镇泾地区延安组底界侵蚀谷地震特征及其与煤层和砂体的关系

发布时间：2018-08-19 14:53

【摘要】：鄂尔多斯盆地延长组沉积后期的侵蚀谷发育十分广泛。在盆地西南缘镇泾地区三维地震所做的延10底等t0图上可以识别出沿NE、NW延伸的主谷和沿NW、NE次谷体系。地震剖面上主谷为宽缓的不对称"U"形,次谷则呈相对窄"U"形和"V"形两种形态。通过钻井延9、延10砂厚、砂地比、煤厚、煤地比的统计对比并结合井与侵蚀谷的位置关系发现侵蚀谷内煤层有加厚趋势,但砂厚无明显变化。该区延9及延10的煤厚与对应层位的强振幅呈正相关,但振幅平面形态与侵蚀谷无明显关系,反映延安组发育煤层的沼泽环境形态和范围并不完全限定在古河谷内。侵蚀谷砂厚与弱振幅关系不明显,以往解释的延10时期SW—NE古流向及砂体展布与此次解释的主谷方向基本一致。
[Abstract]:The erosion valley of Yanchang formation in Ordos Basin is widely developed in late sedimentary period. The main valley and the NE subvalley system extending along the NENW can be identified from the isotenth-t _ 0 diagram of the 10-base extension made by the 3-D earthquake in Zhenjing area, southwest margin of the basin. In the seismic profile, the main valley is a broad and slow asymmetric "U" shape, while the secondary valley is relatively narrow "U" shape and "V" shape. Through the statistical comparison of drilling extension 9, 10 sand thickness, sand to soil ratio, coal thickness and coal to ground ratio, and combining with the position relationship between well and erosion valley, it is found that the coal seam in the eroded valley has a tendency of thickening, but the sand thickness has no obvious change. The coal thickness of Yan 9 and Yan 10 is positively correlated with the strong amplitude of the corresponding horizon, but the amplitude plane form has no obvious relationship with the erosion valley, which indicates that the swamp environment and range of the coal seam developed in Yan'an formation are not completely limited to the Guhe Valley. The relationship between sand thickness and weak amplitude of erosion valley is not obvious, and the direction of SW-NE paleodirection and sand body distribution in the past 10 years is basically the same as that of the main valley in this interpretation.
【作者单位】：西北大学大陆动力学国家重点实验室/西北大学地质学系;中国石化华北分公司研究院;新疆地质矿产勘查开发局第九地质大队;
【基金】：国家自然科学基金项目(41390451)~~
【分类号】：P618.11

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