摘要:
在岩心观察的基础上,通过对歧口凹陷马东东地区沙河街组一段下部岩石类型及其组合、沉积构造、粒度特征、地震和测井资料的处理成果以及岩心物性的研究,提出了该区为深湖环境下的重力流沉积,包括水道微相、漫溢微相、水道间微相和湖盆泥微相。其中,以水道微相为主。重力流沉积物源方向稳定,主要来自于研究区的北东方向,水道位置总体摆动不大。重力流砂体呈带状展布,厚砂体发育区位于Gs24-26井区附近及其以南的马东南地区。水道微相在滨Ⅰ油组分布最广,但分叉较多,其余3个油组重力流水道均以水道下游会合为主。该区沉积微相类型与砂岩厚度有密切的对应关系,而砂体越厚孔隙度越大。水道微相的储层物性最好,也是最有利的油气富集微相单元。通过研究,掌握了研究区沙一下沉积微相的时空展布和变化规律及其与储层物性的关系。
Abstract:
Based on core observation, the origins of the lower member in the first submember of the Shahejie formation in Madongdong area of Qikou sag are analyzed by using the data including rock types and their combinations, sedimentary structures, grain size, the results of seismic and logging, and reservoir properties.The reservoir in this area represents gravity flow deposits in the deep lake environment.Deposits consist of channel, overflow, interchannel and lake mud deposits.Gravity flow channel sediments in the study area mainly come from north east area.Channel position overall does not change too much. Gravity flow deposits show band distribution and the thicker sand bodys located near Well Gs24-26 area and Madongnan area.Overall, channel facies are most widely distributed in the BinⅠoil group, and bifurcated more.In the Ban Ⅱ, Ⅲ and Ⅳ oil group, gravity flow channels are mainly joined by channel downstream.There is close correspondence between microfacies types and thickness of sandstone, and the thicker sand body, the greater porosity.Waterways microfacies have the best reservoir properties, and is the most favorable oil and gas-rich facies unit.
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