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以高分辨率层序地层学和沉积学理论为指导,通过综合运用地震、测录井、岩芯等资料,对马海东构造带古近系下干柴沟组下段进行了高分辨率层序地层学研究。研究区共识别出不同规模的层序界面共6种类型,包括角度不整合、大规模冲刷面、中等规模冲刷面、小型河道下切面、地层样式转换面和沉积环境转换面。在层序界面识别的基础上,将目的层段划分为1个长期基准面旋回(LSC1)、3个中期基准面旋回(MSC1-MSC3)和12个短期基准面旋回(SSC1-SSC12),其中MSC2发育低可容纳空间向上“变深”非对称型(A1)旋回结构,MSC1、MSC3发育高可容纳空间向上“变深”非对称型(A2)旋回结构。建立了研究区层序地层等时对比格架,探讨了各中期层序沉积微相特征和砂体展布规律,结果表明,MSC2中期旋回内发育辫状河道心滩沉积微相,沉积物以砂砾岩、含砾粗砂岩、中细砂岩为主,砂体垂向厚层叠置,横向广泛连通,为研究区最为有利砂体发育层段。
Under the guidance of high-resolution sequence stratigraphy and sedimentology theory, the high resolution sequence stratigraphy of the lower Paleogene Lower Ganchaigou Formation in the Mahaidong tectonic belt was made by comprehensively using the data of earthquakes, logging wells and cores. Study. The study area identified a total of six types of sequence interfaces with different scales, including angle unconformity, large-scale erosion surface, medium-scale erosion surface, small river channel, strata-style conversion surface and sedimentary environment conversion surface. Based on the identification of sequence boundaries, the target intervals are divided into a long-term reference cycle (LSC1), three mid-term cycle (MSC1-MSC3) and 12 short-term reference cycle (SSC1-SSC12) MSC2 develops low accommodative space upwards to “deepen” asymmetric (A1) swirling structure, and MSC1, MSC3 develops highly accommodative space upward “deepened” asymmetric (A2) swirling structure. A series of isochronous frameworks of sequence stratigraphy in the study area were established. The characteristics of sedimentary microfacies and the distribution of sand body in each stage were discussed. The results show that the braided channel hearth sedimentary microfacies and sediment Sandy conglomerate, gravel coarse sandstone and medium-fine sandstone, and the sand bodies are vertically thickly stacked and horizontally widely connected, which is the most favorable sand body development section in the study area.