扇三角洲相高分辨率层序地层研究——以克拉玛依油田百21井区克上组油藏为例

摘要

In order to recognize the characteristics of fan delta facies reservoir and improve the reservoir description accuracy, this paper carried out the study on the reservoir of Upper Karamay Formation based on high resolution sequence stratigraphy and the strata cyclicity as well as sedimentology response caused by different grade base level change. The Upper Karamay Formation in Bai-21 well area can be divided into one long-term sequence cycle, two middle-term sequence cycles, 14 short-term sequence cycles and 33 -37 super-short-term sequence cycles. The shortterm sequence cycles can be divided into two basic structure types which are up-deepening asymmetry and upshallowing asymmetry. The sedimentary sequence, structure type, stacking pattern and distribution pattern of supershort-term sequence cycles in the process of base level change were discussed in detail. The sequence stratigraphic framework was built up by making short-term sequence as isochronous stratigraphic correlation unit. The sedimentary characteristics of sand body and the oil-gas distribution were analyzed. All these studies provide a good foundation for reservoir research and later development of Upper Karamay Formation in the Bai-21well area.%为深入认识扇三角洲相储层特征，提高油藏描述精细程度，文中以高分辨率层序地层学理论和技术方法为指导．依据不同级次基准面的升降运动所导致的地层过程旋回性和沉积学响应特征．将百21井区克上组划分为1个长期旋回、2个中期旋回、14个短期旋回以及33-37个超短期旋回。其中短期旋回可划分为向上变“深”的非对称型和向上变“浅”的非对称型2种基本结构类型。详细讨论了基准面旋回变化过程中超短期旋回的沉积序列、结构类型、叠加样式以及分布模式，建立了以短期旋回层序为等时地层对比单元的全区层序地层格架，分析了格架内砂体的沉积特征和油气分布，为储层研究和油田后期开发奠定了基础。