复杂断块油藏残余地层格架的建立及油层细分方法

Establishment of residual stratum framework and its subdivision in complex fault block reservoirs

海拉尔盆地是大庆油田勘探开发的重点地区,由于该地区在地史时期内经历过多期强烈构造运动,使该断陷盆地分割性强,地层往往呈残余状态。应用陆相层序地层学原理和地震相、沉积相、岩石相及测井相研究资料,对海拉尔盆地贝尔凹陷南一段内部层序界面进行了识别,并对地层缺失层段进行了确定和恢复。结果表明,南一段沉积过程中经历了3次湖泛作用和1次沉积转换作用,相应地形成了3个稳定泥岩段及1个由进积到退积的沉积转换面。通过基准面旋回变化过程中沉积湖泛面和转换面的追踪对比所建立的南一段残余地层等时地层格架,可以使目的层段内的油层组划分对比具有等时性,所建立的标准剖面可用来有效识别不同成因类型的地层缺失和缺失厚度。

Hailar Basin is the key area of exploitation and development in Daqing Oilfield. The fault block basin has strong isolation, and it is difficult to make reservoir comparison for the existence of residual stratum formed by polyphase intense tectonic movements in geological history. Based on the study of seismic facies, sedimentary facies, lithofacies and log-facies of member 1 of Nantun formation of Beier depression in Hailar Basin, the inner sequence boundary was recognized and the missing stratum was determined and restored using continental sequence stratigraphy method. The results show that member 1 of Nantun formation was undergone three times pan-lake period and one time sedimentary transferring period in the sedimentary processes, as a result, three stable mudstone sections and a sedimentary transforming interface were formed, Each pan-lake surface and transforming surface was traced in the whole region using the theory of sequence stratigraphy, and made as the limit of reservoir comparison. The isochronous stratum screenwork of residual stratum in member 1 of Nantun formation was built. Using the standard section and sequence boundary characters, the missing stratum can be identified and the right stratum sequence of each well can be confirmed effectively.