Abstract:

 Donghe Sandstone was deposited in the early stage of sea transgression from the end of Devonian to the early stage of Carboniferous, Donghe sandstone is not an isochronous stratum with various depositional ages in different areas. As a kind of broadly-developed deposits in the early stage of transgress, Donghe sandstone has an outstanding feature of fill and level up. The important controls of the development of depositional facies are the transgress speed, the sediment supply and the pre-transgression paleo-relief. In northern Tarim Basin, blocked by the Tabei paleo-uplift, seawater stayed around the paleo-uplift for a long period, which, combined with the coarse-grained sediment supply, promoted the development of shore beach deposits. In central Tarim Basin, however, the deposit types are diversiform with the complex topography background. Fluvial deposits developed in the bottom conglomerate section, and estuary and shore beach deposits in the massive sandstone section and the sandy conglomerate section. Different section has its own characteristics of grain component, grain selectivity and grain size. While in the other gently-slope and flat areas, rapidly-deposited shore and shelf sediments developed during the transgressive period. Controlled by the depositional environment, the effective reservoir of Donghe Sandstone distribute regionally. Beside the depositional factor, the low paleo-geothermal gradient and the short-term deep-burial history are the other two crucial controls of the development of the high-quality Donghe Sandstone reservoir.

摘要：

东河砂岩是一套海侵初期的沉积产物，东河砂岩不是一个等时沉积体，相当于晚泥盆世晚期至早石炭世早期沉积，具体沉积时间各地有差异。由于东河砂岩是覆盖广泛的海侵初期沉积，因此具有海侵初期填平补齐的特征，其沉积相决定于海侵的速度、沉积物的供给和海侵前的古地貌。塔北地区受塔北古隆起的阻挡，海水在古隆起周围滞留时间较长，又有较粗粒的物源供给，其沉积产物主要是滨岸海滩沉积；塔中地区由于地形复杂，沉积类型也比较复杂，底部砾岩段有河流相沉积，而块状砂岩段和砂砾岩段有河口湾和滨岸海滩沉积，不同段在成分、分选性和粒级上有较大的差异；而其它低平地区主要是海侵期快速的滨岸和陆架沉积。受沉积因素影响，东河砂岩有效储层的分布具有地域性；除沉积因素外，低的地温梯度和短期的深埋藏是优质储层发育的重要控制因素。