南黄海盆地崂山隆起构造特征与油气勘探方向

Structural characteristics and hydrocarbon exploration prospect of the Laoshan uplift in the South Yellow Sea Basin

  • 摘要: 崂山隆起海相地层作为南黄海盆地海相中—古生界油气勘探的新领域、新层系,将是下一步油气战略发现和勘探认识突破的方向。综合近年来详查勘探的地震解释成果,划分该隆起北部为青峰变形带,南部为高石稳定带。指出青峰变形带整体为逆冲和逆掩推覆体系,发育NE向逆断层;高石稳定带为弱变形稳定带,发育规模较小的NW向斜列断层。崂山隆起断裂走向有NE、NW和近EW向3组,边界断裂为近EW走向反转断裂。海相构造层变形具有北强南弱、西强东弱、上强下弱的特征。印支—早燕山期挤压推隆和晚燕山—喜马拉雅早期弱拉张/张扭作用下差异升降错断,形成了崂山断隆区,具有挤压、拉张、走滑和反转等4大构造样式。通过形成过程分析,揭示崂山隆起加里东期为古隆起;海西期为稳定地台;印支期可能为北部前陆盆地的前隆挠曲带,形成幅度增大的背斜;燕山早期为改造型断背斜;燕山中期崂山隆起基本定型;晚燕山—早喜马拉雅期隆升剥蚀,并发育局部小残凹;喜马拉雅晚期开始整体沉降。结合油气地质条件分析,认为崂山隆起南部的高石稳定带是海相油气勘探有利区带,海相下构造层(震旦系—志留系)变形改造较弱,是有利的油气勘探层系。

     

    Abstract: Meso-Paleozoic marine deposits widely occur on the Laoshan uplift of the South Yellow Sea Basin. As a new field and layer for oil and gas exploration, it shall be the future targets for strategic discovery of oil and gas and the breakthrough point of exploration understandings. Based on the detailed seismic interpretation results and exploration progress made in recent years, the uplift is divided into two parts, the Qingfeng deformation zone in the north and the Gaoshi stable zone in the south. The Qingfeng deformation zone is a cover-detachment overthrust nappe system characterized by NE trending thrust faults, while the Gaoshi stability zone a weak deformation and stable zone. NW trending synclinal faults are developed in small scale. The fault system of the Laoshan uplift can be subdivided into three groups, NE, NW and nearly EW in trending, and the boundary fault is a reverse fault nearly in EW direction. The deformation of marine structural layer is strong in the north and west and weak in the south and the east, strong in the upper and weak in the lower. The Laoshan fault-uplift area was formed by Indosinian-Early Yanshanian compressional thrust and late Yanshanian-Early Himalayan weak tension/tension torsion, and four structural styles of compressional, tensional, strike-slip and inversional are recognized. Through the analysis of their forming process, it is revealed that the Laoshan uplift is an old uplift formed in Caledonian period. It was a stable platform in Hercynian. In the Indosinian period, the northern foreland basin was probably a foreuplift flexural belt, formed on an anticline with increasing amplitude. The early Yanshanian fault anticline was a reformed fault anticline. The uplifting was basically stopped in middle Yanshanian stage. The uplifting and denudation happened in late Yanshanian-early Himalayan period, and local residual depressions developed. The overall subsidence began in late Himalayan. Combined with the analysis of oil and gas geological conditions, it is considered that the Gaoshi stable zone in the south of the Laoshan uplift is a favorable region for Marine oil and gas exploration, and the lower structural layer from Sinian to Silurian is weak in deformation and transformation. It should be also a favorable layer for oil and gas exploration.

     

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