙南浊积扇经历了发育期、全盛期和衰亡期三个阶段，每个阶段又经历了扇体面积由大变小、颗粒由粗变细的演变过程。

Gravity flow deposit in Wutonggou formation of Permian are the main reservoir in Sha'nan area in Junggar basin, which are dominated by sandy-pebbly high-density turbidity current, occasionally interbeded with low-density turbidity current, clastic flow and grain flow. The lithologic factes is mostly sandy-conglomerate, massive conglomerate and massive sandstone, with less wide-tail Sandy-conglomerate, traction flow sandy-conglomerate, mixing fabric sandy-conglomerate and classic turbidite factes. The braided channel sandy-conglomerate and intra-channel sandstone in middle-fan subfacies are the high-quality reservoir microfacies zone. The turbidite fan in Sha'nan area has nudergone three stages: growing period, flourishing period and perishing period, and in each stage the fan becomes smaller with finer grain.