古地貌恢复方法及应用——以济阳坳陷桩西地区沙二段为例

济阳坳陷桩西地区沙二段埋深较大,应用残留厚度进行古地貌恢复存在较多问题。介绍了用压实法进行古地貌恢复的原理及方法。该方法分为视厚度校正、压实方程建立、单井压实厚度恢复、原始厚度图和古地貌图编制4个步骤。根据沙二段顶面构造图计算的真厚度校正系数最小可达0.83。压实结果表明压实率一般大于30%。结合视厚度校正、压实恢复结果和古水深,编制了沙二段基准面上升期和下降期的古地貌图,桩西地区沙二段古地貌中间高、东西两侧低。滩坝主要分布在孤北古隆起东西两侧,滩坝的发育明显受古隆起的控制。

Methods and Application of Paleo-geomorphologies Rebuilding: An Example of the Second Member of Shahejie Formation, Zhuangxi Area, Jiyang Depression

This study applied the principle and methods of compaction restoration for reconstructing paleo-geomorphology of the Second Member of Shahejie Formation in Zhuangxi area of Jiyang Depression. The analyzing processes include four steps: (1) correcting of apparent thickness; (2) establishing of compaction equations;(3) restoring compaction of formations in each single drilling well; (4) composing maps of thickness of original layer and paleo-geomorphology. As a result, the minimum value of correction coefficient for the real thickness was calculated as 0.83, based on structural map of the top of the Second Member of Shahejie Formation. The compaction rates are generally higher than 30%. Furthermore, the paleo-geomorphological maps of the Second Member of Shahejie Formation during uplift and subsidence sedimentary periods in Zhuangxi area were compiled. One highland in the middle and two sags in the eastern and the western sides of the Zhuangxi area were recognized from the maps. Beach bars occurred mainly along the two sides of Gubei paleo-uplift, suggesting the formation and development of beaches were clearly controlled by paleo-morphological uplift.