坪北油田长4+5、长6油组短期基准面旋回层序分析

Analysis of Short Term Datum Cyclical Sequence of Chang 4+5 Formation and Chang6 Formation in Pingbei Oilfield

运用高分辨率层序地层的短期基准面旋回原理,根据短期基准面旋回界面的识别标志将坪北油田长4+5、长6油组短期基准面旋回层序划分为向上“变深”的非对称旋回(A)、向上变浅的非对称旋回(B)、向上“变深”复变浅的对称旋回(C)等三种基本结构类型。论述了每个基本类型的沉积背景、叠加样式、岩性组成和沉积动力学过程。在此基础上,总结了短期基准面旋回层序的变化规律和分布模式,并指出短期基准面旋回层序的研究意义。

The short term datum cyclical sequence of Chang 4+5 Formation and Chang 6 Formation in Pingbei oilfield can be divided into 3 basis structural types according to short term datum cyclical sequence theory for formation with high resolution and based on identification marks of short term datum cyclical interface. They include: upward “deeper” antisymmetrical sequence (A), upward more shallow antisymmetrical sequence (B) and upward “deeper” and then more shallow symmetrical sequence (C). The sedimentary environment, superposition styles, lithology and sedimentary dynamic process of these 3 types are discussed in this paper. The changing rules of short term datum cyclical sequence and distribution modes are generalized, and the significance of research on short term datum cyclical sequence is also established in this paper.