塔里木盆地志留系沉积体系及分布特征

根据现代沉积学和层序地层学理论 ,对塔里木盆地志留系大量的岩心、测井和地震资料进行了综合研究。结果表明 ,研究区志留系可以划分成 2个沉积层序 ,又可分为 3个沉积体系 :(1)发育较高成分和结构成熟度的冲洗层理和前积序列的滨岸沉积体系 ;(2 )生物扰动构造发育的砂泥岩不等厚间互的滨外陆棚和斜坡沉积体系 ;(3)具平缓地势缺乏障壁岛的碎屑潮坪沉积体系。详细分析了这些沉积体系的岩性序列、沉积构造及粒度概率等沉积特征 ,建立了研究区碎屑海岸和碎屑潮坪沉积模式 ,确定了不同沉积相的平面分布规律。结果显示满加尔坳陷草 1井区为盆地的沉积中心。根据该区沉积相与生储盖层之间的关系 ,探明了塔北南斜坡滨岸砂岩和塔中北斜坡砂坪砂岩是今后勘探的有利地区。

Characteristics and distribution of depositional systems of Silurian in Tarim basin

In order to determine sedimentary facies types and their distribution in Tarim basin, based on the recent sedimentology and sequence stratigraphy, a lot of coring data, well logging and seismic data from Silurian in Tarim basin were comprehensively studied. The Silurian of study area was divided into two types of sedimentary sequences. It mainly developed offshore depositional system with high maturities of content and texture, swash bedding and prograted sequence, and also developed a shelf and slope depositional system with a plenty of bioturbation structure and alternating sandstone mudstone. But it lacked the clastic tidal flat depositional systems with the plane and barrier bar. The sedimentary characteristics and distributions of the above depositional systems were analyzed. The sedimentary models of clastic coast and tidal flat were found. The sedimentary center of Silurian was determined at the Manjiaer depression. The transgression direction was from east to west in Tarim basin. The relations of deposional systems with source rock, reservoir and capping bed show that the sandstones in the southern slope of Tabei uplift and the northern slope of Tazhong uplift are the faverable exploration targets.